Kevinb

82 SC US trombone cooler
Oil - Mobil 1 5w-40 T&SUV
Timing 5 degrees
lambda system working frequency valve with dwell meter is 40-45%

I am having a problem with overheating the engine oil when the outside temperature is over 85 degrees F. A few times it has gotten to 250 degrees while idling and driving slowly. gets to 230 when on highway.

I have checked timing which is fine. I have checked fuel mixture which is lambda system indictates the frequency valve is adjusting for a slightly rich mixture. I have checked external thermostat and the trombone cooler is hot. I did have the supply line under the vehicle crushed 40%. I fixed the line and I am going to check if I am still overheating.

The question i have is 2 fold. I noticed a PO had changed the temp gauge to the numbered gauge. Do you have to also change the sender? I am wondering if they didnt change the sender and the gauge is reading incorrectly.

Another question, to verify the vehicle temp gauge, I have an IR thermometer and a thermocouple based electronic gauge. Where should I check the oil temperature on the engine to verify the vehicles temp gauge is working correctly?

Kevin B
82SC

DGaunt

You really need to upgrade toa Carrera cooler with fan and over ride switch. That will solve all your problems. What you describe is typical of trombone cars esp. with A/C.

pjc

Probably of not much help but...it may help to run the engine a bit harder if the oil is getting hot - idling or cruising around in top gear just doesn't get the cooling system working hard enough. I have a Sporto and the factory advice is if the oil temperature is looking too high drop to a lower gear and run the engine harder. These cars were designed for high spped autobahn driving and not slow speed work in high temperatures.

PJC

Noel

Good question on where to check the temperature. How about at the dipstick? I just looked in the Bentley service manual and they don't mention a location. At least it will get you close. Another way to tell of the temperature sensor was changed when the "Upgraded" temp gauge was installed is to simply examine it. The stock sensor sticks very far into the case, where as the old style guage sensor is much shorter.
Also, verify that the thermostat to the front loop is working properly by feeling the pipes in front after a drive. They should be hot. If not, then the front thermostat in the right rear wheel well is not functioning.
Next, verify that the on engine cooler is not clogged with debris. If not, then check the on engine cooler thermostat. When these fail, I'm not sure if they usually fail in the open position or closed position.

Good luck and let us know what you find out.

Noel

Larry Harris

The Carrera type cooler is the best way to lower the high temps you are experiencing.

Kevinb

The trombone cooler does get very hot. Almost untouchable.

How do you verify if the engine cooler is clogged with debris? I did pull out the fan and alternator slightly to verify if there was any cloth or items clogging the airpath and it was completely free. I didnt pull it out all the way to look all the way back toward the back of the engine.

Today is another hot day and I may go for another drive to see if it gets to 240 degrees F and check the dipstick. I want to see if my repairing the crushed supply line helped in any manner.

Kevin B

Steve Weiner-Rennsport Systems

Kevin:

I'd suggest that you pull the fan assembly and have a good look at the top of the whole engine. Thats the only way to confirm that the engine-mounted cooler is not obstructed and there are no serious oil leaks. I might also remove the engine thermostat and check it in hot water to ensure that it opens all the way.

Beyond those two measures, I'd agree with the others that the trombone cooler is notoriously bad in any kind of traffic and combined with hot weather, cannot maintain proper oil temps. A Carrera cooler & fan is strongly recommended.

Kevinb

Thanks, I will pull the fan and get a better look. I did partially pull it out but i was only able to see back about 1/2 way.

Can you remove the thermostat without lowering the engine? I changed the clutch last fall and replaced the o-ring on the thermostat. Could I have put it back in the wrong way? I checked if I could place it in the wrong way and it didnt appear to be a wrong way.

Kevin B

theiceman

Kevin to answer your sender question about temp . I just diod this mod and if anything I wondered if my sender was sending to low a temp to the guage but I am convinced now it is right. But the original sender IS different from the one in the numbered gage kit. The original when you remove it is about 1 inch or even 1 1/4 inches long going into the oil . The newer one is not even half an inch . You have to take it out but at least you will know. If you want I can send you a pic of the original . I still have mine.

john d 81SC

Kevin,

FWIW I've been fighting the high oil temp issue since I've been tracking my SC, and what I have learned/spent along the way:
1. checking oil temp off dipstick - I'm told oil has been through cooler at this point, so not an accurate temp reading
2. I've removed the right front marker light and replaced it with the "Cool Scoop" , which directs air onto cooler
3. Replaced standard oil lines w/ finned Elephant Racing lines (sold my original lines to help offset the cost)
4. Using Mobil 1 15-50 (in Mid Atlantic area - near Phila); supposedly runs a little cooler and not as susceptible to higher temp breakdowns
5. replaced the trombone w/ the Euro 28 tube brass cooler ( a gift from a good friend that totalled his SC at the Glen
6. the PO had switched to the numbered temp gauge which requires a pre-1977 oil temp sender gauge. This sender is recognized by the flat circular disc extending from a "shaft"; the other sender has a flange which extends out and then takes an almot 90 degree bend (I guess describing the end as 'L" shaped would have been easier *G*)

The net results of all this - driving back from the Glen yesterday afternoon at illegal speeds in 85+ degree heat, temps never went above 210. Same around town. On the track, however, problem still not solved, so typically I come off the track a couple minutes before the session ends (before my temps reach 240). As long as you aren't planning to take your car on the track, sounds like the previous posts re: the Carrera cooler should solve your problem.

theiceman

John

FYi I just got my numbered temp gage kit and the sender does in fact have an "l" maybe it is a newer design.

john d 81SC

Iceman,

If you bought the gauge as a kit, especially from another well-known Porsche 'bird' site, and click on the illustration for the gauge and sender kit, they show the sender you have. I called that site for clarification because on the same page they also have the 1974-1976 sender (part # 901 641 632 00 plus the site's addl "M100") listed by itself, with the picture I described. The person I spoke to told me that sender is the correct one. Strange, huh?

theiceman

Well I don't know what to say , that is pretty strange .. I got the one in the combo pic and it seams to work well. When crusing arounf town I sit a about 190 and that is about where it should be I guess. Just wish it had been in celcius to go along with the KPH

oh well.