Safe oil temp?

Diablo Dents · 07-30-2006, 05:26 PM

At what temperature (assuming the oil temp gage it correct) should I be concerned? I'm not racing just driving

Oh Haha · 07-30-2006, 05:34 PM

The red line is the point of no return. You have a Carrera, right?
The temp gauge can be a little funky to read in these cars if you don't have the numbers. Somewhere between 8 and 9 o'clock on the gauge has been deemed acceptable. Mine runs consistently right around 8o'clock even in hot, humid weather.
EDIT:

Oh yeah,the search button will yield more information on this subject.

Diablo Dents · 07-30-2006, 06:05 PM

Mine does have the numbers. What Number in degrees should I try to avoid

Jack Olsen · 07-30-2006, 06:32 PM

You should be between 190 snd 210 most of the time.

230 merits concern. 250 means stopping the car and letting it cool down.

Diablo Dents · 07-30-2006, 06:45 PM

That's what I was looking for. I saw a devise here that you can add to the oil filter the helps cool. Are you familiar with it ?

Jack Olsen · 07-30-2006, 07:17 PM

What are your temps like? It's a lot better to find out why the car's running hot than it is to throw band-aids at the problem.

Diablo Dents · 07-31-2006, 06:54 AM

I'm not sure if it's running hot. I took it out yesterday up a windy local mountain. The climb was about 2500 feet. Tight turns but not able to get speed over 25. Outside temp was mid to high 80's. I didn't baby it by any means. It was 2'nd gear for the most part and rpm 2500 to 3000 most of the time. I stopped to talk to a friend with the car idling for 5 to 10 minuets. I looked at the temp gage and it was at 240. I shut it off for 10 to 15 minuets and all was fine. Going back down 2'nd and 3'rd gear rpm were 1500 to 2500. Temp went down to 200. I'm guessing this was about normal for what I was doing. I'm assuming that outside temperatures and sitting still idling have a lot to do do with each other

Eric P · 07-31-2006, 07:02 AM

I think Bruce Anderson said, "240 is hot, 250 is TOO damn hot" or something like that.

Miguel Antonett · 07-31-2006, 07:12 AM

According to what you did yesterday, it seems OK.
Never ever keep a 911 idling unless extremely necessary - no friendly talks while the engine is running... OK?

230/240* is hot and 250* (@ 10:00 o'clock w/o #'s) TOO hot.

cnavarro · 07-31-2006, 08:53 AM

Most of the modern syn oils specified by manufacturers - BMW, Mercedes, and VW specs call for the oils to hold up to 150C sustained or higher. Search google for light duty diesel global specifications and you'll read more than you ever wanted to know about what goes into certifying a motor oil for a particular manufacturer. That said, I was running 230+ oil temps for over 4000 mi on Royal Purple and oil analysis showed that the TBN and Zn and P levels dropped only 15% and there was no viscosity loss in the oil. A good modern synthetic should hold up the anything in the 230-250F range, no problem there.

911pcars · 07-31-2006, 08:59 AM

I believe your car is equipped with an electric fan on the fender-mounted oil cooler, but it doesn't automatically energize until some red-needled temperature (if at all). Driving at low vehicle speeds, especially at altitude, doesn't create enough airflow into the fender.

Our host carries a temp. sensor that energizes at a more realistic (lower) oil temperature. Better yet, use that plus a manually-controlled relay circuit so you can switch the fan ON or OFF at will.

Sherwood

Wil Ferch · 07-31-2006, 09:12 AM

Sherwood... no.... the fan didn't arrive as a factory item until 87/88. The 85 has no fan and no top-of-oil-cooler "bung" for the temp probe.

Correct...the OEM 87+ fan came on at 244 degF. A substitute temp probe from a 964 or a BMW can set this lower...to something like 211 degF.

- Wil

911pcars · 07-31-2006, 09:22 AM

Hi Wil,
Thanks for the correction.

In that case, an aftermarket fan (e.g. Spal) strapped onto the cooler and a switching circuit is recommended plan B.

Sherwood

Jack Olsen · 07-31-2006, 09:23 AM

The oil's ability to withstand the temperature is only one of the issues brought on by the engine running hot. Older Porsche motors weren't built with those temps in mind.

Idling will heat the motor up because no air is moving over the cooler and the main blower isn't moving much air over the cylinders. A cool collar or other cooling device won't do much for you there. But there's an easy solution. Turn the car off.

Diablo Dents · 07-31-2006, 03:59 PM

This is so interesting. I guess I'll have to drive it more to see how it responds to different outside temperatures and types of roads.