Okay here is my issue. While pulling up a hill I look down at my gauges and see my coolant temp at 186 and my oil temp at 193. This is at about 2200RPM producing 22lbs of boost or so. Not much of a load in the bed, a little less than a half ton. I have never seen it above 174 before so this was a bit of a shock. Outside temp of 48 degrees. After the hill the temp returns to a normal 170. I make a stop about 10 miles down the road. Coolant and oil level fine, nothing out of the degas bottle noted, there was no loss of power rough running noted, no smoke, no steam. Going over the coast range (1700 feet elevation change) I noted the temp up to 176 going up the hill, but what was more strange was the temp got into the low 150's going down the other side (basically an idle for a few miles at 60mph). I figure I have a thermostat issue, that explains the low temp, but what about the high temp?



What say ye all?

 

Those are not high temps at all. Nothing to worry about with those readings, if anything you are on the cool side, 185-190 is more normal. Only time to worry about temps is when oil and coolant are more then 15Deg. apart after it is warmed up. If you had any load at all thenyou are actually more then good.

 

The cool side (low 150's) is what had me thinking about the thermostat, it has never been that cool before just because I was going down hill. I have been over the coast range here in Oregon a dozen time or so in this truck, both warmer and much colder temps before and never had coolant temps that low before. I also never saw a temp spike up that high before today. The average spread in oil/coolant temp is 4-8 degrees average with 11 being the largest, one time, and for only a few minutes on a hard pull.

 

The oil temp is always going to be higher, the oil cooler uses the engine coolat to cool the oil down so when you are up on the boost and engine i working harder the oil is going to get hotter. the turbo, when building more boost, also heats the oil up pretty good. as far as the high side you are fine, I know my buddies truck as well as mine both run right around 190Deg normally. Yes I think you might have a thermostat that is sticking open if you see 150deg. after truck is warmed up.

 

I went ahead and bought one, dang $35.00 for a thermostat just does not seem right but I guess it is what it is.

 

Replaced my thermostat today and it sits right on 190 now. This is perfect. It will be nice for my engine to actually run at the temp its designed to run. I wonder how much fuel I wasted running at 170 or less with a screwed up thermostat

 

Always glad when someone reports back about a fix, yeah you burned a little more dino oil running cooler temps, hopefully you will start saving some money for other things now.