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Dodge Nitro. Manual - part 47

LUBRICATION

DESCRIPTION

LUBRICATION

The lubrication system is a full flow filtration pressure feed type.

OPERATION

LUBRICATION

Engine Lubrication Flow Chart - Block: Table 1

Engine Lubrication Flow Chart - Cylinder Heads: Table 2

FROM

Oil Pickup Tube

Oil Pump

Oil Filter

Block Main Oil Gallery

1. Crankshaft Main Journal

2. Left Cylinder Head*

3. Right Cylinder Head*

4. Counterbalance Shaft Rear Journal

Crankshaft Main Journals

Crankshaft Rod Journals

Crankshaft Number One Main Journal

1. Front Timing Chain Idler Shaft

2. Counterbalance Shaft - Front Journal

3. Both Secondary Chain Tensioners

Left Cylinder Head

Refer to Engine Lubrication Flow Chart - Cylinder
Heads: Table 2

Right Cylinder Head

Refer to Engine Lubrication Flow Chart - Cylinder
Heads: Table 2

* The cylinder head gaskets have an oil restrictor to control oil flow to the cylinder heads

FROM

Cylinder Head Oil Port (in bolt hole)

Diagonal Cross Drilling to Main Oil Gallery

Main Oil Gallery (drilled through head from rear to
front)

1. Base of Camshaft Towers

2. Lash Adjuster Towers

Base of Camshaft Towers

Vertical Drilling Through Tower to Camshaft
Bearings**

Lash Adjuster Towers

Diagonal Drillings to Hydraulic Lash Adjuster
Pockets

** The number three camshaft bearing journal feeds oil into the hollow camshaft tubes. Oil is routed to
the intake lobes, which have oil passages drilled into them to lubricate the rocker arms.

2007 Dodge Nitro R/T

2007 ENGINE 3.7L - Service Information - Nitro

Fig. 138: Lubrication Oil Flow
Courtesy of CHRYSLER LLC

1 - OIL FLOW TO RIGHT CYLINDER HEAD
2 - CYLINDER BLOCK MAIN OIL GALLERY
3 - LEFT CYLINDER HEAD OIL GALLERY
4 - OIL FLOW TO BOTH SECONDARY TENSIONERS
5 - OIL FLOW TO LEFT CYLINDER HEAD
6 - OIL PRESSURE SENSOR LOCATION
7 - OIL FLOW TO COUNTER BALANCE SHAFT
8 - OIL PUMP OUTLET TO CYLINDER BLOCK
9 - OIL PUMP

2007 Dodge Nitro R/T

2007 ENGINE 3.7L - Service Information - Nitro

Oil from the oil pan is pumped by a gerotor type oil pump (9) directly mounted to the crankshaft nose. Oil
pressure is controlled by a relief valve mounted inside the oil pump housing.

The camshaft exhaust valve lobes and rocker arms are lubricated through a small hole in the rocker arm; oil
flows through the lash adjuster then through the rocker arm and onto the camshaft lobe. Due to the orientation
of the rocker arm, the camshaft intake lobes are not lubed in the same manner as the exhaust lobes. The intake
lobes are lubed through internal passages in the camshaft. Oil flows through a bore in the No. 3 camshaft
bearing bore, and as the camshaft turns, a hole in the camshaft aligns with the hole in the camshaft bore
allowing engine oil to enter the camshaft tube. See Fig. 138. The oil then exits through 1.6mm (0.063 in.) holes
drilled into the intake lobes, lubricating the lobes and the rocker arms.

DIAGNOSIS AND TESTING

ENGINE OIL LEAK

Begin with a thorough visual inspection of the engine, particularly at the area of the suspected leak. If an oil
leak source is not readily identifiable, the following steps should be followed:

1. Do not clean or degrease the engine at this time because some solvents may cause rubber to swell,

temporarily stopping the leak.

2. Add an oil soluble dye (use as recommended by manufacturer). Start the engine and let idle for

approximately 15 minutes. Check the oil dipstick to make sure the dye is thoroughly mixed as indicated
with a bright yellow color under a black light.

3. Using a black light, inspect the entire engine for fluorescent dye, particularly at the suspected area of oil

leak. If the oil leak is found and identified, repair per service information instructions.

4. If dye is not observed, drive the vehicle at various speeds for approximately 24 km (15 miles), and repeat

inspection.

If the oil leak source is not positively identified at this time , proceed with the AIR LEAK
DETECTION TEST METHOD.

Air Leak Detection Test Method

1. Disconnect the breather cap to air cleaner hose at the breather cap end. Cap or plug breather cap nipple.

2. Remove the PCV valve from the cylinder head cover. Cap or plug the PCV valve grommet.

3. Attach an air hose with pressure gauge and regulator to the dipstick tube.

4. Gradually apply air pressure from 1 psi to 2.5 psi maximum while applying soapy water at the suspected

10 - OIL FLOW TO CRANKSHAFT MAIN JOURNALS
11 - CRANKSHAFT MAIN BEARING JOURNALS
12 - RIGHT CYLINDER HEAD OIL GALLERY

CAUTION: Do not subject the engine assembly to more than 20.6 kPa (3 PSI) of

test pressure.

2007 Dodge Nitro R/T

2007 ENGINE 3.7L - Service Information - Nitro

source. Adjust the regulator to the suitable test pressure that provide the best bubbles which will pinpoint
the leak source. If the oil leak is detected and identified, repair per service information procedures.

5. If the leakage occurs at the rear oil seal area, refer to INSPECTION FOR REAR SEAL AREA

LEAKS.

6. If no leaks are detected, turn off the air supply and remove the air hose and all plugs and caps. Install the

PCV valve and breather cap hose.

7. Clean the oil off the suspect oil leak area using a suitable solvent. Drive the vehicle at various speeds

approximately 24 km (15 miles). Inspect the engine for signs of an oil leak by using a black light.

INSPECTION FOR REAR SEAL AREA LEAKS

Since it is sometimes difficult to determine the source of an oil leak in the rear seal area of the engine, a more
involved inspection is necessary. The following steps should be followed to help pinpoint the source of the leak.

If the leakage occurs at the crankshaft rear oil seal area:

1. Disconnect the battery.

2. Raise the vehicle.

3. Remove torque converter or clutch housing cover and inspect rear of block for evidence of oil. Use a

black light to check for the oil leak:



Circular spray pattern generally indicates seal leakage or crankshaft damage.



Where leakage tends to run straight down, possible causes are a porous block, camshaft bore cup
plugs oil galley pipe plugs, oil filter runoff, and main bearing cap to cylinder block mating surfaces.

4. If no leaks are detected, pressurize the crankcase as described in AIR LEAK DETECTION TEST

METHOD.

5. If the leak is not detected, very slowly turn the crankshaft and watch for leakage. If a leak is detected

between the crankshaft and seal while slowly turning the crankshaft, it is possible the crankshaft seal
surface is damaged. The seal area on the crankshaft could have minor nicks or scratches that can be
polished out with emery cloth.

6. For bubbles that remain steady with shaft rotation, no further inspection can be done until disassembled.

REAR CRANKSHAFT OIL SEAL AREA LEAKS

CAUTION: Do not exceed 20.6 kPa (3 psi).

CAUTION: Use extreme caution when crankshaft polishing is necessary to

remove minor nicks and scratches. The crankshaft seal flange is
especially machined to complement the function of the rear oil seal.

2007 Dodge Nitro R/T

2007 ENGINE 3.7L - Service Information - Nitro

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