Engine Underheating

My temp gauge has not been coming up to the first line. After a 25 min drive last night, the oil on the end of the dipstick was just warm. Maybe 80 or 90 degrees. Trombone oil cooler was cold.

Same thing this morning. Cold trombone (oil cooler for those of you with wandering ideas). Didn't check the dip stick, but the big oil line feeding the engine from the oil tank was barely warm. (80 or 90 degrees). On both occasions, I noticed that the oil filter is plenty hot MUCH hotter than the dip stick.

Perhaps this is nothing as the car has always warmed up slowly and it is quite chilly here lately. The trombone has been working (mine and the one in the car, in case you wonder), in the summer.

Sadly, it looks like I'll have to drive a longer, windy rural route home. For testing purposes, you know.

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'83 SC

Superman,

I have been experiencing the same "problem" here in K.C. I like the idea of my engine staying cool, but worry about things like the dreaded carbon chunks building up and possibly lodging under the valves, diminished gas mileage due to low combustion temperatures, spirited driving with 120 degree oil temperatures, diluted oil due to unburned fuel washing the cylinders etc...

Glad to hear about your trombone.. I think.




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John
73 911S

My oil temp doesn't ever reach the firt mark either. It does come real close under hot stalled traffic but other wise is at least one needle's width under mark.It used to almost reach the red till I changed the sensor and the new readings brought me great relief, maybe I shouldn't be???

Just wondering...

Jean-Paul with a 3.2

ok,

Here is my experience and I think your questions would be best answered if you indicated the outside temperature. I know KCMO can get quite chilly in the winter, I go there often and it gets cold! Lately It's been between 15 and 35 degrees farenheight where I live (New York City country suburbs) and to be honest with you, my oil temperature seldom reaches 150 degrees. I have no trombone cooler, just the regular old cooler and tank. I dont think we are all experiencing malfunctions with our temp sensors. Lets remember that these cars are air cooled and that when we drive them in temps below freezing, that will have a significant impact on the engine temperature. The only thing I like to keep in mind is to let the car warm up substantially before hard driving. I have forged racing pistons that are more prone to floating around the cylinders when cold.

Hope this helps

Bruno
73 911E coupe

[This message has been edited by Bruno Lavion (edited 12-07-2000).]

Just my uneducated guess, but it seems strange that the oil filter would be hot while the trombone (the cars) is "cold". Are the oil lines hot, warm, or cold? I don't think there was a regulator in trombone system that would prevent oil from flowing and therefore the lines would at least be warm, especially if the oil is hot enough to make the filter "hot". I have heard stories of cold oil clogging the pipes. This is propably not helpful but I though it might spur some feed back. I've never driven my car in less than 50 degree weather so I am unfamiliar with the snow climates.

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Paul
79SC Targa

Thanx for the replies. Our temps can get as high as 50 or even 60, but have been typically 25 to 45 degrees. I believe my gas mileage is not what it used to be.

Folks up here with 11-blade fans should perhaps switch with folks down south still using 6-bladers.

I just wonder if my engine-mounted oil cooler is even coming on. My thermostat o-ring leaks like mad.

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'83 SC

I am in the same status with my '73 T 2.4. I have an external oil cooler up where the trombone used to go and here in Atlanta my oil temp sits just around 150 I am using 20/50 Valvoline Racing and am considering a lower viscosity like 10 - 30 for winter driving. When I use my hand throttle to start in the morning that baby slams right into 2.5k+ rpm and you have to wonder what kind of shock is happening internally with pretty viscous oil trying to get around. I know this is violating the Porsche oath but has anyone ever tried one of the friction reduction lubricants like Slick 50, etc. or is this stuff prone to blocking small lubrication points.

BR

I guess that's one of the big advantages for synthetic oil. I'm using Mobil 1 15W50, and at 2 below, the car turned over and started like it had 5W30 in it. I know some people experience leaks in older cars, but my 79 doesn't leak any more (or any less) than it used to before the synthetic.

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Bill Krause
'79 911SC Euro

Hello Superman,

I don't think you need to worry at all - treat the car with sympathy when you first drive it cold (keep the revs below 3500) and simply drive as normal.

Air-cooled engines MUST run cooler when the cooling medium (air) is also cool. Its logical and its normal.

Just count your blessings that the joys of anti-freeze, silted/blocked radiators, perished hoses, worn-out water pumps, and so on are something we 911 owners never have to think about.

- roGER

Well, again, my system otherwise has seemed to operate properly. I suspect that the heat generated in not sufficient to invoke the trombone thermostat. I further suspect that my very gentle commute driving (50 mph posted speed limit, max, for twenty minutes) just does not get the tank oil hot enough. I expect my longer and more vigorous drive home tonight will produce a hot dipstick. I believe the engine parts achieve the proper temperatures. But my gas mileage still sucks, compared to summer driving.

