The cast aluminum oil pan is used as a structural
member of the powertrain by providing mounting
bosses for both the transaxle case and mounting
brace located at the extension housing of the
transaxle. The oil pan incorporates riveted internal
oil baffle plates and seals to the lower crankcase
with a silicone gasket. The oil pan also provides
mounting for an oil level sensor.

The oil sump pickup is fastened to the oil pump
by a bolt and nut to one stud-headed main
bearing bolt. A silicone o-ring seals this joint on
the suction side of the oil system. The engine oil
pump is a gerotor design mounted to the lower
crankcase behind the engine front cover. The
inner gerotor element is driven by splines on the
crankshaft timing chain sprocket which, in turn, is
driven by a pin in the crankshaft. As the pump
rotates, oil is drawn from the sump through the
sump pickup to the pump inlet. Oil compressed
by the pump enters the lower crankcase and is
routed to the oil filter inlet passage in the oil pan.

The oil filter bypass valve is located in the lower
crankcase and is not serviceable. The valve will
route oil directly from the filter inlet to the filter
outlet should the filter become plugged.
3.5L Engine Oiling Systems Operation

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After passing through the filter, the oil is directed to the main
longitudinal gallery in the lower crankcase. Each of the four
crankshaft bearing feeds from the main gallery through passages
in the lower crankcase which intersect passages in the upper
crankcase half of the crankshaft bearing saddle. Drilled passages
in the crankshaft between the crankshaft bearing journals and the
connecting rod journals providing lubrication for them and
ultimately provide splash lubrication for the cylinder walls. The
number one and four crankshaft bearing oil feed also provides
lubrication to the respective balance shaft bearings. Oil leaking
past the front balance shaft bearing lubricates the primary timing
chain via oil splash. The primary timing chain tensioner is fed
through an oil transfer tube.

From the front balance shaft bearing, oil is fed through passages
in each bank of the crankcase and into each cylinder head where
longitudinal passages supply each hydraulic lash adjuster and
the camshaft journals. Oil returns to the sump either through the
cam chain area or by way of cast passages on the outside walls of
the cylinder heads, cylinder block and oil pan.