Lotus Elise / Lotus Exige. Manual - part 65

                

  

Lotus Service Notes                                 Section KH

Page 5

To refill the system:

1

Refit the hoses to the feed and return pipes and close the cylinder block drain tap.

2.

Remove the right hand front wheelarch liner and open the air bleed plug on the radiator outlet hose.  From
within the engine bay, open the air bleed plug in the heater return hose at the left hand rear of the engine
bay.

3.

Fill with the recommended coolant mix via the header tank and close the bleed plugs when a steady
stream of coolant is expelled.

4.

Start the engine and allow to idle, and periodically open the bleed plugs to allow any trapped air to be
expunged.  Top up the header tank when necessary, and fit the pressure cap when required to prevent
overflow.  When the cooling fans have cut in and then out, stop the engine and allow to cool.  Recheck
coolant level when fully cold.

KH.4 - RADIATOR & COOLING FAN

The aluminium cored radiator is positioned horizontally on top of the composite 'crash structure' in the

front services compartment.  A composite moulding is used to mount the radiator, and also, via extensions at
each side, to provide a mounting point for the inside front of the clamshell wheelarch.  The radiator must be
removed for access to the cooling fans.

To Remove Radiator
1.

Remove the front clamshell (see section BR).

2.

Drain the coolant and disconnect the feed and return hoses from the radiator.

3.

If the car is equipped with air conditioning, de-pressurise the system and recover the refrigerant via the
service ports near the evaporator.

4.

Remove the two radiator outlet air deflector panels, release all tie wraps and fixings securing wiring
hanesses and pipes to the radiator mounting panel, and disconnect the radiator fan harness plugs.

5.

If the car is fitted with front mounted oil coolers, disconnect the feed and return hoses from both coolers
and plug all ports to limit oil spillage.  Remove the mounting brackets from the coolers and crash struc-
ture.

6.

Release the single fixing at the bottom of each side extension securing the mounting panel to the bottom
flange of the crash structure.

7.

Release the three fixings securing the back edge of the mounting panel to the vertical flange on the crash
structure, and the three fixings along the front edge of the panel.

8.

Withdraw the radiator mounting panel with radiator/(condenser)/cooling fans assembly.

9.

Each cooling fan is secured two studs and nuts to either the radiator flange bracket, or, on a.c. cars to the
condenser.  The condenser is secured to the radiator lower flange by two studs at the front edge, and by
two pairs of screws at the rear edge.  The radiator is fixed to the mounting panel by brackets at the front
and rear.  Note the foam packing used between the radiator and mountign panel to ensure that all ducted
air flows through the radiator matrix.

10. Refit the radiator in reverse order to removal, ensuring that the foam packing is re-installed.  Refill with

coolant and bleed as detailed in sub-section KH.3.  Re-charge refrigerant system.

                

  

 Lotus Service Notes                                 Section KH

Page 6

Radiator Mounting

Rear mounting

Front mounting

spreader plate

spreader plate

Radiator
mounting
panel

Front
mounting
bracket

Rear
mounting
bracket

Engine
cooling
radiator

Air conditioning
condenser

Fan fixing

(if fitted)

Cooling fan

        p105

                

  

Lotus Service Notes                                 Section KH

Page 7

KH.5 - RADIATOR FAN & RE-CIRC. PUMP CONTROL

The two cooling fans are fitted beneath the radiator or (with a.c.) condenser/radiator package, and the

coolant re-circulation pump is mounted below the header tank.  Both the fans and pump are controlled by the
engine management ECU using data provided by the engine coolant temperature sensor mounted in the back
of the cylinder head.

The cooling fans are switched as a pair, and will operate at half speed (connected in series) when coolant

temperature reaches 98°C on rise, and switch off at 94°C on fall.  The fans will also operate at half speed
irrespective of coolant temperature if the a.c. is switched on and the compressor is running.  If coolant tem-
perature rises to 103°C, the fans will switch to full speed (connected in parallel), reverting to half speed at 98°C.

The fans will also run at half speed, unless high coolant temperature dictates otherwise, when the a.c. is

switched on and the compressor is running, or if the engine management system detects a fault with the inlet
air temperature or coolant temperature circuits.

At road speeds in excess of 85 mph (135 km/h), equating to the fan stall speed, all fan functions are

switched off.

Heat Soak

In order to help control engine temperature after switching off an engine whose temperature is over 88°C,

the ECU will remain powered for a period of 20 minutes to allow heat soak management.

