Contaminated Oil

[douglas9401]

Child one recently passed his test and is currenly on the hunt for a cheap, small car.
We had a look at a Corsa 1.0 on a 52 plate today, had a drive and all seemed fine until I removed the oil filler cap. There was a small dirty white/yellow deposit on the underside of the cap so I thought water contamination in the oil.
My question (at last) is, is a deposit of this kind always a sure sign of impending doom or can it be just one of those things that happens to older cars?

[Mortartube]

It is usually a sign of water in then oil. Possibly a failing head gasket. My advice is to move on and look elsewhere. You may be buying a heap of expensive trouble that a little more searching will save you from.

[KJN]

Check the oil dipstick to confirm if the oil looks milky or frothy.
otherwise it could just be that you have some moisture build up in the crankcase from repeated short trips in the car. engine has to get hot to rid of moisture.

[EDDIE51]

Yes I agree with KJN , a car that is only used on short trips often has some moisture in the filler cap.

[Buenchico]

I wouldn't be worried about a deposit on the underside of the filler cap. I would be very worried if the surface of the oil looked like mayonnaise. (A 'pencil' torch is really useful when checking).

[TWR]

The way the weather has been a few cars will be showing the same Doug, when the car is running does it give out a lot of white smoke? " Condensation" & how long does this last & take the cold weather into consideration, what's the mileage? Check the Coolant tank for sludge. On the market at this time there is a product called "Steel Seal" Is is very well recommended to do the head job without the removal of the head & can save you a lot of money.

[douglas9401]

Many thanks for your replies.
There was no other indication of an issue, the car drove smoothly enough although the temperature guage remained stubbornly at rest.
On balance I think we'll keep looking
Thanks again.

[EDDIE51]

You say the temp guage remained at rest ? Well if the car is running cold that would explain the moisture. Could be a simple thermostat fault .

[Hopkirk]

Not unusual at all for a Vauxhall in winter.

Nothing to worry about.

[oldhenry]

This is called 'mayonaise' by those in the trade. It is a cold weather problem and condensation causes it. The car is probably used for short runs as a motorway thrash would eliminate it.
I would judge the sale by other criteria . Is it an overhead camshaft? These have been known to break if teh oil feeds are blocked - beware