Safest Operating Temperature... ?
 

I've got a concern about the temps I'm reaching in my 911 2.7CIS. In heavy traffic, in very mild weather 66Deg F (19deg C) the car's oil temp soars upto 212 deg F!! (100 deg C). Is this too high for a 2.7?? I've always thought so.

This is alarming to me, as the car normally never gets over 185 deg F (85 deg C). The car has had many of the preventative mods done to it: New timeserts with 11-blade fan etc etc, and has the trombone cooler (which is marked for Upgrade), but I'm terrified that even though the weather is getting cooler, the car's running hotter and hotter. I have replaced the external cooler thermostats and am running the car on 20W-50 Oil, and am now starting to panic. It's due for a tune, but can poor ignition timing (the car runs great!) account for such temps? Could it be running too lean? How do I adjust the mixture for this car? I want to make it richer if it's a contributing factor.

CIS gurus, please help!

Inaccurate ignition timing can cause your engine to run hotter and I would guess that anything that would make your engine work harder, would. How about the thermostat for the oil? Has any work been done to your car recently that could've kinked an oil line? My 77 with the original 5 blade fan and original oil cooler doesn't run that hot on a 90 degree day in bumper-to-bumper traffic.

Hi Adam,

Could be running to lean. DANGER TIME.

Does the temp rise quickly under load?

212 f is high for a cool 66 f day.

Have you tested the internal thermostat? It may not be opening completely.

Get the oil warm then put your hand on the internal oil cooler. It should be really hot, not just warm. Careful not to burn yourself.

My 2.7 cis used to run hot, 110 c to 130 c. I tried every thing, updated oil cooler, timing, mixture, etc... nothing helped.
One day I noticed that my oil tank had a thick oil/dust layer stuck to it, I cleaned it up and never ran over 110c on heavy traffic and 40c weather temperature.

I have the same problem. I drove my 911 for a while today. Tempature was up around 70 and engine temp. was 210. Even worse there was smoke coming off the heat exchangers(?).Can this cause a fire?

If you get enough oil on your exchangers (i.e. pretty bad leak over the exchangers), and they get hot enough (i.e. track day), yup.

Is this problem usually due to the valve cover gaskets?

It can also be the oil return tube o-rings or items on the top of the engine: oil pressure switch, engine mounted thermostat o-ring, breather cover gasket or breather hose. Jim

I'm going to book it in for a valve adjustment next week, so I'll get the timing and mixture checked too. I'll try to track down these temperature gremlins, even if it means changing the engine thermostat also.

MMBRAZIL, that's a very interesting point. I'll be sure to check under the guard tonight.

Chuck, it's a long story, but I had to go downtown for a meeting and that's where it got to 212 before I had a chance to park it. Later that night (9pm) when I left, the car never got over 180-185, mainly because I kept moving. I checked the oil lines under the car (close to the external thermostat) and nearly seared my fingertips off. So, oil is moving, it's just not getting cooled properly. :(

is that really that hot? my car gets to 220 driving around town.. seems normal. 180 - 220 when warmed up