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3.7L Engine - Service Information: Maintenance Dodge Nitro I

Mechanical 2 illustrations ~266 words

LUBRICATION

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

FROMTO
Oil Pickup TubeOil Pump
Oil PumpOil Filter
Oil FilterBlock Main Oil Gallery
Block Main Oil Gallery1. Crankshaft Main Journal
2. Left Cylinder Head*
3. Right Cylinder Head*
4. Counterbalance Shaft Rear Journal
Crankshaft Main JournalsCrankshaft Rod Journals
Crankshaft Number One Main Journal1. Front Timing Chain Idler Shaft
2. Counterbalance Shaft - Front Journal
3. Both Secondary Chain Tensioners
Left Cylinder HeadRefer to ENGINE LUBRICATION FLOW CHART - CYLINDER HEADS: TABLE 2
Right Cylinder HeadRefer to ENGINE LUBRICATION FLOW CHART - CYLINDER HEADS: TABLE 2
* The cylinder head gaskets have an oil restricter to control oil flow to the cylinder heads

ENGINE LUBRICATION FLOW CHART - BLOCK: TABLE 1

FROMTO
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 TowersVertical Drilling Through Tower to Camshaft Bearings**
Lash Adjuster TowersDiagonal 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.

ENGINE LUBRICATION FLOW CHART - CYLINDER HEADS: TABLE 2

Scheme 34

Scheme 34
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
10 - OIL FLOW TO CRANKSHAFT MAIN JOURNALS
11 - CRANKSHAFT MAIN BEARING JOURNALS
12 - RIGHT CYLINDER HEAD OIL GALLERY

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. (Scheme 34) The oil then exits through 1.6 mm (0.063 in.) holes drilled into the intake lobes, lubricating the lobes and the rocker arms.

Scheme 35

Scheme 35: CHECKING ENGINE OIL PRESSURE
1 - BELT
2 - OIL PRESSURE SENSOR
3 - OIL FILTER
4 - ELEC. CONNECTOR
  1. Remove oil pressure sending unit (2) and install gauge assembly C-3292. (Scheme 35)
  2. Run engine until thermostat opens.
  3. Oil Pressure: Curb Idle - 25 kPa (4 psi) minimum 3000 RPM - 170 - 758 kPa (25 - 110 psi)
  4. If oil pressure is 0 at idle, shut off engine. Check for a clogged oil pick-up screen or a pressure relief valve stuck open.