Mayo on oil cap

[Sy]

Hi All,

I'm sure it's nothing, but I noticed a while back that I had a bit of mayo build up inside the oil cap and wondered if it was serious?

I have had the car checked out by an OPC in Reading and serviced by an Indy back in November and everything came back 100% ok and I know the oil filler cap did not have anything on it then. However I did not use the car much over Christmas and if I did it was only for short trips. I noticed that some mayo had built up on the oil filler cap but I read on here somewhere that this can sometimes happen in cold weather when the car is not used much.

I had another look the other day when I topped up the oil and noticed the mayo had dryed out but it does look rather disgusting and wondered if I have a more serious problem I need to address?

Am I worrying about a common winter problem or should I be getting the car checked out again by a professional?

Any advise appreciated.

 

[Chief]

Sy
What oil are you using Helmans 0-40? or full fat?

Put it down to winter blues, lots of cold damp weather, short runs. I wouldn't worry.

 

[GT4]

"They all do it, Sir".

This time that's actually true.

Search for "mayo" on the forum.

All the 911s get it - not just watercooled.

You will get a million threads, you will also see it correlates with cold (winter) weather and short journeys.

The water and oil vapour from the engine condenses as an emulsion in the nicely cold and distant outlying horizontal filler pipe.

Having said that, this mayo can still be caused by a headgasket failure.

Firstly check the dipstick for water/emulsion cotaminatiom in the sump and also check for cross-contamination of the coolant in the header tank.

Make sure there is no water loss and the coolant is nice and clear - if the coolant has oil in it then you have a headgasket failure.

If no water/emulsion in sump and no oil in coolant, then just cold weather/short run "mayo".

Wipe off and drive faster and longer!

 

[Sy]

Sy
What oil are you using Helmans 0-40? or full fat?

Put it down to winter blues, lots of cold damp weather, short runs. I wouldn't worry.

I think the Indy puts in 5-40w in 996's. I topped up with a litre of synthetic magnatex gtx (couldn't find any mobil 1). But the problem happened before that. Like you say, I guess it's just temporary, scary though when you see it!

 

[GT4]

I think Chief was pulling your leg about the grade of (egg and vegetable) oil you use, it should happen to any normal oil as it is just the hot oil vapours combining with hot (combustion) water vapour and condensing in the curiously outlying tube of the 911.

In fact, technically, all things being equal, 0w40 and 5w40 or any Xw40 will have the same high temperature characteristics as each other anyway, as that is what the second grade scale measures (the first number being cold start characteristics).

 

[Sy]

"They all do it, Sir".

This time that's actually true.

Search for "mayo" on the forum.

All the 911s get it - not just watercooled.

You will get a million threads, you will also see it correlates with cold (winter) weather and short journeys.

The water and oil vapour from the engine condenses as an emulsion in the nicely cold and distant outlying horizontal filler pipe.

Having said that, this mayo can still be caused by a headgasket failure.

Firstly check the dipstick for water/emulsion cotaminatiom in the sump and also check for cross-contamination of the coolant in the header tank.

Make sure there is no water loss and the coolant is nice and clear - if the coolant has oil in it then you have a headgasket failure.

If no water/emulsion in sump and no oil in coolant, then just cold weather/short run "mayo".

Wipe off and drive faster and longer!

Legend! Thanks GT. I thought I had seen posts about this but I had never seen the mayo in any of my cars before now and thought it was not a good sign! Thanks for the reassurance. I will check the coolant but I have a feeling it was just the cold weather of Xmas.

 

[colt_phil]

Hi All,

Anyone any idea if this is common on Caymans?

I have a 2008 2.7 with 11k on the clock. Only bought it at xmas and I have noticed a small build up of moisture and mayo under the oil cap. Again it has been doing a lot of short journeys. Is the cold weather the cause or should I be expecting the worst.

Thanks

 

[colt_phil]

Hi All,

Anyone any idea if this is common on Caymans?

I have a 2008 2.7 with 11k on the clock. Only bought it at xmas and I have noticed a small build up of moisture and mayo under the oil cap. Again it has been doing a lot of short journeys. Is the cold weather the cause or should I be expecting the worst.

Thanks

 

[GT4]

Well, Caymans and Boxsters also have remote oil filler necks. Most cars have the oil access directly into the top of the engine (assuming vertical, not boxer), generally into the rocker cover.

The same rules apply in terms of ruling out head gasket failure (ie oil sump or coolant header cross-contamination).

If you can't find any head gasket failure the Mayo is almost certainly simply cold weather/short journey condensation.