Peugeot 405 Haynes (petrol). Manual - part 12

XU series engines

15 Slacken and remove the retaining bolts,
and remove the oil seal carrier from the front
(timing belt) end of the cylinder block, along
with its gasket (where fitted) (see illustration).
16 Remove the oil pump drive chain, and
slide the drive sprocket and spacer (where
fitted) off the end of the crankshaft. Remove
the Woodruff key, and store it with the
sprocket for safe-keeping (see illustrations).
17 The main bearing caps should be
numbered 1 to 5, starting from the
transmission (flywheel/driveplate) end of the
engine (see illustration). If not, mark them
accordingly using a centre-punch. Also note
the correct fitted depth of the rear crankshaft
oil seal in the bearing cap.
18 On 1761 cc engines, undo the two bolts
(one at the front of the block, and one at the
rear) securing the centre main bearing cap to

the block. Remove the bolts, along with their
sealing washers.
19 On all engines, slacken and remove the
main bearing cap retaining bolts/nuts, and lift
off each bearing cap. Recover the lower
bearing shells, and tape them to their
respective caps for safe-keeping. Also
recover the lower thrustwasher halves from
the side of No 2 main bearing cap (see
illustration). Remove the rubber sealing strips
from the sides of No 1 main bearing cap, and
discard them.
20 Lift out the crankshaft, and discard the
rear oil seal (see illustration).
21 Recover the upper bearing shells from the
cylinder block, and tape them to their
respective caps for safe-keeping (see
illustration). Remove the upper thrustwasher
halves from the side of No 2 main bearing,
and store them with the lower halves.

Engine removal and overhaul  2C•11

11.16b  . . . then slide off the 

drive sprocket . . .

11.19  Removing No 2 main bearing cap.

Note the thrustwasher (arrowed)

11.17  Main bearing cap identification

markings (arrowed)

11.16c  . . . and remove the Woodruff key

from the crankshaft

11.16a  Remove the oil pump 

drive chain . . .

11.15  Removing the oil seal carrier from

the front of the cylinder block - XU engine

2C

11.20  Lifting out the crankshaft - 

XU series engine

11.21  Remove the upper main bearing

shells from the cylinder block/crankcase,

and store them with their lower shells

12.1  Cylinder block core plugs (arrowed)

12 Cylinder block/crankcase -

cleaning and inspection

2

Cleaning

1 Remove all external components and
electrical switches/sensors from the block.
For complete cleaning, the core plugs should
ideally be removed (see illustration). Drill a
small hole in the plugs, then insert a self-
tapping screw into the hole. Pull out the plugs
by pulling on the screw with a pair of grips, or
by using a slide hammer.
2 On aluminium block engines with wet liners,
remove the liners, referring to paragraph 18.
3 Where applicable, undo the retaining bolt
and remove the piston oil jet spray tube from
inside the cylinder block.
4 Scrape all traces of gasket from the cylinder
block/crankcase, and from the main bearing

ladder (where fitted), taking care not to
damage the gasket/sealing surfaces.
5 Remove all oil gallery plugs (where fitted).
The plugs are usually very tight - they may
have to be drilled out, and the holes re-
tapped. Use new plugs when the engine is
reassembled.
6 If any of the castings are extremely dirty, all
should be steam-cleaned.
7 After the castings are returned, clean all oil
holes and oil galleries one more time. Flush all
internal passages with warm water until the
water runs clear. Dry thoroughly, and apply a
light film of oil to all mating surfaces, to
prevent rusting. On cast-iron block engines,
also oil the cylinder bores. If you have access
to compressed air, use it to speed up the
drying process, and to blow out all the oil
holes and galleries. 

8 If the castings are not very dirty, you can do
an adequate cleaning job with hot (as hot as
you can stand!), soapy water and a stiff brush.
Take plenty of time, and do a thorough job.
Regardless of the cleaning method used, be
sure to clean all oil holes and galleries very
thoroughly, and to dry all components well.
On cast-iron block engines, protect the
cylinder bores as described above, to prevent
rusting.
9 All threaded holes must be clean, to ensure
accurate torque readings during reassembly.
To clean the threads, run the correct-size tap
into each of the holes to remove rust,
corrosion, thread sealant or sludge, and to
restore damaged threads (see illustration). If
possible, use compressed air to clear the
holes of debris produced by this operation.

10 Apply suitable sealant to the new oil
gallery plugs, and insert them into the holes in
the block. Tighten them securely.
11 Where applicable, clean the threads of the
piston oil jet retaining bolt, and apply a drop
of thread-locking compound to the bolt
threads. Refit the piston oil jet spray tube to
the cylinder block, and tighten its retaining
bolt to the specified torque setting.
12 If the engine is not going to be
reassembled right away, cover it with a large
plastic bag to keep it clean; protect all mating
surfaces and the cylinder bores as described
above, to prevent rusting.

