Oil pump (21) is mounted to the bottom of the cylinder block
inside the oil pan. The pump pulls oil from oil pan (20) and
pushes the oil through passage (10) to oil cooler (19). Oil then
flows through oil filter (18). Clean oil from the filter enters
turbocharger oil supply line (15) and main oil gallery (6).
Engine - Right Side
(15) Turbocharger oil supply line. (16) Oil filter bypass. (17)
Oil cooler bypass. (18) Oil filter. (19) Oil cooler. (22)
Turbocharger oil return line.
The main oil gallery distributes oil to main bearings (14), piston
cooling jets (11) and camshaft bearings (5). Oil from gallery
(6) also exits the front of the block and enters passage (7)
casting the front housing.
Front housing passage (7) splits the oil flow in two directions.
At the upper end of passage (7), oil is directed back into the
block and up to cylinder head oil gallery (3). At the lower end
of passage (7), oil enters passage (9). This passage sends oil
to the oil pump housing to lubricate the oil pump idler gear (and
front bearings of the balancer shafts on 4 cylinder engines).
Oil from the front main bearing enters passage (8) to lubricate
the camshaft idler gear bearing. Oil passages in the
crankshaft send oil from all the main bearings to the
connecting rod bearings.
On the 4 cylinder engine, some of the oil going to the rear main
bearing is directed out the rear face of the block to passage
(12) in the crankshaft seal carrier. Oil is then directed into
block passage (13) and down to the rear balancer support to
lubricate the rear bearings of the balancers. A passage in the
balancer shafts now carries the oil from the rear balancer
bearings to the intermediate bearings of the shafts.
Passages (4) send oil from the camshaft bearings to a short
passage (9) in the side covers. The oil then enters a hole in
the shafts of the pushrod lifters to lubricate the lifter roller
Engine - Left Side
(1) Governor oil supply line. (23) Crankcase breathe (24)
Location of oil passage for pushrod lifters (inside each side
cover). (25) Plug.
Cylinder head oil gallery (3) provides flow to governor oil
supply line (1) and rocker arm supports. Holes in the rocker
After the lubrication oil has done is work, it goes back to the
engine oil pan.
There is a bypass valve in the oil pump. This bypass valve
controls the pressure of the oil coming from the oil pump. The
oil pump can put more oil into the system than is needed.
When there is more oil than needed, the oil pressure increases
and the bypass valve will open. This allows the oil that is not
needed to go back to the suction side of the oil pump.
With the engine cold (starting conditions), bypass valves (16
and 17) will open and give immediate lubrication to all
components when cold oil with high viscosity causes a
restriction to the oil flow through oil cooler (19) and oil filter
(18). The oil pump sends the cold oil through the bypass
valves around the oil cooler and oil filter to the turbo supply line
and the main oil gallery in the cylinder block.
When the oil gets warm, the pressure difference in the bypass
valves decreases and the bypass valves close. Now there is a
normal flow of oil through the oil cooler and oil filter.
The bypass valves will also open when there is a restriction in
the oil cooler or oil filter. This action does not let an oil cooler
or oil filter with a restriction prevent lubrication of the engine.