Engine Underheating

A recent issue of Pano had complete factory details on both synthetic and regular oils. I think it was the last issue. It shows the reccommended grades for a varieyt of temperatures extremes and those in between.

Finally I have asked this question on my home PCA board (potomac)and never recieved a good answer. What temperatures do the hashmarks on the gauge equate to ??????????
Also What kind of temperatures would you expect on a hot muggy day with the A/c cranked ????????????? Is it unusual for the temp to rise when operating the A?C???????
Any thoughts much appreciated.

Bob Sutton
1982 911SC Targa

Yes, oil temp increases with AC use.

Get this: The gauge is calibrated. At night, with the lights on or perhaps wiht a flashlight, if you peer at an angle from the passenger seat, under the edge of the gauge frame are TINY, TINY litle numbers. Good luck. I wrote them down. I'll look for them.

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'83 SC

Brose
I don't think you need additives to gain less friction or other advantages. Modern high quality oils have "built in" additives so that they work better. The 0W-30 Castrol oil that I use not only cleans the inside of the engine, but also reduces friction. You can also get 5W-40 or 5W-50 oils that work the same way.


RAS911
If you look at your temp gauge really close and a little from the right you will be able to spot some tiny temp numbers hidden behind the gauge outer ring. I'm not kidding. They really did put numbers in there although I can't see how you're able to use them while driving...?

Superman
You beat me on the oil temp numbers...

I didn't know they were there until recently. How would one be able to read them without crashing?? Sometimes Porsche surprise me...

Oh, I know, but the big thing is (and maybe this shoudl be posted in the thread about Porsche engineerign mistakes), the "operating" portion of the gauge is way too small. I have not located my numbers, but the "red" area on the gauge is already WAY too hot for yoru car. If the tiny numbers are correct (and I believe they are) your engine is overheating at about the second mark. The operating temperature range (180 to 250 I suppose) is only about 3/4 inches wide on the gauge.

Oh, I almost forgot. I have another concern. If I cannot seem to get my trombone thermostat to heat up, then when will I change the oil in those lines? I'd like to, at least occasionally, warm up my trombone (go ahead, tog, have at it). In this way, that oil gets into my engine. It's probably clean oil.

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'83 SC



[This message has been edited by Superman (edited 12-08-2000).]

on me carrera, first mark (fat white line) is 60 (140F.) next mark up (first thin line is 90 (194F.) next is 120 (248F) and finnally the red is 150 (302F).

Jean-Paul

I have heard about these little numbers before but never looked at night, I couldnt see any thing in daylight . I'll try tonight BEFORE I start my drive home!!!!! Thanks a lot. I have been looking at this board for a while and finally got the chance to support our host today with an order for some pads (metalmaster for street) and some shiny new lugs!

Two things, first, Superdude you don't live where it gets cold. How often does it get below freezing at night and stay that way thru the day, not often, and yea I know that they are predicting a cold front for our area, but it only lasts for a few days.

Second, is there not a thermostat in the line from the to the oil cooler.

Randy Jones
1971 911

Numbers? All I have ever seen is that little white horizontal line about half up the side of the gauge. I though this represented 210 degrees. Am I wrong?

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Paul
78SC Targa

Well I heard today, Randy, that temperatures may go below zero, Farenheit. And yes, there is a thermostat in the line that goes to the trombone cooler. I want that thermostat to open, at least once, between oil changes. If it does not, then September oil sitting in those lines gets into my engine for the first time in April.

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'83 SC

Superman
you were right ...... I will have to get a magnifying glass, but there they are plain as day, as long as you check at night !!! .
Who thought of that ? The bottom line is once you know what the lines represent you really dont need the temps to clutter up the gauge. However it would have been nice of the company to mention this in the manual!

Bear in mind, now that you know the temps, that anything above 250 is verboten, according to my understanding. So, if you let your needle go into the red, it's too late. This gauge belongs in the 'dumb Porsche engineering' thread.

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'83 SC

There isn't a 911 out there that would warm up proper here today. It is -30 degrees Celsius and -49 degrees with the windchill. It really really sucks!

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'76 911S

'80 924 M471

Boy am I glad to see this thread (and "oil temp?). All I ever see are complaints about overheating.
When I first picked up my '70T ~6yrs ago I thought the temp sender was kaput - replaced it and still noo temp reading - Oh, sorry, is reading, just not on the scale!
Never worried too much, but now is daily driver and moisture is building up (as well as the "snot" that RarlyL8 refers to in "oil temp" thread).
Manual says 176 is op temp, not to exceed 265F. Guage has big, bold numerics (gotta love those early cars) w/ 120 at the bottom. Temp barely gets above that even on the highway in the summer.
I'm worried about wear due to low temp.

Pre 3.6's have 2 oil coolers, 1 on the engine and 1 in the front fender. In cooler weather the engine mounted cooler is more than sufficient to keep oil temps down, hence the thermostat to front cooler never opens.

Rob,

You may want to check that temp sensor of yours by pulling it off engine, and with a test lead with two alligator clips, one to body of sensor, and other to a good bare ground connection ... and with power on to gauges, but engine not running, dunk the sensor in a small pan of boiling water. Those operating temps you cite ... ARE TOO COLD and sound like a stuck open engine thermostat!!! More likely is a bad sensor, though!

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Warren Hall
1973 911S Targa

I can try the sender test, but the factory-new sender registered exactly the same as the old one - also, the moisture build-up (the "tank-snot" that I referred to), although worse now in the cold weather, was pretty bad even on my summer drives between Seattle & Portland. Even then it only barely got above the first mark (120F). Even hot summer drives through the interior mountains never took it above the second mark (180F).
I was thinking the t-stat was stuck open, but that makes sense if it's a commuter-driving problem only.
Methinks I know why the factory went to the 6-blade fan (ooh, sounds like sacrelige).

Hey, I sure appreciate your input, all. This one is making me crazy!

Here is a bonehead solution, maybe. Just as long as you don't get boneheaded and forget what you have done. How about restricting the airflow to the engine or out of the engine? Semis and Volvos have used radiator shades for a long long time. Could a shade over the engine air intakes accomplish this? Would it be better to recirculate some of the air coming off the cylinder heads back through the system with a duct? Just don't forget it when summer returns! (Air restriction to the engine may or may not significantly affect the heater or manifold intake.) Come on Alaska and Lapland. Any experience with P cars regarding this?

Any chance you guys that can't seem to get up to operating temps are running with too rich of a mixture? That will keep the operating temps down too. I've been driving in near zero F temps and have had no problem getting the temps up to proper range.

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Bill Krause
'79 911SC Euro

Now you just might have something there. It is a bit of a stinker and I've never adjusted the mix. I'll try that fer sur.

It'll have to wait until I've got it back together though, the clutch fork pivot bolt (aka ball pin) broke yesterday - second time in 5 yrs - there's one for the dumb Porsche designs forum.