The motor thermostat bypasses the engine cooler until the oil heats it, I think. This should happen pretty quickly. You can see the cooler from in front of the right rear wheel and point your IR thermometer at it. I don't get any flow thru my front cooler until I drive for awhile.

Not dumb at all, but I don't think this is the case. I'm seeing the housing temperature rise through the 180's, 190's, past 200, and finally 215 or so over the course of several minutes. The element popped open quickly in a pot of water starting at around 185. I would think I would see SOME heating of the front lines in the period I'm seeing the temp rise at the housing. Keep in mind also that the last time I drove the car I saw 250(!) on the gauge and still no heat in the front lines..

Hot engine............
 

Try taking the pistons and springs out of the external thermostat and just put the plugs back on. Then crank it up and let it idle. If the problem lies outside of the thermostat, this will help you to find the real issue.

Is it possible for the thermostat to open but not close the path back to motor . The oil could flow to cooler and motor but it would take least resistance shortest path back to motor. Symptoms would be very similar to what you have.

i have 1986 - same as yours and it seems like it has same issue .... maybe it is normal.
Since i can not drive the car - working on body/suspension, after changing oil I let the car idle for about 15-20 minutes and noticed that oil cooler/lines after thermo were cold.
Maybe it takes more to warm it up ( my temp gauge did not move much either)
Looking for some more ideas :)
stan

Yours is different and that's normal, you will not see the gauge go up until you start driving. the issue on this thread is that his temperature shoots up within 10 minutes or so.

Fred, thanks, but I think if I just removed the guts from the thermo housing I would be trying to pressurize the front cooler inlet and outlet, and the 'exit to tank' ports all at the same time, correct? And would probably just get flow to the tank as this would be the easiest path?

I believe this photo was originally provided by Grady Clay, RIP


http://forums.pelicanparts.com/uploa...1493321729.jpg

Sent you email Len.

Thanks

Time for an update.

The hose I got made up locally to bypass the front oil cooler had the wrong fittings - M30 x 2.0. I think the correct size is M30 x 1.5? I took Len up on his generous offer of the loan of his test loop. He shipped it to me super-fast.

While I was waiting, I went ahead and did some more checks to try to figure out why the car gets as warm as it does just idling in the garage. I removed the engine-mounted thermostat and tested it in a pot of water. It seemed to start to open a little late (around 195 or so) so I ordered a new one.

I also pulled loose the oil lines that I had disconnected for the engine removal. I had kept these plugged up when the engine was out but wanted to make extra-sure that I didn't have a dead mouse or other blockage somewhere. Everything looked clear. I also removed the oil line which runs from the external thermostat housing to the oil tank. It had a slow weep at the thermostat housing, so I had ordered a new one along with the thermostat mentioned above. Note that this line came off much easier than I expected - I had soaked the fittings with PB Blaster for a few days. I was able to slightly tighten and then loosen the oil tank end with my line wrenches. I went ahead and cut the nut on the thermo housing end with a Dremel and then whacked it loose with a chisel placed in the cut groove.

While the lines were off the oil tank, I used a cheap borescope to look into the tank and through every oil line that I had loose. All looked clean and clear.

The new thermostat element (engine-mounted one, remember) and oil line arrived yesterday, so I installed them and refilled the tank with 20W50 VR1. Ran the car and checked things out with my IR gun.

After about 25 minutes, I was seeing about 210 at the oil tank and the external thermostat housing. The bottom of the crankcase was showing around 235, and this closely matched what my dash gauge indicated. At this point, the test loop Len had provided DID suddenly get hot. So I have return flow through the external thermostat, but at a little higher temperature than I would have expected.

The test loop is going back to Len and I'm going to hook up my front oil cooler one last time and check it again. Since I was stopping my test previously at about the same temperature that I did see flow up front last night, I want to double-check that I do not see the same through the cooler before spending the money for a new one.

As far as the car getting as hot as it does while idling, I think I'm at the point where I'm going to have to take it to my mechanic. When I get it back together with front cooler installed I will take it for a drive and see how it behaves driving vs. just sitting and idling. I am wondering if the car is very lean at idle..Is this something I can check without an AFR gauge? Does it make sense that it would run this hot due to a lean condition?

Thanks again.

I was thinking about your problem the other day and checked my front cooler after a fun ride and it was still cold. I really don't think mine opens up unless I'm on the track.
I'm just supporting my theory from a few threads ago that I feel it's a problem within the engine.

Anyone ever heard of an engine-mounted cooler plugging up? I've only read of failures due to leaks...

External thermostat
 

The external thermostat on my SC opens at about 190-200 degrees. Once open, the oil lines to the front warm up but not too fast. Once the lines are open, the front cooler (a large Setrab unit) keeps the temps around 200-210 degrees even in very hot weather. I also have a blow thru fan on the front cooler but seldom need to turn it on. I think you have a restriction somewhere in your engine that is keeping the oil from circulating as it should. Or, your engine may be running extremely lean at idle and at speed. Good luck with your search!

Have you checked the flow thru the radiator cooler? i.e. Remove it and fill the cooler with a solvent and blow compressed air thru it to be sure it is flowing properly.

Another thought on overheating. I would recommend pulling the alternator and looking
at the area of the cylinder fins for crud and corruption in there. There have been folks that have found rat's nests and other stuff clogging up the fins, or bunch of oil attracting
dust, dirt, leaves etc. Those conditions will definatley contribute a great deal to overheating as the airflow is greatly diminished. Just my $.02
Grant

Pic from another Pelican

[QUOTE=LUFTKUL;9437326]http://forums.pelicanparts.com/uploa...1484757143.JPG

My engine was just put back together and installed. I'm confident there's no crud under the shroud.

I'm debating pulling the engine oil cooler this weekend. Doesn't look like too bad a job on the 3.2 cars. ??

Just wondering if you ever successfully resolved the issue?

Hi again, I was asked to update this thread.

I ended up replacing both the engine-mounted and side thermostat elements. Even though the old ones seemed to test 'OK' using the pot of boiling water method, my engine temperature was reduced after replacing both. It also seemed to drop a little the more I drove the car. Since it had sat for several years previously, I wonder if there was some sludgy buildup in one or both of the oil coolers, or in a passage somewhere. I put a few miles on the car, changed the oil again, and found that I could drive it in mid 90's temps (late last summer) with the oil temperature never rising above 190 or so.

Thanks again for all the help.

Question Rbarton, did you ever end up removing the engine mounted oil cooler? Did you ever see an oil pressure change once things were figured out... you had mentioned around 1 Bar per 1,000 rpm in a previous post.

Lastly, what do you attribute the success to, changing the engine mounted thermostat as well as the other that you already had been messing with? Working on why my front (wheel well mounted) t-stat isn't opening either and have ordered new internals from Porsche.

Thanks for any input and glad you were able to figure it out.

I never did remove the oil cooler. My oil pressure didn't change; still at least 1 bar per 1krpm but not excessively high. I never did find out for sure what the cause of my initial high temp problems were, but they haven't reoccurred. I still wonder if I had some sludgy buildup in one or both of the oil coolers from the car sitting so long. The new thermostats did appear to help somewhat, although the old ones seemed to open OK in boiling water.

Good luck with your thermostat replacement. I found that I was able to get the housing caps off by soaking with PB Blaster once a day for a few consecutive days and then using a small pipe wrench as I recall.

Found the issue. The thermostat in the wheel well had failed. Boiled and still hadn't opened at 212 degrees F. Replaced with new internals and new sealing ring from Porsche. All good!