I have a 180 degree MOCAL oil thermostat correctly installed near the engine for my 12" x 12" front mounted oil cooler. The cooler does a fantastic job of keeping oil temps just above 180 even on the hottest track days.

The problem is driving around town. The oil temp will not go higher than 135 even after driving for an hour. I blocked off the intake to the cooler this morning and managed to get it up to 150, but no further. Ambient air temp this morning was about 55 deg F.

I understand that the thermostat will bypass some even when cold, but it seems to me that it is bypassing a lot more. Just curious what others have seen in their experience.

I'm close to putting a small damper and actuator that would control when the cooler gets full flow based on an existing on/off switch I have on the engine that closes at 180 deg.

Doesn't the engine case have an thermostat on it?

This is a 914/6 GT clone. The engine does have an oil thermostat for the on engine oil cooler. My oil temps were 270 without the front mount cooler. The front mount cooler cools the scavenged oil before returning it to the oil tank.

Maybe the thermostat on the engine case has failed in the open position allowing the engine cooler to over cool the engine oil?

Use an infrared thermometer to check temps all over the motor and lines.
You'll find out what's what.


KT