Overfilled oil

[jjad]

How much does it matter that I've overfilled with oil when changing it? Should I try and let a bit out (from sump plug), or leave it? I don't want to damage the engine! Thanks alot.

 

[Simon.AU]

How much is it overfull? If a lot it can get whisked into a froth at high speed, then the oil starts pumping air with consequent disastrous results. Also it can get splashed onto the cylinder walls and the car appears to be burning oil, or it pops the main bearing/crankshaft seals (or just leaks a lot) as the crankcase pressurises from too much oil and not enough space for vapour, or just forces the excess oil through the breather system....

 

[jjad]

Thanks for your reply, the oil level on the dipstick is just less than half the distance between the min and max above the max. The distance between the min and max is fairly small. Does anyone know what the difference in volume this equates to?

It's a 1108cc GTL.

 

[Simon.AU]

I would imagine the mix/max gap is the same on most of the Sierra iron block motors (R4 GTL & R12 (which I'm more familar with)) the gap in that case is about 1 litre (just under 1.5 pints) so I would imagine the overfill in this case is fairly minimal, the specified oil capacity in the sump being 3 litres with an additional .25 litre in the filter.