Oil Flow -- Es33Pf - Polaris Trail Blazer Service Manual

ENGINE
Lubrication/Oil Flow - ES33PF
Oil Flow - - ES33PF
The ES33PF engine is equipped with a thermostatically controlled valve that directs oil returning to the tank
through a cooler when the oil is hot. Valve operation is described below. The chart on page 3.44 describes the
flow of oil through the ES33PF engine and oil cooler. Beginning at the oil tank, the oil flows through a screen fitting
in the bottom of the tank and into the oil supply hose. The feed side of the oil pump draws oil through the hose
and into the crankcase inlet oil passage, and then pumps the oil through another passage to the one way valve.
(Note: The one way valve closes under light spring pressure when the engine is off to prevent oil in the tank from
draining into the crankcase. The valve requires very little maintenance). After passing through the one-way valve,
oil is pumped through a delivery pipe to the oil filter. If the oil filter is obstructed, a bypass valve contained in the filter
allows oil to bypass the filter element.
At this point, the oil is diverted in two directions. Oil is supplied to the camshaft through the left front cylinder stud,
and an oil passage in the head. Oil enters the camshaft through the PTO (L) journal. The camshaft journals, cam
lobes, and rocker arms are lubricated through holes in the camshaft. The oil lubricates the cam chain and sprocket
and drains to the sump.
The other oil path from the filter leads through a delivery pipe to the crankcase main oil gallery, which leads to
the stator plate oil passage. Here it passes through the slotted friction bearing (located in the stator plate) into
the crankshaft. An oil seal on the stator plate prevents oil from entering the stator/flywheel area. Oil travels
through the crankshaft to the crank pin, lubricating the connecting rod large end bearing directly. Oil also passes
through an oil jet (drilled orifice) in the end of the crank pin to the PTO end main bearings and counterbalancer
gears.
Residual oil from the lubrication of the crankshaft and connecting rod indirectly lubricates the cylinder wall, piston,
rings, connecting rod small end bearing, piston pin, oil/water pump drive gears, cam chain and drive sprocket,
and Magneto end crankshaft main bearing.
After returning to the engine sump, oil is drawn by the scavenge pump out of the sump and through a screen.
Scavenged oil is directed through another crankcase oil passage through the outlet hose to the thermo-valve,
and directly back to the oil tank. When the oil reaches a pre-determined temperature, the thermo-valve opens
to direct oil through the cooler, and then back to the tank
Oil Cooler Thermo Valve
4/99 3.44 Polaris Sales Inc.