Severe overheating issue - running out of ideas

[roblav]

Agree with thermostat, oil cooler blockage, or mouse house first!

[vash]

dog. your IR thermometer is good?

seems like you checked everything. including the mouse nest everyone keeps bringing up.

you have confirmed your thermometer is good?

[bobolsn]

Dog,

Sounds like you have checked everything. A problem I have experienced in fuel delivery and radiators is a vapor lock. Are the return oil lines positioned with a low/high point where a vapor pocket can not easily be displaced/flushed?

Good luck

[gogo22]

I had exactly the same symptoms! Issue with my SC was actually the oil pressure security valve, which was "open" all the time (should only open > 6bar). So - no normal oil flow could be established. These motors are not air-cooled, they are oil cooled.

I think there is also a temp valve (not the one controlling the 2nd circuit), which could probably fail.

Good luck!

[Ronnie's.930]

Originally Posted by gogo22

I had exactly the same symptoms! Issue with my SC was actually the oil pressure security valve, which was "open" all the time (should only open > 6bar). So - no normal oil flow could be established. These motors are not air-cooled, they are oil cooled.
I think there is also a temp valve (not the one controlling the 2nd circuit), which could probably fail.

Good luck!

The highlighted statement above is false.

[quattrorunner]

Originally Posted by gogo22

I had exactly the same symptoms! Issue with my SC was actually the oil pressure security valve, which was "open" all the time (should only open > 6bar). So - no normal oil flow could be established. These motors are not air-cooled, they are oil cooled.

I think there is also a temp valve (not the one controlling the 2nd circuit), which could probably fail.

Good luck!

??????

[Bob Kontak]

Originally Posted by manbridge 74

Can you turn fan easily by hand with engine off?

Yep. +1


Check the video out 36 seconds in. Are you sure there is nothing on top of the oil cooler that you may not have seen by only removing the plates to the left and right of the center fan?

Has Everyone seen this 3.2 Teardown?

[Lapkritis]

Should be able to see the top of the oil cooler by removing #6 cyl plug wire.

[boyt911sc]

Originally Posted by Dogbreath

Thank you for all your excellent suggestions. I tried a few more things this afternoon.

Pulled the plugs...they look fine not overly dry and white and not overly black and oily.

Tested the temperature going into the oil cooler and coming out with a laser thermometer...great suggestion by the way. It appears that the temperature coming out is quite a bit cooler than going in.

I also took off a WUR that was on a turbo and put my non-working one back on just to see if that made any difference. It didn't within 5-6 minutes of running that car the oil temp was over 210.

To answer a few for the questions asked...

I have the 11 blade fan.
I have a tested and confirmed working thermostat.
I have confirm proper orientation of the sump plate.
I have checked the oil pump pickup and it looked fine.
The are no thermal reactors
CIS appears to be working fine.

I can only image that there may be some blockage somewhere in the engine. It gets so hot so quickly I can't imagine what else it could be.

Thanks again

How did you test and confirm that the auxiliary thermostat is opening at 186°F? Not the engine thermostat but the thermostat by the right rear fender well.

Tony

[Ronnie's.930]

Originally Posted by boyt911sc

How did you test and confirm that the auxiliary thermostat is opening at 186°F? Not the engine thermostat but the thermostat by the right rear fender well.

Tony

In the first post, the OP said his car did not have an external oil cooler (just the engine mounted one) . . .

[Reiver]

Is the oil cooler 'clean'...if someone has overfilled the oil it can leak down and saturate the filter then allow for lots of dirt to become embedded in the fins. Just a thought.
You can get a good look from below it it's on a rack...unless you have SSI's that is.

[boyt911sc]

Originally Posted by Ronnie's.930

In the first post, the OP said his car did not have an external oil cooler (just the engine mounted one) . . .

Ronnie,

Do you know that a '77S (911) has two (2) thermostats even with a trombone cooler? We are talking about thermostats and not auxiliary or external cooler!!!

Tony

[Chuck Moreland]

Confirm that the oil temp sending unit is the correct match the dash gauge. There are two different sending unit/gauge combos 65-76, and 77-89.

Mismatch the pair and you have incorrect readings.

You most surely have the 77 dash gauge. But your engine was replaced with a 74, and unless the sending unit was swapped to the later part - you are getting bogus readings.

The correct sending unit for a 77 is 911 606 112 00

[Ronnie's.930]

Originally Posted by boyt911sc

Ronnie,

Do you know that a '77S (911) has two (2) thermostats even with a trombone cooler? We are talking about thermostats and not auxiliary or external cooler!!!

Tony

Tony, in his first post, the OP says that the car has only the engine oil cooler (no front cooler), so you are saying that he is mistaken? Yes, I know that 911s have an auxiliary thermostat if they have an auxiliary oil cooler (even the trombone).

[Jdub]

What Chuck said. I have studied this post and have not heard you rate a 250 on your physical exterior temp checks. I only know this match requirement after changing both gauge and sensor in my '78 from useless bands to actual temps.

[tevake]

But if he is confirming the high temps with a hand held device that confirms the temps , then there is clearly a problem.
Good suggestion brought up so far, and you do seem to be going through this in a systematic through way. Will be a learning experience for us all when the culprit comes to light. Hang in there, and be careful not to do damage in the mean time.

Cheers Richard

[T77911S]

do you have enough oil in it? dumb question, but you never know. it does not need to be full, although low could make it run hot, not sure if it would get hot as fast as you say.
it just sounds like oil is not getting to the cooler or air is not going thru it for what eevr reason.

[unclebilly]

I agree with the above post on checking your sending unit and making sure it matches your gauge.

2 other things to consider:

1. Pull a few spark plugs. Are they white? If so, you are running too lean and need to tweak your mixture.

2. In my 911 chump car, I had similar problems until I noticed that the plate in the gauge with the numbers on it was loose and so what was really 210 was actually reading 235 or more. It took looking at he temp under hard cornering to notice the gauge moving, not he needle.

[kodioneill]

IR thermometers are tricky they have issues reading correct temps when pointed at shiny surfaces like metal oil lines the readings will not be accurate. I would use a thermocouple device to back up your readings.

[Joe Bob]

Where is the OP located?

I agree that the temps and AFR need to be verified. Willing to help if he is in So CA.