Inspection

Cast-iron cylinder block

13 Visually check the castings for cracks and
corrosion. Look for stripped threads in the
threaded holes. If there has been any history
of internal water leakage, it may be worthwhile
having an engine overhaul specialist check
the cylinder block/crankcase with special
equipment. If defects are found, have them
repaired if possible, or renew the assembly.
14 Check each cylinder bore for scuffing and
scoring. Check for a wear ridge at the top of the
cylinder, indicating that the bore is badly worn.
15 If the necessary measuring equipment is
available, measure the bore diameter of each
cylinder liner at the top (just under the wear
ridge), centre, and bottom of the cylinder
bore, parallel to the crankshaft axis.
16 Next, measure the bore diameter at the
same three locations, at right-angles to the
crankshaft axis. Compare the results with the
figures given in the Specifications. Where no
figures are stated by Peugeot, if there is any
doubt about the condition of the cylinder
bores seek the advice of a Peugeot dealer or
suitable engine reconditioning specialist.
17 At the time of writing, it was not clear
whether oversize pistons were available for all
models. Consult your Peugeot dealer for the
latest information on piston availability. If
oversize pistons are available then it may be
possible to have the cylinder bores rebored
and fit the oversize pistons. If it proves
oversize pistons are not available, and the
bores are worn, renewal of the block seems to
be the only option.

Aluminium cylinder block 
with wet liners

18 Remove the liner clamps (where used),
then use a hard wood drift to tap out each
liner from the inside of the cylinder block.
When all the liners are released, tip the
cylinder block/crankcase on its side and
remove each liner from the top of the block.
As each liner is removed, stick masking tape
on its left-hand (transmission side) face, and
write the cylinder number on the tape. No 1
cylinder is at the transmission (flywheel/
driveplate) end of the engine. Remove the O-
ring from the base of each liner, and discard
(see illustrations).
19 Check each cylinder liner for scuffing and
scoring. Check for signs of a wear ridge at the
top of the liner, indicating that the bore is
excessively worn.
20 If the necessary measuring equipment is
available, measure the bore diameter of each
cylinder liner at the top (just under the wear
ridge), centre, and bottom of the cylinder
bore, parallel to the crankshaft axis.
21 Next, measure the bore diameter at the
same three locations, at right-angles to the
crankshaft axis. Compare the results with the
figures given in the Specifications.
22 Repeat the procedure for the remaining
cylinder liners.
23 If the liner wear exceeds the permitted
tolerances at any point, or if the cylinder liner
walls are badly scored or scuffed, then
renewal of the relevant liner assembly will be
necessary. If there is any doubt about the
condition of the cylinder bores, seek the
advice of a Peugeot dealer or engine recondi-
tioning specialist.
24 If renewal is necessary, new liners,
complete with pistons and piston rings, can
be purchased from a Peugeot dealer. Note
that it is not possible to buy liners individually
- they are supplied only as a matched
assembly complete with piston and rings.
25 To allow for manufacturing tolerances,
pistons and liners are separated into three
size groups. The size group of each piston is
indicated by a letter (A, B or C) stamped onto
its crown, and the size group of each liner is
indicated by a series of 1 to 3 notches on the
upper lip of the liner; a single notch for 
group A, two notches for group B, and three

2C•12 Engine removal and overhaul

12.9  Cleaning a cylinder block threaded

hole using a suitable tap

12.18b  . . . and recover the bottom 

O-ring seal (arrowed)

12.18a  On aluminium block engines,

remove each liner . . .

Warning: Wear eye protection
when using compressed air!

Warning: Wear eye protection
when cleaning out these holes
in this way!

A good alternative is to
inject aerosol-applied water-
dispersant lubricant into
each hole, using the long

spout usually supplied.

notches for group C. Ensure that each piston
and its respective liner are both of the same
size group. It is permissible to have different
size group piston and liner assemblies fitted
to the same engine, but never fit a piston of
one size group to a liner in a different group.
26 Prior to installing the liners, thoroughly
clean the liner mating surfaces in the cylinder
block, and use fine abrasive paper to polish
away any burrs or sharp edges which might
damage the liner O-rings. Clean the liners and
wipe dry, then fit a new O-ring to the base of
each liner. To aid installation, apply a smear of
oil to each O-ring and to the base of the liner.
27 If the original liners are being refitted, use
the marks made on removal to ensure that
each is refitted the correct way round, and is
inserted into its original position. Insert each
liner into the cylinder block, taking care not to
damage the O-ring, and press it home as far
as possible by hand. Using a hammer and a
block of wood, tap each liner lightly but fully
onto its locating shoulder. Wipe clean, then
lightly oil, all exposed liner surfaces, to
prevent rusting.
28 With all four liners correctly installed, use
a dial gauge (or a straight-edge and feeler
blade) to check that the protrusion of each
liner above the upper surface of the cylinder
block is within the limits given in the Specifi-
cations. The maximum difference between
any two liners must not be exceeded.
29 If new liners are being fitted, it is
permissible to interchange them to bring the
difference in protrusion within limits. Keep
each piston with its respective liner.
30 If liner protrusion cannot be brought
within limits, seek the advice of a Peugeot
dealer or engine reconditioning specialist
before proceeding with the engine rebuild.

