johnsopa

I am trying to understand the oil flow, temperature sensing and thermostats in our cars. My car is running hotter than last summer.

Here are the things I understand so far:

1. There's an oil temperature sender on the right side crankcase -- this feeds the dash oil temp gauge.

2. There's an oil cooler under the front right bumper (passenger side in US).

3. There's an oil temp microswitch on the oil cooler that sets the oil cooler fan to off-low-high.

Where are the thermostat(s) that open/close oil flow in this system -- particularly to or from the oil cooler?

At what temperatures (or other conditions) do these thermostat(s) open/close?

At what temperatures do the microswitch on the oil cooler go from off to low and from low to high?

My oil cooler fan has not been going on at all. To try and diagnose my seemingly high temps (around 225 - 250 or 9:30 to 10:00 in city with A/C and stop-and-go) I disconnected the oil cooler microswitch. Sure enough, the fan is now on permanent high and the temp gauge goes to 9:00 (when I assume a thermostat opens) then drops to 8:00/200 during stop-and-go driving.

I'm guessing that my microswitch is bad.

GeoT3

John, I believe the oil temp thermostat is beneath the oil tank and is where the main oil filter is located - it has 2 hoses connected to it and it travels to the front oil cooler. on my car, the oil thermostat opens at 195 deg. +/-. when it does open up I can see the temp. gauge drop to below 194 degree mark and slowly raise to 194 degree mark again. it rarely does go above 9:00 position with A/C on in traffic thus far. I live in NJ where it gets humid and quite hot. on my car the front oil cooler fan does not come on until my temp gauge is slightly above 9:00. there is a aux. cooling fan/ventilation fan that does come on after I shut the engine off while the temp gauge is slightly above 9:00 to cool the engine down. hope this helps.