Breather hose Mayonaise

[nick3814]

Checked the oil today whilst she was running at temperature and noticed a build up of that horrible gunk/mayonaise in the rubber pipe that leads from the top of the oil filler pipe and goes around the rear of the engine into the air cleaner (a breather hose I presumme), now I would normally associate this with oil and water mixing ( I had a problem with my 944 once when a seal went on the oil/water intercooler causing the two to mix) now the 911 is air cooled where has the water come from? Is it just moisture that has built up whilst the car has been idle over the winter?

Any ideas??

 

[Guest]

The usual reason given for this Nick is that the hose has perished due to age etc and is letting in colder air than is in the pipe causing condensation, which then mixes with the oil and gives a very small amount of emulsified oil. Several people have been concerned that their head gaskets have failed when they see this only to feel silly when it is explained that there is no water in the engine!!!! The only counter to the colder air getting into the pipe is that the pipe comes from your crankcase breather and should probably be a vacuum, somebody more mechanically adept than me will confrim/deny this.
Anyway check your pipe for cracks/perishing and then replace, it's a very easy job taking 15 mins or so.
Good luck
Regards
Ian

 

[engleflick]

Hi Nick,

I have had exactly the same with my car, I haven't used it since Christmas until I needed to the other day. On checking the Oil I have noticed the same 'mayo' in the pipe at the top. So it could also be to do with lack of use of the winter months.

 

[bones]

If it's the same pipe ththat I'm thinking (the one from the crankcase breather to the oil tank then the reason for the build up of emulsions is that the crankcase vents not only oil vapours but water vapours too when the engine is not at optimium temperature, also the route this pipe takes makes it possible for water to condense in there when the engine is cooling or heating up, if you could maintain the intense heat of the oil in the engine and tank when you run the engine as it should be (avoiding short runs that is) then there wouldn't be a problem , this pipe will always be sublect to 'the mayo effect', just periodically clean it if you can get round the back there (tricky). It's not a major problem unless it's completely gunged up, more serious is 'mayo' in the oil tank something I've never had [8D] , this indicates too many short journeys and low engine temperatures, change the oil more often if you can't avoid this problem.

 

[AirCooledExcellence]

It's completely normal, clean up the mayo as best as you can and take the car out for a good thrashing!!

Cheers,

Tim.

 

[bruceb]

The mayo is not a problem, its generally caused by too many short runs when the engine, and particularly the oil do not get warm enough. Clean it up and as s Tim said give the car a good thrashing, its what they were designed to do and run much better for it

 

[nick3814]

Sounds good to me, cheers lads.