13 Piston/connecting rod

assembly - inspection

3

1 Before the inspection process can begin,
the piston/connecting rod assemblies must
be cleaned, and the original piston rings
removed from the pistons.
2 Carefully expand the old rings over the top
of the pistons. The use of two or three old
feeler blades will be helpful in preventing the
rings dropping into empty grooves (see
illustration). Be careful not to scratch the
piston with the ends of the ring. The rings are
brittle, and will snap if they are spread too far.
They’re also very sharp - protect your hands
and fingers. Note that the third ring
incorporates an expander. Always remove the
rings from the top of the piston. Keep each set
of rings with its piston if the old rings are to be
re-used.
3 Scrape away all traces of carbon from the
top of the piston. A hand-held wire brush (or a
piece of fine emery cloth) can be used, once
the majority of the deposits have been
scraped away.

4 Remove the carbon from the ring grooves
in the piston, using an old ring. Break the ring
in half to do this (be careful not to cut your
fingers - piston rings are sharp). Be careful to
remove only the carbon deposits - do not
remove any metal, and do not nick or scratch
the sides of the ring grooves.
5 Once the deposits have been removed,
clean the piston/connecting rod assembly
with paraffin or a suitable solvent, and dry
thoroughly. Make sure that the oil return holes
in the ring grooves are clear.
6 If the pistons and cylinder bores are not
damaged or worn excessively, and if the
cylinder block does not need to be rebored,
the original pistons can be refitted. Normal
piston wear shows up as even vertical wear
on the piston thrust surfaces, and slight
looseness of the top ring in its groove. New
piston rings should always be used when the
engine is reassembled.
7 Carefully inspect each piston for cracks
around the skirt, around the gudgeon pin
holes, and at the piston ring “lands” (between
the ring grooves).
8 Look for scoring and scuffing on the piston
skirt, holes in the piston crown, and burned
areas at the edge of the crown. If the skirt is
scored or scuffed, the engine may have been
suffering from overheating, and/or abnormal
combustion which caused excessively high
operating temperatures. The cooling and
lubrication systems should be checked
thoroughly. Scorch marks on the sides of the
pistons show that blow-by has occurred. A
hole in the piston crown, or burned areas at
the edge of the piston crown, indicates that
abnormal combustion (pre-ignition, knocking,
or detonation) has been occurring. If any of
the above problems exist, the causes must be
investigated and corrected, or the damage will
occur again. The causes may include
incorrect ignition/injection pump timing, or a
faulty injector (as applicable).
9 Corrosion of the piston, in the form of
pitting, indicates that coolant has been
leaking into the combustion chamber and/or
the crankcase. Again, the cause must be
corrected, or the problem may persist in the
rebuilt engine.
10 On aluminium-block engines with wet
liners, it is not possible to renew the pistons
separately; pistons are only supplied with

piston rings and a liner, as a part of a matched
assembly (see Section 12). On iron-block
engines, pistons can be purchased from a
Peugeot dealer.
11 Examine each connecting rod carefully for
signs of damage, such as cracks around the
big-end and small-end bearings. Check that
the rod is not bent or distorted. Damage is
highly unlikely, unless the engine has been
seized or badly overheated. Detailed checking
of the connecting rod assembly can only be
carried out by a Peugeot dealer or engine
repair specialist with the necessary
equipment.
12 On XU series engines, due to the
tightening procedure for the connecting rod
big-end cap retaining nuts, it is highly
recommended that the big-end cap nuts and
bolts are renewed as a complete set prior to
refitting.
13 On all 8-valve engines the gudgeon pins
are an interference fit in the connecting rod
small-end bearing. Therefore, piston and/or
connecting rod renewal should be entrusted
to a Peugeot dealer or engine repair
specialist, who will have the necessary tooling
to remove and install the gudgeon pins.
14 On 16-valve engines, the gudgeon pins
are of the floating type, secured in position by
two circlips. On these engines, the pistons
and connecting rods can be separated as
follows.
15 Using a small flat-bladed screwdriver,
prise out the circlips, and push out the
gudgeon pin (see illustrations). Hand
pressure should be sufficient to remove the
pin. Identify the piston and rod to ensure

Engine removal and overhaul  2C•13

13.2  Removing a piston ring with the 

aid of a feeler gauge

2C

13.15a  On 16-valve engines, 

prise out the circlip . . .

