My GMC oil cooler will only let the engine temp. to reach 185.Am I loosing gas mileage?

Question

If it could reach 195 degrees wouldn`t it get better gas mileage?

Answer 1

yes

Answer 2

Not at all.
Gas mileage isn't affected by temperatures over 175.
an engine must reach normal operating temperature so the car computer can go into "closed loop mode". this is when the car usually reaches 170 or more. at 195, manufacturers deem this to be the optimum temperature for the air/fuel mixture.
I run 185 in my truck, running a bit cooler helps in many ways, gives me like 1-2 HP more, my engine runs a bit cooler so overheating isn't as likely as my thermostat opens sooner, when I tow and haul things, my engine won't heat up as fast.

thermostats aren't perfect, a 195 degree stat will open around 195, rarely exactly on.
when the computer is in open loop mode, when things are closed, the engine burns more fuel because the computer doesn't sense the regular operating temp.
the oxygen sensor plays a pretty vital role in this moreso.

Answer 3

Motor oil coolers have no affect on the actual motor temperature. That is controlled by the coolant system and the working opening temp. of the thermostat. Yes, fuel mileage is affected by a lower temp. That's why they usually run the motor close to 100 C or 212F. Change the thermostat and see what the difference is. Honestly though, it won't make much of a difference.

Answer 4

The engine temp is measured at the thermostat, the thermostat is what actually controls the overall temp. you may be getting some benefit from the oil cooler, but not much...UNTIL you tow a big trailer up a long hard hill!!

So get the 195 degree thermostat if you are concerned. Your heater will work better .....

heres a good read on Oil Myths and facts...
http://www.nordicgroup.us/oil.htm