911sc STILL over heating

Roger911sc · 10-24-2014, 02:17 PM

I'm hoping someone can help me. My car is an 82 911sc. In an attempt to cure the car running hot, I recently pulled the oil lines off and fixed a kink in the line. Used the heat and pressure from great post on this forum. I also replaced the trombone fender cooler with an Elephant Racing Carrera style, with the fan. Checked both oil thermostats. Inner was only opening up half way, so that was replaced. External thermostat was working correctly. Had my mechanic work on the timing and mixture.

The car runs great! Super smooth. However it still runs to what I consider hot! Driving around the city today in 86 degree weather. Lots of stop lights, the temp crawled to about 240. See picture. Seems with all the work on the car it should be way less that that. But I am stumped as to why. Any ideas?

Roger911sc · 10-24-2014, 02:33 PM

Oh, forgot to mention I also cleaned all the debris from the top of the engine.

wwest · wwest's Garage

SEnsor?

allaircooled · allaircooled's Garage

I seemed to remember a thread about calibrating the gauge with the temp sensor or something like that. Maybe do a search. What I am thinking is maybe the gauge is wrong or not accurate.

Roger911sc · 10-24-2014, 03:04 PM

Thanks! I'll check the sensor/gauge.

Typ616 · 10-24-2014, 03:10 PM

Mine ran hot for 15 years. What you show would be par for the course for me on a hot day in traffic jams. If you are moving and seeing that, that's a bit high however.

I had the oil cooler fan (added a carrera one like you with a fan) work with a thermostat that I could adjust lower from inside the car. I had it set so low it ran practically all the time and it was fine. Cooler than what you see..

Like you I tried a bunch of things, timing, tuneups, heetsheets (remember these?), an opening in the bumper instead of a turn signal, Carrera cooler, Fan, new lines....that car ran kinda hot for the 100K miles I owned it ! And it ran great.... I suppose watching the gauge calibration is a good idea...

Josh D · Josh D's Garage

Sending unit is probably bad. Have you verified temps with an IR thermometer?

hbueno · hbueno's Garage

Definitely try an IR thermometer to check if it agrees with the gauge.

My SC runs cooler now that I'm using Rotella T6 5W40 vs any 20W50.

Huo

mca · 10-24-2014, 05:17 PM

Do you have your heater hoses connected and blowing air across (through) your exhaust?

G450X · G450X's Garage

A Carrera style cooler with fan should work fine in your case. I believe the 28 row brass oil cooler is better in traffic/low speeds, and the later Carrera style is better at higher speeds, but with a properly working fan it should cool fine.

Have you checked the cooler for proper flow (gets warm) and that the fan switches on?

I don't think the temperature indicated on your gauge is too hot, I looked at my older gauge (with temps listed), and it is probably around 210 or so (if the calibration is the same).

From what I've read, we try to keep the temp under 230 degrees or so on air cooled 911 engines. I think the factory Carrera fan kicks on at 244 degrees, a bit too late. You could try to re-wire a manual "over-ride" switch and turn it on when you want. I think the "track guys" usually mount a large front oil cooler which works well, but may require a new bumper (or creative installation) to mount.

bamboo sc · 10-24-2014, 05:34 PM

I also just installed a Carrera oil cooler with fan. The cooler really needs some airflow to it.
Here is my answer. Plus the horns are not in front of it.
This is on an 82 sc it runs 30-40 degrees cooler now.

mca · 10-24-2014, 05:44 PM

This doesn't help when stuck in traffic, but I can vouch that a tail will drop temps at least 10 degrees when moving at moderate speeds. I put a duck on my 82 a couple of years ago. Big big difference.

mca · 10-24-2014, 05:45 PM

G450X ... On an 82, his pic is showing close to 240.

lrodri64 · 10-25-2014, 03:06 AM

Hi,
Do you still use catalytic converter ?
I had one completly blocked.
Try a test pipe.

Bear911 · Bear911's Garage

Despite what the literature says, the internal thermostat can go bad. The little heat-activated plunger inside the piston doesn't last forever. Unfortunately the entire CIS needs to come off to replace it.

Two small pointers for anyone researching this option:
1) the forum says to put the thermostat in oil and heat on a stove to check the function. This is nuts! Water is waaaay safer and cleaner and works just the same.
2) You don't have to buy a new internal thermostat if it is bad for $$$. Just get the external thermostat rebuild kit which includes the new tiny heat-activated plunger. The rest can be reused.

4495 · 4495's Garage

I'm not sure if I'm repeating the above but a Wheeler Dealers episode had Edd China curing a 914's overheating issue by replacing the spring in some device that helped get the engine up to operating temperature on start up. Not sure if you can tell but I'm not a Porsche Tech.

chrismorse · chrismorse's Garage

Quote:

Originally Posted by mca

This doesn't help when stuck in traffic, but I can vouch that a tail will drop temps at least 10 degrees when moving at moderate speeds. I put a duck on my 82 a couple of years ago. Big big difference.

Not to hijack the thread, but hey MCA, could you elaborate on the cooling aspect of the tail installation. I have been thinking that the sugar scoop tail must create more air pressure on the engine grill area - and help cooling???

chris

porsche930dude · porsche930dude's Garage

mine always ran hot like that. eventually I put in a numbered gauge with matched sender and then it was fine. upon closer inspection the sender was not correct for my car

The cap'n · 10-25-2014, 02:58 PM

I dealt with a couple of cars 10-15 years ago with similar overheating issues. After a lot of hair pulling and parts swapping, the answer came to us during an oil change on one of them. The sump drain plug was located directly under the oil pump pickup. Rotated the sump plate 180 degrees and the problem went away. You might want to take a look at that ...

Once you're back on the top of the engine, make sure the part number on the temp sender is correct for the instrument. This is more commonly a pressure gauge problem, but you never know.

The Cap'n

mca · 10-25-2014, 03:43 PM

The tails direct more air through the grill, to the fan, and across the top of the engine. I've heard that some folks will remove them in the winter in order to help get oil temps up.

Quote:

Quote de mca

This doesn't help when stuck in traffic, but I can vouch that a tail will drop temps at least 10 degrees when moving at moderate speeds. I put a duck on my 82 a couple of years ago. Big big difference.

Not to hijack the thread, but hey MCA, could you elaborate on the cooling aspect of the tail installation. I have been thinking that the sugar scoop tail must create more air pressure on the engine grill area - and help cooling???

chris