oil in coolant

[JonathanT]

('99 serp chimaera) I've got what looks like a little oil in my coolant - it's left a little tide mark inside the expansion tank. I've also got what seems to be a leak in my cooling system as air is getting in somehow, but it seems to be only a limited amount of air. The oil filler cap is totally clean of mayo as is what I can see of the inside of the rocker cover. Running temperatures seem to be ok, as is getting hot/cold air in the cabin.

The engine is consuming oil (a litre every 500miles), but I suspect a leaky sump and/or rocker gasket for that one.

Anyone got any pointers?

[WOO5IE]

Hi JonathonT,

All of your symptoms could be due to a Head gasket starting to go.

No gunge in the filler cap only means that water is not getting into the oil but it could be happening the other way round, It would explain the water and oil use

I am sure others on here will give other tip/suggestions

Head gaskets can be checked easily with a tool that measures gases in the coolant system which may be a good way to go.

Good Luck

Trev

[JonathanT]

Well I've decided to book it in for some diagnostics so we'll see what my local garage reports back...

[AlexanderV8]

I had a faulty head gasket on a car once where the only effect was the cooling system being pressurised. No mixing of fluids etc. and the only symptom was a fluctuating temperature reading, as the air in the coolant caused circulation problems.

I stumbled on the cause by accident when I loosened the expansion tank cap {long after it should have been cool) and it shot off, followed by a gushing geezer, nearly taking my head off and spraying me and the engine bay with filthy coolant!!

I think WOO5IE could well be right, your symptoms do sound like gasket failure.

Mick