hi guys, been looking at another car and only fault found was milky residue inside filler cap. oil on dipstick seems ok car drives fine, not appearing to be running hot, not pressurising the expansion bottle and no unwanted signs out the back. i,m really keen and it could be nothing but may be something. any advice and any test that could be done without pulling apart. its an audi rs4 so a big lump if it is nasty. thanks all
If the oil turns to a 'baileys' looking substance then the coolant is mixing with the oil. If it's only a small amount then you've caught it early. Pressure test the cooling system to see if there is and loss of pressure which indicates either a leak somewhere in the system.
The baileys residue inside the oil filler cap is condensation.It is caused by running the car on too many short journeys,not had a chance to warm up to a decent temperature.Leave it running for an hour or take it for a 15-20mile run it should clear itself.Once clear go back the next day and it should be fine.You would be worried if it was on the dipstick or inside of the expansion bottle.I see this everyday especially old folk who only go a mile or so down to the shops and back.
Remember how humid it down here at the moment it is too mate. If the engines been running for short distances and the heat of the oil isn't burning of the moisture trapped above it, it'll condense out to form the cappuccino slime you're seeing. It used to play havoc with the oil level window on my Ducati, getting in the way of a good reading, and that was air cooled so there was no question of it being a coolant leak.
thanks guys. sideways , i did have a 10-15 mile drive in it but still there when i came back but it has been damn cold. the owner who,s in the industry (sales) said he,ll do a test on the coolant to check for traces of oil or carbon i guess. can,t think what the name was. been wanting 1 for years so must ensure its the right car i pick. ,andrew, i wish i was earning too much lol
10 or 15 miles may not be enough mate. The cack in the filler has probably been building for a while. In the old days there used to be like a Brillo pad in there just to trap it. When I queried it with my 750ss I was told a good half hour or 30 miles just to burn of the existing moisture. That still won't get rid of the muck in the lid. That'll have to be washed out. Then it's a question of not letting it come back.
