My 74 911 is running hot

[Kurts74911]

I have owned my 1974 911 since 1985. No oil cooler installed that I know of. I Rebuilt it sometime around 1987 and used it for a primary car until 1993. Lived in Orange County, CA until 1993.

I do not have a temperature reading, just a guage that goes from cold to hot (hot is a little bar all the way on the right). I have been in upstate NY for the last ten years and recently moved to the western edge of the San Fernando Valley.

I have noticed that when it is over 90+ deg outside that if I drive on the freeway or in the Santa Monica mountains that the temperature needle will go at least 3/4 of the way to the right. I can't say I remember that occuring in NY and not even when I returned back to CA, but I never really drove the car more than 30 minutes at a time. It has been too long to remember what it read before I left as well.

Today when driving back from the Ventura Porsche show at about 1pm the needle what about 4/5 over to the right (about 1/4 inch from red). Going out it was greater than 1/2 but it was fairly cool at 10am.

I did recently have a timing chain replaced and a major tune.

My question is.......is this normal?? Is it because I live in the heat now? Is there anything to be concerned about?? I wish I could remember what it used to read.

Any help would be appreciated,

Kurt

[IROC]

Before you get real concerned, find out exactly what temperatures the engine is running at. It is normal (and expected) for the engine to run hotter as the ambient temperature increases.

Your car is right in the gray area as to whether or not a cooler is required. I would investigate the actual temps and make a decision at that point.

Mike

[Kurts74911]

Mike,
I appreciate your reply. I was kind of wondering because I now live in a hot area (it easily gets to 100 around here in the early afternoons during the summer), if it is just something that I haven't noticed before.

Honestly I didn't recognize it until I picked it up after servicing, BUT it was over 95degF outside.

My question.......
How can I actually measure the temperature. Is there some way that I can take a voltage measurement. Also, I was wondering how accurate the guage really is?

What bothered me is how far over the needle was, even though RED is at the very very end.

Thanks again for your reply,

Kurt

[Grady Clay]

Kurt,

The best way to measure the temperature is to get an electronic thermometer with a flex sensor that will fit in the oil tank when the oil cap is off. There are lots of inexpensive ones available. You can easily check its calibration with boiling water and an ice bath.
Make yourself a clear decal over the temperature gauge and make calibration marks from your measurements.

You have an oil cooler on the engine in the fan airstream. Most would agree that a 2.7 would greatly benefit from a front oil cooler. You can find a used one from any SC or Carrera. Some 2.7s came with them. There is a lot on this Forum. Do some searching.

Additionally you can change the engine fan configuration.
Fan drive ratio:
Engine Fan Drive Ratio
The 1.8:1 fan ratio is a good first step and is very effective for less money. It also improves A/C function.

For DE there isthe "Rubbermaid Solution."
”Water vapor cooled 911 - the Rubbermaid Solution


Best,
Grady

[Jdub]

I just installed Pelican's numeric gauge and associated sender. Highly, highly recommended: no more guessing!

You can use an IR gun on the oil tank, but as mentioned above ideally you put a thermo into the oil tank and get a sense of how hot you are running.

John

[Joe Bob]

I have a hand held Pyrometer....use it all the time. I have id'd at least three screwy gauges in the 5 years I have owned it. No tool box should be without.

Summit Racing has them.

[Paulporsche]

Try looking around the extreme outer edge of the face of the gauge at an angle. One some of the gauges, there will be a temp value in small type. I don't know if it is on yours, but it is worth a try.

[MichiganMat]

what weight oil do you run?

[dd74]

Odd...my '74 has a numerical temperature gauge. And I thought all 911 engines have an engine oil cooler - not necessarily an external oil cooler.

My old 2.7 once reached well over 250 degrees while stuck in rush hour L.A. traffic. It actually ran fine, though constantly operating the engine at the temperature is ill-advised. I definitely would not drive the engine agressively at anything above 250.

Check under the car's right rocker panel. If you see piping going along there to the front right wheel well, and then inside the wheel well, see a small radiator, you have an external oil cooler. But like others said, standard '74s did not come with such a setup. I think they were a factory option.