Judging by the oil level gauge, after a warm car idles for a few minutes, oil returns to the tank. Does anyone think that it would be a good idea to turn the car off before this happens when parking the car for a few days? My logic would be that one would be leaving oil in the engine and passages instead of the tank. Pros? Cons?
As the title says, probably not something worth losing sleep over. But it hit me as I parked at the airport this morning.

 

the sump is lower than the tank anyway, so the oil will run into the case

 

I always let the car idle for however long it takes for the tank to refill. There's anecdotal apocrypha that this helps avoid SAI issues.

 

I had to look up pedantic.

I usually let my 993 idle for a bit before I shut it off. Just because I'm not ready for it to be over.

 

Amen to that.

However,Ii do not baby my Pcars. if I have hot turbos, i let em cool down before shutting down. If not, i just turn em off. I have a slow, long winding route to my home so it does cool down naturally. After owning 11 air cooled and one water pumper, (current DD), I've never had a problem.

 

I would worry more about being parked at the airport

 

Here is my thinking:

The main feed from the tank goes directly into the primary circuit for the oil pump and then onto the small oil filter, which is quite a bit higher in the engine, and then to the mains and distribution. Not much oil gets past the oil pump when the engine is off, and what does has to climb up to the smaller oil filter. The oil from the tank does not drain into the case once the engine is still, otherwise the engine will totally fill up with oil from the tank if the car is shut off.

The scavenge side of the pump is responsible for returning surplus oil back to the tank. If the engine is stopped with additional oil in the sump, it will not do much. If the oil is high enough, it may flood and protect the bottoms of the barrels, but I doubt if it will get much higher or protect much more.

I suspect that the incidences of the "startup puff of smoke" will increase if the car is shut off without idling due to more oil being in the barrels, and possibly seeping past the piston rings. I cannot prove this with any hard numbers though.

Cheers,

Mike

 

Exactly my thought jago, I wouldn't leave my 993 at the airport, unless you were driving your DD and were dreaming about the 993. That I can understand.

 

He probably parks it in the hangar.

 

well, it makes its way through the oil pump gears...its not a flood or anythiing

 

I did say that if you read my comment - what oil gets past the gear set has to climb up the feed tube to the smaller engine mounted filter.

 

pedˇantic

Excessively concerned with minor details and rules or with displaying academic learning.

Just in case you were wondering. Like me.

Mike

 

On the subject of "pedantic questions of the day," a while ago I proposed a "Questions that don't deserve their own thread" thread. I still think it's a good idea. I would love to have a thread like this stickied. It would be a great all-purpose FYI thread. I would love to have a thread to source for random tidbits about my car!

 

I don't know if you guys are aware of this, but oil sticks to metal, so that even when you turn the engine off, the insides of the engine remain coated in oil. Furthermore, the film of oil on the wear surfaces of the engine, such as main and rod bearings and camshaft lobes, is unaffected by the level of oil in the sump versus the tank.

 

I think that's a great idea! I have a million of these silly thoughts....