Mayonnaise on the oil Filler Cap!

[Tweedle]

New to porsche 911, have a 911t from 1969 just completed a 18months refri. Notice when checking the oil, the oil filler cap & neck has a light coating off oil mayonnaise (moisture in the oil). Car has travelled just 750miles rebuild.

Any ideas where it is coming from? (Have cleaned & powder coated the oil container).

Anybody had anything similar?

[jrbennett]

I'm sure it's from condensation. You need to go on longer trips and get the oil hot to burn off any moisture in the oil tank.

[Aurel]

The good news is, this can't be coolant water mixing with the oil, cause there ain't any water cooling .

[docrodg]

If you live in high humidity or take it out in cool we eather this can happen. Drive longer, it is a good excuse.

[Joe Bob]

Drive it like a rental......

[stlrj]

It usually comes from moisture inside your crankcase from cylinder blowby that mixes with your oil. It's possible your oil temperature is not getting hot enough to evaporate the moisture entering your crankcase.

[gamin]

I always take the long way wherever I'm going in either Porsche. No mayonnaise.

[Bill Jennings]

Tweedle,

You have the perfect excuse!

Honey i'm just going out to clear the mayonnaise out of the Porsche.

I'll be back as soon as it's gone!

Cheers
Bill

[Guardsred911]

Originally Posted by Aurel

The good news is, this can't be coolant water mixing with the oil, cause there ain't any water cooling .

Yes, this is the one time when the solution is to drive more, not stop and change the head gasket....

[911pcars]

It's called "sludge". Not visible elsewhere as well. Nasty stuff; can block oil passages and reduce heat transfer. Follow the advice given and bring engine to normal operating temp. before shutting down, or change oil more frequently.

Sherwood

[OsoMoore]

I drive a short commute (4 miles) to work and back.
I will get this stuff building up as well, so I have taken to doing hour-long drives with the wife after dinner.

[Tweedle]

Will do! Looking forward to a good drive anyway.

[Paulporsche]

If the above doesn't help, you might want to try another brand of oil.

[diverdan]

Like everyone said, each time you start that engine and don't get the engine and oil hot you ad moisture to the crankcase. The length of time it takes to get above boiling is exasperated by either a thermostat in great oil cooling system or a thermostat in the oil lines that doesn't open. There really is a reason that the 964s don't have an engine mounted oil cooler. By eliminating the engine mounted cooler, the thermostat in the oil lines can better do its job. When running my older 911s, I restrict the air intake in cool and cold weather, but just enough to make sure that a short 10 or 15 mile drive can get the temperatures up enough to prevent condensate. Be careful with this method, the engine you fry may be your own.

Diverdan

[manbridge 74]

I block my grille off (90%) as well when it is really cold.

[Jerome74911S]

How cold is "really cold"?

[Janna James]

That is so wrong on so many levels.

[manbridge 74]

Originally Posted by Jerome74911S

How cold is "really cold"?

Coldest start I've had was around 5 degrees (F).

@janna ...... Nothing wrong with a little blockage when I'm driving the 5 miles it takes to run around small town doing errands.

Too cold is almost as bad as too hot, just takes longer to see the results.

One can always quickly remove blockage. Also works that there is very little stop-n-go traffic here.

It also gets the aux t-stat open, keeping the oil in the front cooler going through the system.

[beech33pilot]

Since the water vapor rises to the highest point in the system, just remove the cap until you are cooled off.

[porsche930dude]

the pcv system should remove the vapor in theory. once its hot enough. I dont think the 911 pcv system is effective as other engines though. since most of the oil and vapor isnt actually in the engine.