13.15b  . . . and withdraw the gudgeon pin

correct reassembly. Discard the circlips - new
ones must be used on refitting.
16 Examine the gudgeon pin and connecting
rod small-end bearing for signs of wear or
damage. Wear can be cured by renewing both
the pin and bush. Bush renewal, however, is a
specialist job - press facilities are required,
and the new bush must be reamed accurately.
17 The connecting rods themselves should
not be in need of renewal, unless seizure or
some other major mechanical failure has
occurred. Check the alignment of the
connecting rods visually, and if the rods are
not straight, take them to an engine overhaul
specialist for a more detailed check.
18 Examine all components, and obtain any
new parts from your Peugeot dealer. If new
pistons are purchased, they will be supplied
complete with gudgeon pins and circlips.
Circlips can also be purchased individually.
19 Position the piston so that the arrow on
the piston crown is positioned as shown in
relation to the connecting rod big-end bearing
shell cutouts (see illustration). Apply a smear
of clean engine oil to the gudgeon pin. Slide it
into the piston and through the connecting
rod small-end. Check that the piston pivots
freely on the rod, then secure the gudgeon pin
in position with two new circlips. Ensure that
each circlip is correctly located in its groove in
the piston.

14 Crankshaft - inspection

2

Checking crankshaft endfloat

1 If the crankshaft endfloat is to be checked,
this must be done when the crankshaft is still
installed in the cylinder block/crankcase, but
is free to move (see Section 11).
2 Check the endfloat using a dial gauge in
contact with the end of the crankshaft. Push
the crankshaft fully one way, and then zero
the gauge. Push the crankshaft fully the other
way, and check the endfloat. The result can
be compared with the specified amount, and
will give an indication as to whether new
thrustwashers are required (see illustration).
3 If a dial gauge is not available, feeler blades
can be used. First push the crankshaft fully
towards the flywheel/driveplate end of the
engine, then use feeler blades to measure the
gap between the web of No 2 crankpin and
the thrustwasher (see illustration).

Inspection

4 Clean the crankshaft using paraffin or a
suitable solvent, and dry it, preferably with
compressed air if available. Be sure to clean
the oil holes with a pipe cleaner or similar
probe, to ensure that they are not obstructed.

5 Check the main and big-end bearing
journals for uneven wear, scoring, pitting and
cracking.
6 Big-end bearing wear is accompanied by
distinct metallic knocking when the engine is
running (particularly noticeable when the
engine is pulling from low speed) and some
loss of oil pressure.
7 Main bearing wear is accompanied by
severe engine vibration and rumble - getting
progressively worse as engine speed
increases - and again by loss of oil pressure.
8 Check the bearing journal for roughness by
running a finger lightly over the bearing
surface. Any roughness (which will be
accompanied by obvious bearing wear)
indicates that the crankshaft requires
regrinding (where possible) or renewal.
9 If the crankshaft has been reground, check
for burrs around the crankshaft oil holes (the
holes are usually chamfered, so burrs should
not be a problem unless regrinding has been
carried out carelessly). Remove any burrs with
a fine file or scraper, and thoroughly clean the
oil holes as described previously.
10 Using a micrometer, measure the
diameter of the main and big-end bearing
journals, and compare the results with the
Specifications 

(see illustration). By

measuring the diameter at a number of points
around each journal’s circumference, you will
be able to determine whether or not the
journal is out-of-round. Take the
measurement at each end of the journal, near
the webs, to determine if the journal is
tapered. Compare the results obtained with
those given in the Specifications. Where no
specified journal diameters are quoted, seek
the advice of a Peugeot dealer.
11 Check the oil seal contact surfaces at
each end of the crankshaft for wear and
damage. If the seal has worn a deep groove in
the surface of the crankshaft, consult an
engine overhaul specialist; repair may be
possible, but otherwise a new crankshaft will
be required.
12 At the time of writing, it was not clear
whether Peugeot produce oversize bearing
shells for all of these engines. On some
engines, if the crankshaft journals have not
already been reground, it may be possible to
have the crankshaft reconditioned, and to fit

14.10  Measuring a crankshaft big-end

journal diameter

2C•14 Engine removal and overhaul

13.15c  Piston and connecting rod

components

14.3  Checking crankshaft endfloat 

using feeler gauges

14.2  Checking crankshaft endfloat 

using a dial gauge

13.19  On 16-valve engines, on refitting

ensure that the piston arrow is positioned

as shown, in relation to the connecting rod

bearing shell cutout (a)

Warning: Wear eye protection
when using compressed air!

undersize shells (see Section 18). If no
undersize shells are available and the
crankshaft has worn beyond the specified
limits, it will have to be renewed. Consult your
Peugeot dealer or engine specialist for further
information on parts availability.