A coolant re-circulation electric pump is mounted below the coolant header tank and is plumbed into the

heater supply line.  When energised, the pump circulates coolant through the engine and heater system,
drawing coolant from the back of the cylinder head, and pumping it through the heater matrix to the heater
return pipe and back into the thermostat housing.  The pump functions only with ignition off in conditions where
the ECU remains live.  The pump is then activated at coolant temperatures over 110°C, switching off at 100°C
on fall.  If temperature should rise to 115°C, the pump will be supplemented by the two cooling fans running at
half speed, switching off at 110°C on fall.

Fan Control Module

The cooling fans, re-circ. pump and a.c. compressor are controlled by a relay module mounted to the top

of the passenger side wheelarch liner.  Important Note:  The a.c. relay module is identical in appearance to the
engine relay module, but the function of the two modules is different and they must not be transposed.  The a.c.
relay module A117M0038F has a brown label marked YWB100800;  The engine relay module A111E6024F has
a white label marked YWB100970.

Engine cooling radiator

Front spreader plate

Rear
mounting

Front mounting

bracket

bracket

Radiator

a.c. condenser

mounting
panel

Cooling fan

       p106

                

  

 Lotus Service Notes                                 Section KH

Page 8

If the ECM receives a signal voltage outside of the acceptable range, a default setting equating to 60°C

will be substituted, and the cooling fan energised.

KH.6 - RADIATOR FEED & RETURN PIPES

The radiator feed and return pipes are routed through the chassis main side rails, feed on the left, and

return on the right.  Each pipe is located by a grommet in the chassis front closing panel, and by a pair of
shaped foam blocks inserted into the rear end of each chassis rail.

On initial build, the water pipes are fitted before the crash structure is bonded to the front of the chassis.

A new chassis assembly is supplied with both water pipes and the crash structure pre-fitted.  If a pipe is to be
replaced in service without the crash structure being removed:

WARNING: The machined edges of the chassis extrusions and the ends of the drive fasteners can
present sharp edges and points representing a potentially serious health hazard.  It is strongly recom-
mended that industrial gloves are worn, and other suitable precautions taken to provide protection
from cuts and abrasions.

1.

Drain the coolant and remove the front clamshell (see section BR).

2.

To release the hoses from the rear ends of the water pipes requires that the fuel tank be removed.  Access
is available only via apertures in the inner walls of the chassis siderails within the fuel tank bay.  To
remove the tank refer to sub-section LJ.4.  The hoses are secured to the rear ends of the water pipes by
spring clamps requiring a suitable tool to release.

3.

Release the hoses from the front end of the water pipe.

4.

Using the access provided from within the fuel tank bay, push the water pipe forwards until obstructed by
the crash structure.  It is recommended that a suitable hole be cut in the flat vertical face of the crash
structure, adjacent to the fog lamp harness grommet, in order to allow the pipe to be withdrawn forwards.

5.

To refit, retrieve the two support foams from inside the chassis rail.  Fit the grommet into the hole in the
chassis front closing plate, and smear with rubber grease.  Feed the pipe through the access hole and
grommet, and position with 35 - 40 mm of pipe protruding.

5.

At the rear end of the pipe, fit two foam support blocks onto the pipe, and push into the chassis rail ahead
of the fuel tank bay aperture.

6.

Refit the hoses to the front and rear ends of the pipes and manipulate the pipe to check for absence of
chassis contact 'knock'.

7.

Blank off the access hole in the crash structure with a suitable grommet.

KH.7 - OIL COOLERS

Depending on market territory and date of build, cars may be fitted with either an engine mounted water/

oil heat exchanger, or a single LH front mounted air/oil cooler, or twin front mounted air/oil coolers.  The water/
oil heat exchanger or single front mounted oil cooler is entirely adequate for all normal conditions of road use,
but for cars used on closed circuit tracks or driven in a competitive manner (note; such use may invalidate
vehicle warranty), or if full vehicle performance is to be exploited for an extended period (especially in hot
ambient temperatures), it is recommended that twin front mounted coolers be fitted for optimum control of oil
temperature.

Water/oil Heat Exchanger (if fitted)

On cars so fitted, the oil/water heat exchanger is sandwiched between the oil filter and cylinder block.

Water hoses connect a tapping on the left hand side of the cylinder block to the heat exchanger, and from the