Now, if I could only find a reliable method of warming my trombone....

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'83 SC

You might try swithing to a lower weight oil in the winter time. That would raise your temps, make those cold starts easier, and help a little with that mileage problem too.

-EJ

Gees...50mph, I'm sorry....

I've been variously told my gauge should read dead center as well as were it is, at or bellow the 1st mark. Am in San Francisco with 60 degree weather and reguarly drive 50+miles at 90/as well as city traffic and the gauge is pretty much always the same.

Any definitive answers to where it should be????
Thanks, Jean-Paul

Hey Superman,

I don't think your 20 minute drive is long enough to get the oil up to 'normal' in 25 degree F weather! And that is not cold enough to justify changing oil grades ... even if you could get some of that 0W-40 European oil, it would just mean you have got 12 qt. of cold 0W-40 oil circulating around after 20 minutes ... nothing wrong with 20W-50 in those temps of yours!

And, I'm sure you are just experiencing a bit of 'fixation on the oil temp gauge' syndrome, hoping nothing goes into the red because of that leaking thermostat O-ring! Nothing wrong with paying attention to the temp gauge, and I bet your extended test this evening will get it up to 180 F ... just like normal! Good luck!

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Warren Hall
1973 911S Targa

Aw thanx. I love you guys.

Warren knows that I recommend folks relax about their cars because I have victimized myself with anxiety more than most, and this is probably an example. Thankks, Warren, for the validation that 20/50 is good unless temps get a bit cooler. As long as the engine is getting hot enough, I don't really have concern about oil viscosity being too high. That's like worrying about being too good looking. I don't have either of those things to worry about.

I'll report my findings, probably tonight, for those interested.

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'83 SC

Warren-

I would think that 20w50 at 25 degrees would have the consistency of maple syrup! Even if the lower weight oil wouldn't help much for the temps, I am sure it wouldn't hurt. You would also get an increase in mileage wouldn't you? Or do I need to lay off the Swepco martinis?

-EJ

EJ,

It hasn't been that many years ago that 20W-20 Mogil oil was the 'standard' for winter use, in any climate but the Artic regions! And then a couple of decades later, 20W-40 grades came out! And, even later,
around 1970, Shell came out with a miraculous 10W-50! Must have had distribution problems or customer resistance to pricing, though ... didn't last long or at least Shell stopped pushing it in their ads!!!

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Warren Hall
1973 911S Targa

Big S - I don't know how you use your 911 but if it is used often in the winter you should at least run 10W40 if not something lower. The reason I say this is that the weather could take a turn for the worst while your car is out. This logic also applies if you don't have a heated garage. Right now it is between 10 and 25F here in the midwest. It takes my car a good half hour to warm up to thermostat-opening temps. I run 10W40 all year round. The lighter oil will also make life easier on your starter and battery in the winter. Every little bit helps. My daily ride (V8 S10) gets a 5W30 change every thanksgiving. I notice the change in morning start-up immediately. I don't like that it takes so long for the P-car to warm up in the winter, but unless I water cool it this won't change.

Took a freeway drive which finally got the tip of the dip stick hot, but the trombone stayed cold. This was followed by 10 or fifteen minutes of city / show country driving which cooled the dipstick. The gauge got closest to the first line on the freeway. I guess this (usually) 30 to 40 degree air just keeps it that cool.

Such is life.

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'83 SC

I experience problems with slow warming up during winter too. it's natural with an aircooled engine. However it prolongs the "cold start" and thereby puts more wear on the engine components than it would during summer. So in order to get the best protection I use 0W30 in my 3.2. I hope this will help the oil getting quickly around inside the engine when I make a cold start. I don't think this thin oil will help the engine to warm up sooner though. The oil just work better at winter temps than say a 20W-50. When I switched to using 0W-30 in my former car (economybox) I got a slight improvement in fuel consume. Less resistance in the engine I think... My 911 though has the same fuel economy as always...? I drove through summer with the 0W-30 oil without the gauge ever going past normal operating temp. The oil preassure stayed normal too. The car burns only very little oil and oil leaks are rare and tiny.

Unfortunately the only cure for long warming up times is parking the car in a heated garage....which I don't have.

The oil issue has been intersting and I will stick to 20-50 down here in Atlanta where it hardly gets below freezing during the day.

One big question I hope someone answers is the use of friction reducing additives. I am sure this has been brought up many times before. No doubt the greatest wear is at start up so do additives like Slick 50 or the other marvel low friction stuff work well in 911 engines?
I had this stuff in my 944 engine for years and noticed it ran cooler and the reports are in that it does indeed reduce friction at start up. Whats the concensus?
Thanks

BR
"73T"