15 Main and big-end bearings -

inspection

2

1 Even though the main and big-end bearings
should be renewed during the engine
overhaul, the old bearings should be retained
for close examination, as they may reveal
valuable information about the condition of
the engine. The bearing shells are graded by
thickness, the grade of each shell being
indicated by the colour code marked on it.
2 Bearing failure can occur due to lack of
lubrication, the presence of dirt or other
foreign particles, overloading the engine, or
corrosion (see illustration). Regardless of the
cause of bearing failure, the cause must be
corrected (where applicable) before the
engine is reassembled, to prevent it from
happening again.
3 When examining the bearing shells, remove
them from the cylinder block/crankcase, the
main bearing ladder/caps (as appropriate), the
connecting rods and the connecting rod big-
end bearing caps. Lay them out on a clean
surface in the same general position as their
location in the engine. This will enable you to
match any bearing problems with the
corresponding crankshaft journal. Do not
touch any shell’s bearing surface with your
fingers while checking it, or the delicate
surface may be scratched.
4 Dirt and other foreign matter gets into the
engine in a variety of ways. It may be left in
the engine during assembly, or it may pass
through filters or the crankcase ventilation
system. It may get into the oil, and from there
into the bearings. Metal chips from machining
operations and normal engine wear are often
present. Abrasives are sometimes left in
engine components after reconditioning,
especially when parts are not thoroughly
cleaned using the proper cleaning methods.
Whatever the source, these foreign objects
often end up embedded in the soft bearing
material, and are easily recognised. Large
particles will not embed in the bearing, and
will score or gouge the bearing and journal.
The best prevention for this cause of bearing
failure is to clean all parts thoroughly, and
keep everything spotlessly-clean during
engine assembly. Frequent and regular engine
oil and filter changes are also recommended.
5 Lack of lubrication (or lubrication
breakdown) has a number of interrelated
causes. Excessive heat (which thins the oil),
overloading (which squeezes the oil from the
bearing face) and oil leakage (from excessive
bearing clearances, worn oil pump or high
engine speeds) all contribute to lubrication

breakdown. Blocked oil passages, which
usually are the result of misaligned oil holes in
a bearing shell, will also oil-starve a bearing,
and destroy it. When lack of lubrication is the
cause of bearing failure, the bearing material
is wiped or extruded from the steel backing of
the bearing. Temperatures may increase to
the point where the steel backing turns blue
from overheating.
6 Driving habits can have a definite effect on
bearing life. Full-throttle, low-speed operation
(labouring the engine) puts very high loads on
bearings, tending to squeeze out the oil film.
These loads cause the bearings to flex, which
produces fine cracks in the bearing face
(fatigue failure). Eventually, the bearing
material will loosen in pieces, and tear away
from the steel backing.
7 Short-distance driving leads to corrosion of
bearings, because insufficient engine heat is
produced to drive off the condensed water
and corrosive gases. These products collect
in the engine oil, forming acid and sludge. As
the oil is carried to the engine bearings, the
acid attacks and corrodes the bearing
material.
8 Incorrect bearing installation during engine
assembly will lead to bearing failure as well.
Tight-fitting bearings leave insufficient bearing
running clearance, and will result in oil
starvation. Dirt or foreign particles trapped
behind a bearing shell result in high spots on
the bearing, which lead to failure.
9 Do not touch any shell’s bearing surface
with your fingers during reassembly; there is a
risk of scratching the delicate surface, or of
depositing particles of dirt on it.
10 As mentioned at the beginning of this
Section, the bearing shells should be renewed
as a matter of course during engine overhaul;
to do otherwise is false economy. Refer to
Section 18 for details of bearing shell
selection.

16 Engine overhaul - reassembly

sequence

1 Before reassembly begins, ensure that all
new parts have been obtained, and that all
necessary tools are available. Read through
the entire procedure carefully to familiarise
yourself with the work involved, and to ensure
that all items necessary for reassembly of the
engine are at hand. In addition to all normal
tools and materials, thread-locking compound
will be needed. A suitable tube of liquid
sealant will also be required for the joint faces
that are fitted without gaskets. It is
recommended that Peugeot’s own product(s)
are used, which are specially formulated for
this purpose.
2 In order to save time and avoid problems,
engine reassembly can be carried out in the
following order:

a) Crankshaft (Section 18).
b) Piston/connecting rod assemblies

(Section 19).

c) Oil pump .
d) Sump (See Part A or B - as applicable).
e) Flywheel (See Part A or B - as applicable).
f) Cylinder head (See Part A or B - as

applicable).

g) Timing belt tensioner and sprockets, and

timing belt (See Part A or B - as
applicable).

h) Engine external components.

