Engine Oil Temps - Sorry For This Thread!

[wildcatgoal]

I recently installed a Mishimoto oil cooler and I have a temp sensor in the sandwich plate, which is supposed to have a 185* thermostatic valve on it such that, unless the oil reaches that temperature, it will bypass the oil cooler.

My oil temp gauge, driving on the highway in 6th, indicates 140-150*. If I drop to 5th, and run at the same speed (just at a higher RPM), I can get the oil to go to about 160-170 per my gauge. If I drop to 4th, running at the same speed (just a much higher RPM now), I can get the oil to cross 180, maybe hit 190. Can't tell exactly because it's an analogue gauge with 20* gaps between labeled tick marks. But if I switch back to 6th and cruise at the same speed, the temp drops fairly quickly back down to 140-150* (per the gauge). The temp never really goes lower than that once the engine is warmed. At idle, oil temps slowly climb but don't seem to cross 190*, as far as I've paid attention.

My understanding is that I should be around 180-220 degrees for oil, and ideally 212*. My Dodge Durango, if its oil temp gauge on the dash is legitimate vs. inferred (I have no idea), states 212* cruising on the highway. My Mustang's aftermarket gauge indicates 140-150* on the same drive, on the same day, just in the opposite direction.

I realize that putting the sensor in the oil pan might yield a different reading, but I'm a little concerned I'm seeing 140-150* when you'd think I'd be at at least 185* before the oil cooler ever sees any oil flow. What gives here? What am I not understanding? Or do I have a bad sandwhich plate or temp sensor? The gauges are made by Glowshift. Not god's gift to gauges, but I have no reason to believe the gauge is faulty at this point.

Sponsored

 

[HoosierDaddy]

I'm assuming you are referring to an aftermarket oil temp gauge. But if by some wild chance you are talking about a GT350 oil temp gauge you installed in a GT, that would only display a calculated oil temp which I would guess an aftermarket oil cooler and thermostat would not be factored into the calculations.

 

[wildcatgoal]

I don't have the GT350 gauge in the car anymore since I have an aftermarket gauge. GT dash has an oil temp gauge (just doesn't say value, just a dial). That's what I'm referring to.

 

[thehunterooo]

My GT350 cluster usually reads out in the 210~ range for the engine oil temp.

 

[ahl395]

Just a guess, but it probably makes a difference where it's measuring the oil temp. Does the aftermarket sensor measure after the factory oil cooler? That could explain the lower temps.

Only other thing that comes to mind is maybe the thermostatic plate is stuck open and oil is always flowing the the cooler (and becoming cooler than usual).

 

[wildcatgoal]

I was told today by a friend that these end up measuring oil temp after the cooler, which is kind of useless to me. I have a message to [MENTION=9961]Mishimoto[/MENTION] about it but will call Monday.

 

[EFI]

I was told today by a friend that these end up measuring oil temp after the cooler, which is kind of useless to me.

That's probably what's happening. You should ideally be measuring the temp of the oil in the sump, as both on the way out and on the way in the #s will be skewed.

 

[wildcatgoal]

So that would require tapping the oil tank? Might as well just get a better oil tank that has sensor bungs already if I'm going to be fooling around there.

For now I'll add 40* to the gauge temp. 40* reduction I believe is Mishimoto's claim. Good enough...

 

[EFI]

Can you put the sensor on the outlet? That should actually be alot closer to the sump temp than the other way around.

I believe the way it works is that the oil pump pulls the oil from the pan, out to the cooler, back through the filter and on to the engine. If that's the case, then the outlet temps should be very similar to those in the sump as there isn't a major increase in temp as the oil gets pressurized by the pump.

Sponsored