Coolant temp compared to Oil temp?

[Xtc6k]

I have a Coolant temp gauge that shows the the temperature of the coolant, but no oil temp gauge.
I want to know if coolant temp has any direct correlation to oil temp. Is the coolant suppose to be X'degrees cooler than the oil? etc.

 

[bullwinkle]

Depends on whether you have an oil cooler or turbocharger to heat up or cool off the oil-usually oil temp is higher than coolant, but no way to tell without a gauge or knowing what engine you're running.

 

[chubbs1]

Yeah, there are just too many variables, the only way you can know for sure is a good oil temp gauge. I mean if it is 95F outside and you take the vehicle for a 20 min. Highway run it is going to be fully up to temp, but for short distances no way to tell with accuracy.

 

[A_Harman]

It generally takes a lot longer for oil to heat up than it does for the coolant. Most passenger cars don't have oil coolers, and there is no thermostat to regulate oil temperature. In normal daily-driver usage, oil temperature will eventually get up to coolant temperature, and if engine speed is kept low, the oil will stay at 180-200F. If you are driving hard with the engine speed high, after about 10-15 minutes, oil temperature can get up to the 220F range. None of these temperatures are of concern. It is actually better to get the oil temperature above 200F for extended periods so that the water that comes into the crankcase from combustion products can be boiled off. In the cases where oil temp never gets above 150F, such as in short-interval winter driving, the oil actually ages more quickly. I consider oil temperature in the range of 180-240F to be normal operating range.

 

[SteveSRT8]

Way too general, some engines heat the oil quickly if they have piston cooling jets. Some, like GM don't in most applications.

I've seen 300 degrees at the track. Normal temp in town is 210-220 with a 177 tstat and aftermarket tune.

 

[TallPaul]

Generally the coolant will come up to full operating temp in about 2-3 miles, but the oil will take up to 15 miles, so there is a big lag. I have an accurate oil pressure gauge (mechanical) and so can tell when it is at operating temp as the pressure settles from a cold value of 50 psi to a hot value of 40 psi, both at 2000 rpm.