3 At this stage, all engine components should
be absolutely clean and dry, with all faults
repaired. The components should be laid out
(or in individual containers) on a completely
clean work surface.

17 Piston rings - refitting

3

1 Before fitting new piston rings, the ring end
gaps must be checked as follows.
2 Lay out the piston/connecting rod
assemblies and the new piston ring sets, so
that the ring sets will be matched with the
same piston and cylinder during the end gap
measurement and subsequent engine
reassembly.
3 Insert the top ring into the first cylinder, and
push it down the bore using the top of the
piston. This will ensure that the ring remains
square with the cylinder walls. Position the
ring near the bottom of the cylinder bore, at
the lower limit of ring travel. Note that the top
and second compression rings are different.
The second ring is easily identified by the step
on its lower surface, and by the fact that its
outer face is tapered.
4 Measure the end gap using feeler blades.
5 Repeat the procedure with the ring at the
top of the cylinder bore, at the upper limit of
its travel, and compare the measurements

Engine removal and overhaul  2C•15

15.2  Typical bearing failures

2C

with the figures given in the Specifications
(see illustration). Where no figures are given,
seek the advice of a Peugeot dealer or engine
reconditioning specialist.
6 If the gap is too small (unlikely if genuine
Peugeot parts are used), it must be enlarged,
or the ring ends may contact each other
during engine operation, causing serious
damage. Ideally, new piston rings providing
the correct end gap should be fitted. As a last
resort, the end gap can be increased by filing
the ring ends very carefully with a fine file.
Mount the file in a vice equipped with soft
jaws, slip the ring over the file with the ends
contacting the file face, and slowly move the
ring to remove material from the ends. Take
care, as piston rings are sharp, and are easily
broken.
7 With new piston rings, it is unlikely that the
end gap will be too large. If the gaps are too
large, check that you have the correct rings
for your engine and for the particular cylinder
bore size.
8 Repeat the checking procedure for each
ring in the first cylinder, and then for the rings
in the remaining cylinders. Remember to keep
rings, pistons and cylinders matched up.
9 Once the ring end gaps have been checked
and if necessary corrected, the rings can be
fitted to the pistons.
10 Fit the piston rings using the same
technique as for removal. Fit the bottom (oil
control) ring first, and work up. When fitting
the oil control ring, first insert the expander
(where fitted), then fit the ring with its gap
positioned 180° from the expander gap.
Ensure that the second compression ring is
fitted the correct way up, with its identification
mark (either a dot of paint or the word “TOP”
stamped on the ring surface) at the top, and
the stepped surface at the bottom (see
illustration). Arrange the gaps of the top and
second compression rings 120° either side of
the oil control ring gap. Note: Always follow
any instructions supplied with the new piston
ring sets - different manufacturers may specify
different procedures. Do not mix up the top
and second compression rings, as they have
different cross-sections.

18 Crankshaft - refitting and

main bearing running
clearance check

4

Selection of new bearing shells

TU series engine

1 On early engines, both upper and lower
main bearing shells were of the same
thickness, with only two sizes of bearing
shells being available: a standard size for use
with the standard crankshaft, and a set of
oversize bearing shells for use once the
crankshaft bearing journals have been
reground.
2 However, since February 1992, the
specified main bearing running clearance has
been significantly reduced. This has been
achieved by the introduction of three different
grades of bearing shell, in both standard sizes
and oversizes. The grades are indicated by a
colour-coding marked on the edge of each
shell, which denotes the shell’s thickness, as
listed in the following table. The upper shell on
all bearings is of the same size (class B,
colour code black), and the running clearance
is controlled by fitting a lower bearing shell of

the required thickness. This arrangement has
been fitted to all engines produced since
February 1992 and, if possible, should also be
fitted to earlier engines during overhaul. Seek
the advice of your Peugeot dealer on parts
availability and the best course of action when
ordering new bearing shells.

Aluminium block engine

Bearing Thickness 

(mm)

colour code

Standard

Undersize

Blue (class A)

1.823

1.973

Black (class B)

1.835

1.985

Green (class C)

1.848

1.998

Cast-iron block engine 

Bearing Thickness 

(mm)

colour code

Standard

Undersize

Blue (class A)

1.844

1.994

Black (class B)

1.858

2.008

Green (class C)

