A relative has just realised that they've overfilled the oil by more than a litre above the max mark. I've suggested they get the excess oil drained off asap.

The handbook and oil cap give the usual warnings about possible damage, but does anyone know the actual damage that is likely ???

Car is a gently driven, low mileage 2.0 petrol Fabia.

Have a read of the thread below. The relevant bit says:

An overfull oil pan may lead to oil leakage through the pan gaskets and seals. Excess oil also can contribute to higher pressures and excessive vapors in the engine crankcase. If the oil level is extremely high, the rotating crankshaft may strike the oil and cause the engine to labor harder. This can reduce gas mileage and actually lead to premature engine wear.

http://www.csaa.com/global/articledetail/0,1398,1004010302%257C2024,00.html

If the crankshaft comes into physical contact with the oil it can act like an eggbeater and turn the oil into froth. The oil pump isn't designed to to deal with such a mixture and the engine may well suffer from inadequate lubrication. Additionally, oil may be forced past seals and gaskets.

Oil frothing caused by crank dipping in the oil. This fills the oil with air bubbles which then get fed to the bearings causing loss of hydrodynamic pressure and bearing failure, ultimately engine seizes.

Get some oil out of it asap, as you suggested.

HTH

i think you can damage the catalytic converter as well. have read it in the handbook some where

i think you can damage the catalytic converter as well. have read it in the handbook some where

Correct. If the engine is overfilled, 'oil may may be drawn into the combustion chamber and passed through the exhaust system to atmosphere. This can have a detrimental effect on combustion and on the operating life of the catalytic converter.'

And let's not even go near the clutch plates

So basically everything mechanical is potentially knackered if you leave it like that !?

Good job they've only just done it and I was there to say get it to the local non-Skoda garage to drain some off (don't want any warranty alarm bells ringing at the dealer) - hopefully tomorrow.

Happened because they thought the orange plastic bit on the dipstick was the full mark so it was low. It was actually at max and they added another litre rather than 'fill it to the line' That would have been about another 3 litres..........

It will only take a mechanic 5 minutes to drain it off on a ramp - well worth a few quid.