Running 65-70 miles an hour, 3:73's with 33 inch tires, 30* ambient temps, and an 8 foot Western plow hanging on the front a little low for air flow. Is this an okay temp for the oil?

 

Normal is 190 - 235 @ Service Manual

 

I think your fine. In fact, its probably a good thing. You really don't want the oil any cooler then that.
Remember, the International T-Stat is 203deg, and oil usually runs hotter then the coolant. I think anything under 240* is nothing to worry about. Even a little more is probably ok, at least if you r running Rotella T6 or another full synthetic.

 

Stock stat is around 195F. I would expect it to be within 10 degrees of that on the upside when warm.

 

Yes, that is about normal. The oil-coolant delta should be in the 5-10 degree range.

 

Thanks, I thought it was okay, but wasn't sure. Running around tonight not on the highway as much 25-28 degree ambient and without the plow had 196* most of the ride.

P.S.-and I just realized I put 200* in the title and meant to put 220* but I guess we are still good.

 

Hey Jason, you don't really want the oil temp above 210 anything above that for a short time won't kill anything.

 

There's a pretty interesting read on an oil forum I visitation time to time. Oil doesn't even begin to break down from high temps until long past where these trucks even get to while towing heavy. I used to worry but now I don't even stress unless it gets to 240* and won't come down. Even then, I just pay attention and make sure it doesn't get out of control.

 

what weight of oil are you using?

 

I have to tow uphill in the summer to reach 210 - and the fan is going all rocket on me when I hit that. That's with coolant cooling the engine, not ambient temps.

 

My truck used to only get to about 225* when towing heavy up a grade for a while. It has since gotten worse even with a cooler thermostat. I am doing the O-Rings on my oil cooler today. I am hoping I find a blockage of some sort to explain these higher temps. Just driving down the highway empty will see 200-205 these days. Something is amiss. Again, I don't stress over it too much,. I just know it is not the norm for my truck so I tend to think something is not right.

 

Do you hear the rocket noise of the cooling fan when it gets that hot?

 

I don't, but I think that is because my coolant temps are low enough. I run a 180* thermostat from Riff Raff, so from my understanding, the fan clutch isn't seeing a hot enough temp to engage. It did engage one time this last towing trip going up a long grade, but now you have me wondering... When I try to spin it with the truck off, it has plenty of resistance which tells me it isn't burnt. Am I doing that wrong? I forget. My coolant temp stays at the N or just below it. I know that's an idiot gauge, but just based on previous behavior of running hotter until I fixed the thermostat, it tells it's running pretty cool.

 

I've monitored quite a few trucks back in the day. It's common for oil temps to rise to the 220's-230's when the engine is being "worked" in certain ways.

It's nothing to worry about. That's just normal operation. Gets even hotter when running dual HPOP's. I saw temps on my old truck get close to 240 degrees back when I ran Termys, and that was just an empty truck going uphill at high altitude.

Something to chew on: The new 6.7L's see oil temps reaching in the 250's when towing. And that's perfectly normal operation for those motors.

 

I guess I'm just used to my lean 190 and very close coolant temps.