1.869

2.019

3 On early engines, the correct size of bearing
shell must be selected by measuring the
running clearance as described under the
sub-heading below.
4 On engines produced since February 1992,
when the new bearing shell sizes were
introduced, the crankshaft and cylinder
block/crankcase have reference marks on
them, to identify the size of the journals and
bearing bores.
5 The cylinder block reference marks are on
the right-hand (timing belt) end of the block,
and the crankshaft reference marks are on the
right-hand (timing belt) end of the crankshaft,
on the right-hand web of No 4 crankpin (see
illustration). These marks can be used to
select bearing shells of the required thickness
as follows.
6 On both the crankshaft and block there are
two lines of identification: a bar code, which is
used by Peugeot during production, and a
row of five letters. The first letter in the
sequence refers to the size of No 1 bearing (at
the flywheel/driveplate end). The last letter in
the sequence (which is followed by an arrow)
refers to the size of No 5 main bearing. These
marks can be used to select the required
bearing shell grade as follows.
7 Obtain the identification letter of both the
relevant crankshaft journal and the cylinder
block bearing bore. Noting that the cylinder

2C•16 Engine removal and overhaul

17.5  Measuring a piston ring end gap

1  Oil control ring
2  Second compression ring
3  Top compression ring

17.10  Piston ring fitting diagram (typical)

18.5  Cylinder block and crankshaft main

bearing  reference marking locations - 

TU series engines

block letters are listed across the top of the
chart, and the crankshaft letters down the
side, trace a vertical line down from the
relevant cylinder block letter, and a horizontal
line across from the relevant crankshaft letter,
and find the point at which both lines cross.
This crossover point will indicate the grade of
lower bearing shell required to give the
correct main bearing running clearance. For
example, the illustration shows cylinder block
reference G, and crankshaft reference T,
crossing at a point within the area of Class A,
indicating that a blue-coded (Class A) lower
bearing shell is required to give the correct
main bearing running clearance (see
illustration).
8 Repeat this procedure so that the required
bearing shell grade is obtained for each of the
five main bearing journals.

XU series engine

9 On some early engines, both the upper and
lower bearing shells were of the same
thickness.
10 However, on later engines the main
bearing running clearance was significantly
reduced. To enable this to be done, four
different grades of bearing shell were
introduced. The grades are indicated by a
colour-coding marked on the edge of each
shell, which denotes the shell’s thickness, as
listed in the following table. The upper shell on
all bearings is of the same size, and the
running clearance is controlled by fitting a
lower bearing shell of the required thickness.
Note: On all XU series engines, upper shells
are easily distinguished from lower shells, by
their grooved bearing surface; the lower shells
have a plain surface. It was not clear at 
the time of writing whether undersize bearing
shells are available for 1998 cc engine. Refer
to your Peugeot dealer for the latest
information.

1580 cc, 1761 cc and 1905 cc engines

Bearing colour

Thickness (mm)

code

Standard

Undersize

Upper bearing:

Yellow

1.856

2.006

Lower bearing:

Blue (Class A)

1.836

1.986

Black (Class B)

1.848

1.998

Green (Class C)

1.859

2.009

Red (Class D)

1.870

2.020

1998 cc engines

Bearing colour

Thickness (mm)

code

Standard

Undersize

Upper bearing:

Black

1.847

N/A

Lower bearing:

Blue (Class A)

1.844

N/A

Black (Class B)

1.857

N/A

Green (Class C)

1.866

N/A

Red (Class D)

1.877

N/A

11 On most later engines, new bearing shells
can be selected using the reference marks on
the cylinder block/crankcase. The cylinder
block marks identify the diameter of the
bearing bores, and the crankshaft marks the
diameter of the crankshaft journals. Where no
marks are present, the bearing shells can only
be selected by checking the running
clearance (see below).
12 The cylinder block reference marks are on
the left-hand (flywheel/driveplate) end of the
block, and the crankshaft reference marks are
on the end web of the crankshaft (see
illustration). These marks can be used to
select bearing shells of the required thickness
as follows.
13 On both the crankshaft and block there
are two lines of identification: a bar code,
which is used by Peugeot during production,
and a row of five letters. The first letter in the
sequence refers to the size of No 1 bearing (at

the flywheel/driveplate end). The last letter in
the sequence (which is followed by an arrow)
refers to the size of No 5 main bearing. These
marks can be used to select the required
bearing shell grade as follows.
14 Obtain the identification number/letter of
both the relevant crankshaft journal and the
cylinder block bearing bore. Noting that the
crankshaft references are listed across the
top of the chart, and the cylinder block
references down the side, trace a vertical line
down from the relevant crankshaft reference,
and a horizontal line across from the relevant
cylinder block reference, and find the point at
which both lines cross. This crossover point
will indicate the grade of lower bearing shell
required to give the correct main bearing
running clearance. For example, the
illustration shows crankshaft reference 6, and
cylinder block reference H, crossing at a point
within the RED area, indicating that a Red-
coded (Class D) lower bearing shell is required
to give the correct main bearing running
clearance (see illustration).
15 Repeat this procedure so that the
required bearing shell grade is obtained for
each of the five main bearing journals.
16 Seek the advice of your Peugeot dealer
on parts availability, and on the best course of
action when ordering new bearing shells.
Note: On early models, at overhaul it is
recommended that the later bearing shell
arrangement is fitted. This, however, should
only be done if the lubrication system
components are upgraded (necessitating
replacement of the oil pump relief valve piston
and spring as well as the pump sprocket and

