Ben Lovejoy

I have a 1981 SC with a 993 varioram engine.

When the engine is warm (ie. just returned from a drive) and idling, the oil level gauge indicates the correct level (ie. agrees with the dipstick). At all other times, it seems to show random values.

I know it's only valid when warm, but even when the temp gauge is in the middle when driving, it can read anything from zero to the actual level, with no apparent pattern that I can spot. It's only stationary and at idle that it seems correct.

Is this normal?

Ben

Dave Thomas

Completely normal.

Ben Lovejoy

Great, thanks for the reassurance.

Ben

Dave Thomas

Ben - sorry for the brief reply. Here's what's going on: with the dry sump design, the oil is constantly circulating through the engine sump, oil pump, hoses, tank and coolers. The oil tank is a kind of central holding cell. With the engine at speed much of the oil is in circulation and out of the tank, then it gathers there again at idle. The volume of the oil is also greater when it's up to temperature. That's why you only check the oil with the dipstick when it's hot and has been at idle for a couple of minutes. When you come to a stop you can watch the oil gauge come up as the pump refills the tank. This is also a good thing to do when shutting the engine off after a drive, as it empties the engine sump and reduces smoking at the next startup.

SeattlePorsche

Hmm, thanks Dave, I didn't know that. I always wondered why I get a little smoke at startup.

theiceman

Hi guys .. what a coincidence I just replaced mine on the weekend ( sender unit ) . Sorry if I am hijacking the thread but thought it was relevant.
Mine always showed about about 1/16th above the red no matter what the level in the tank and it was pretty all over the place when driving. .. well betwenn 1/16th and lower. On the weekend I replaced it and the one I received was different , it had a much shorter arm on the float , the one in my car ended in a 1 the replacement ended in a 2 ( p/ N ) . anyway the replacemnt works fantastic , I am about 1/6th below full and that is exactly what the gage shows. As I accelerate it lowers ( as oil is pumped out of the tank ) and if I idle it goes up . Needle doesn't even register till oil warms up. about 20 seconds of idling when warm and the needle is right up to where it should be.

I wonder if Porsche updated this part ? my original was date coded 01/77 ( i have a 78 ) so appears to be about right. So i wonder why the difference.?

Dave Thomas

Another thing you may notice, that is also perfectly normal: After driving a lot in cold weather, or after doing a lot of short trips (conditions under which the car will run richer), the oil may have some additional fuel in it, which will burn off the first time the engine gets good and hot. I get this every spring, during the first long, hard drive in hot weather. I'll come to a stop, and the engine will be smoking a bit; does it once and that's it. You can see the oil level drop a bit (as measured with the dipstick) after that too.