I was wondering if someone could tell me if the oil coolers work to just cool the engine oil temps or if they also work in conjunction with the turbo system?

 

The inside of the engine rotors are cooled by oil. Therefore, the oil would overheat if there were no oil cooler(s). If the oil were too hot, the turbos would suffer from that, as well as the rest of the engine.

 

They cool the oil which in turn cools both the turbos and engine.
Art

 

Ya, its all the same oil. The turbos arent on their own oil source while the engine has its seperate one

 

My aftermarket oil thermostat failed recently and the oil wasn't flowing through the coolers. My oil temp sensor is mounted in the line that feeds the engine, which would be after the coolers (if my thermostat was sending the oil through them). I have a large single turbo with a "dry" center (no coolant running through the turbo center section), thermal coated rotors (might lower oil temps slightly), and the Crooked Willow dual 19-row Mocal coolers. I was running non-synthetic 20W-50 oil.

With the broken thermostat, my oil temps were 210-ish in light cruising, which is about the upper limit of "safe" oil temps. I am still breaking in the new engine, so I wasn't boosting or revving much over 4000 RPM. I was also doing most of the driving at night in ~60F weather. Coolant temps were around 178F. The OT gauge was holding a peak of 219F over a mix of gingerly driving in the highway and city, in day and night, with abmient temps of no more than 75F (probably not even that high). What I learned from this is that without oil coolers, your oil is going to cook. I wasn't even driving hard, and the weather was mild.

I replaced the oil thermostat, and my oil temps under the same highway-cruising conditions are now 140F. Coolant temps have also dropped to 172F (I have some holes in the thermostat, hence the lower-than-180F temps). My OT gauge is currently holding a peak temp of 177F, which includes a mix of day and night, highway and city driving, slightly more aggressive than my driving when the oilstat was broken. There are no fans on the oil coolers, so the oil temps go up if you are sitting in traffic (165F for city driving seems to be about average).

-Max