Engine removal and overhaul  2C•17

A  Bar Code (for production use only)
B  Reference marks

18.12  Cylinder block and crankshaft main

bearing reference marking locations - 

XU series engines

18.7  Main bearing shell selection chart, for use with TU series engines - 

see text for further information

2C

drive chain) at the same time. If the new
bearing arrangement is to be used without
uprating the lubrication system, Peugeot state
that  Blue (Class A) lower bearing shells should
be fitted. Refer to your Peugeot dealer for
further information.
17 Since there are no bearing identification
marks, the relevant main bearing shell grade
must be selected by measuring the main
bearing running clearance.

Main bearing 
running clearance check

TU series engine

18 On early engines, if the modified bearing
shells are to be fitted, obtain a set of new
black (Class B) upper bearing shells and new
blue (Class A) lower bearing shells. On later
(February 1992-on) engines where the
modified bearing shells are already fitted, the
running clearance check can be carried out
using the original bearing shells. However, it is
preferable to use a new set, since the results
obtained will be more conclusive.
19 Clean the backs of the bearing shells, and
the bearing locations in both the cylinder
block/crankcase and the main bearing ladder.
20 Press the bearing shells into their
locations, ensuring that the tab on each shell
engages in the notch in the cylinder

block/crankcase or main bearing ladder
location. Take care not to touch any shell’s
bearing surface with your fingers. Note that
the grooved bearing shells, both upper and
lower, are fitted to Nos 2 and 4 main bearings
(see illustration). If the original bearing shells
are being used for the check, ensure that they
are refitted in their original locations. The
clearance can be checked in either of two
ways.
21 One method (which will be difficult to
achieve without a range of internal
micrometers or internal/external expanding
calipers) is to refit the main bearing ladder
casting to the cylinder block/crankcase, with
the bearing shells in place. With the casting
retaining bolts correctly tightened, measure
the internal diameter of each assembled pair
of bearing shells. If the diameter of each
corresponding crankshaft journal is measured
and then subtracted from the bearing internal
diameter, the result will be the main bearing
running clearance.
22 The second (and more accurate) method
is to use a product known as “Plastigauge”.
This consists of a fine thread of perfectly-
round plastic, which is compressed between
the bearing shell and the journal. When the
shell is removed, the plastic is deformed, and
can be measured with a special card gauge

supplied with the kit. The running clearance is
determined from this gauge. Plastigauge
should be available from your Peugeot dealer,
otherwise enquiries at one of the larger
specialist motor factors should produce the
name of a stockist in your area. The
procedure for using Plastigauge is as follows.
23 With the main bearing upper shells in
place, carefully lay the crankshaft in position.
Do not use any lubricant; the crankshaft
journals and bearing shells must be perfectly
clean and dry.
24 Cut several lengths of the appropriate-
size Plastigauge (they should be slightly
shorter than the width of the main bearings),
and place one length on each crankshaft
journal axis (see illustration).
25 With the main bearing lower shells in
position, refit the main bearing ladder casting,
tightening its retaining bolts as described in
paragraph 45. Take care not to disturb the
Plastigauge, and do not rotate the crankshaft
at any time during this operation.
26 Remove the main bearing ladder casting,
again taking great care not to disturb the
Plastigauge or rotate the crankshaft.
27 Compare the width of the crushed
Plastigauge on each journal to the scale
printed on the Plastigauge envelope, to obtain
the main bearing running clearance (see
illustration). Compare the clearance
measured with that given in the Specifications
at the start of this Chapter.
28 If the clearance is significantly different
from that expected, the bearing shells may be
the wrong size (or excessively worn, if the
original shells are being re-used). Before
deciding that different-size shells are required,
make sure that no dirt or oil was trapped
between the bearing shells and the caps or
block when the clearance was measured. If
the Plastigauge was wider at one end than at
the other, the crankshaft journal may be
tapered.
29 If the clearance is not as specified, use
the reading obtained, along with the shell
thicknesses quoted above, to calculate the
necessary grade of bearing shells required.
When calculating the bearing clearance
required, bear in mind that it is always better
to have the running clearance towards the

2C•18 Engine removal and overhaul

18.14  Main bearing shell selection chart, for use with XU series engines - 

see text for further information

18.20  On TU series engines, note that the

grooved bearing shells are fitted to 

Nos 2 and 4 main bearing journals

18.27  Measuring the width of the

deformed Plastigauge using the scale on

the card provided

18.24  Plastigauge in place on a crankshaft

main bearing journal