Air in my oil cooler=higher oil temps?
 

I have been having freakishly high oil temps on my recently (1100 miles) rebuild TII. Could this be caused by air trapped in the oil cooler?

THe oil temp rises the longer I drive it. It will initally settle around 170, but the longer I drive it the higher it gets. It gradually rise to about 210 in 20-30 minutes of light driving. A couple times it has shot up to 230 while idleing at a stoplight. That is way to high!

Before the rebuild my temps would range from 160-190 and would only get above 200 under extreem boosting conditions. I havent even boosted my rebuilt engine yet. Coolent temps never rise above 185 during any of this.

Could this be from air in the oil cooler? Could it be caused by anything else?

Thanks for any help in advance.
Steve

Did you remove the oil cooler thermostat?

What do your water temps do?

I doubt it.
The oil system runs at pretty high pressure, so bubbles cannot easily form.

Did you double-check your ignition timing?
Overly advanced ignition timing can heat the oil up.

Are you running the engine floorpan?
If this isn't intact, airflow tends to run under the oil cooler.


-Ted

Are you talking about the thermal pellet in the e-shaft? I replaced that with a bypass pellet. If your talking about something else.... what is it?

Water temps are normal as they always have been. 180-185 constant

I was thinking that when I refilled the engine with oil after the rebuild that air could have gotten trapped in the oil cooler because it had drained when the engine was out.

I did not double check the timing. Can that easily get thrown off doing a rebuild? I didn't purposely change it. I have no driveability issues. revs smooth to 4k, idles strong at 750 rpms.

I took the undertray off when I got the car. Drove for a year and a half without it with no problems. So no undertray, but there never has been.

Sounds like I should check timing.

Ted, I'm pretty sure where you are going with this but can you elaborate?

He's talking about the thermal bypass in the bottom of the oil cooler. It opens when the oil's cold so that oil doesn't flow through oil cooler's core. It closes at ~150degF to force oil through the core. It doesn't seem to fail often, but if it has then you basically have a non-functioning oil cooler.

Check it as per the instructions in the FSM.

Thanks NZ, I didn't know there was such a thing in the oil cooler.

So the theory is that if it fails, then it fails open allowing oil to bypass the oil cooler.

UPDATE

I put my under engine tray back on. This seemed to make a difference at times. Mainly light driveing under 45mph. Temps stay between 170-200 under these conditions.

I still have a huge problem with driving on the highway. Crusing at 60-70 MPH causes oil temps to vary from 200-215. Going up hills at these speeds causes spikes in the temperature up to as high as 225.

So the main problem remains. The longer I drive the higher the temps get.

I have looked at the FSM and I plan on pulling off my oil cooler soon to check the bypass valve. I hope it is as simple as this. If not, I will be at a lose for what to do.

Steve

Did you restab the CAS when you were done with the engine and ready to put it back in? If not the timing could essentially be anywhere. Once the front cover or CAS is removed timing gets fucked and you need to restab it.

Nothing more than the basic stab. No timing light adjustment. I should really do that. I initailly doubted that it could run so smooth with the timing being significantly out. Who knows at this point though. The idle does bubble a bit.

Just seems odd that if the timing was close enough for the engine to run smoothly that it would also be off enough to heat up the oil so much.

Are you serious?

No timing light? Go buy one. It is about 20 dollars.

James

whats condition of your OIL, any smell of gas in oil?
from fresh rebuild, your oil could be diluted by fuel and might not work as good as supposed to

Oil looks clean. I haven't noticed a gas smell in it. Changed it after 500 miles. Will again at 2000. Right now I'm sitting at 1700 miles.

I'd check your timing to make sure it's all okay and do remember to verify the trailing is lined up too, just because leading is lined up doesnt necessarily mean trailing is and I would know haha.

any oil temps over 200 is very bad for a rotory.... sounds like the coolers bad

I have a feeling my gauge might have crapped out on me. I will be setting the timing today and checking the gauge for accuracy.

PROBLEM SOVLED.

Today I checked the timing, it was off by a significant amount. Set it, runs really really good now.

Next the gauge! It is funked up! My oil temp is fine, the gauge sucks a big one. It was the gauge the whole time. I'm gonna try to fix it.

Don't bother trying to fix it, just get a proper aftermarket one instead.