OIL LOOKS LIKE MAYO

[kking183]

i checked the oil level on my vauxhall astra today and it was a bit low so i went to top it up and when i removed the cap the underside of the cap was covered in something looking like mayo and so was the top part where you fill with oil i know this can generally be a sign of a head gasket fault but there are no other signs no oil in the coolant engine isnt overheating no misfiring is there anything else what couldve caused this

 

[JohnD]

you have water in the oil.

Usual causes are:
radiator water from gasket leak or frost crack (you should notice this from checking the radiator water)

engine is not getting hot enough to boil the water out (typical of frequent short journeys or sitting at tickover with heater on, especially in cold weather). in this case just take it for a half-hour run to get the engine nice and hot., verify that your radiator water is getting properly hot and you have a thermostat fitted which is not stuck open (occasionally on old cars you get a faulty stat or someone takes it out to reduce summer overheating)

 

[joe-90]

John's in good form. I agree that it's probably the thermostat that isn't closing. Does your heater get really hot or just luke warm? Does your heater get hotter when idling then cools as you drive? That is a classic symptom of afaulty thermostat. A head gasket always (in my experience) causes overheating.

 

[stevie-h]

Could just be condensation due to the weather, short runs, lack of use etc. Try wiping it clean and checking again in a coupla days...

 

[Stivino]

I wouldn't panic, I'd be inclined to clean it up and keep an eye on it. I'd also keep an eye on the water level.