Oil Level

[goldhillman]

My CX3 Sport Nav petrol had its first service last Friday at 5900 miles. Oil and filter changed. Checked the oil level today after a run and a 15 minute wait to find it over filled by about half an inch above the max mark. Is this a bad thing? Should I drain off the excess? Looked for the drain plug but was put off by the plastic sump guards. I have a pump to remove oil via the dip tube but the pump tube was too large in diameter. Should I take it back to the dealer or will it resolve through usage? A bit annoyed. I have found this to be a common problem following service on several different cars - hence the pump!

[1Monty]

Shouldn't be a problem but to be on the safe I would let the dealer know.

[goldhillman]

Thanks 1Monty. I'm a bit old school and was brought up to avoid over filling as it could lead to damage. Perhaps no longer true on modern engines?

[DaveG]

Someone may correct me but, overfilling a petrol engine with oil is not so much a problem as with a diesel engine,

[goldhillman]

I was hoping someone more mechanically minded than me might have the definitive answer. I just want to avoid damaging my engine.

[jtonline]

DaveG I have removed the accidental duplicate posts as requested.

goldhillman, all I know is that in the manual it says "CAUTION, Do not overfill the engine oil. This may cause engine damage."
There may be a bit of leeway so that a small amount over MAX will not do any harm. However if it was me, and as my dealer is only a 20 minute drive away, I would be taking it back to get them to drop the level to the MAX mark.

[goldhillman]

Thanks JT. My dealer is not so conveniently located but I am tempted to follow your advice. I have always tried to keep the level between half way and max.

[anchorman]

They warn against overfilling because you can end up with oil in parts of the crankcase and emission system that should normally allow it to breath. It could cause pressurisation or even severe damage if oil gets back into the upper cylinder where it cannot be compressed. It is usually caused if a DIYer adds an entire 5 litre tub into an engine that should take 3 litres for example. I doubt half an inch would cause a problem but it may if dilution is a problem which raises the oil level further. I would check it on level ground after an overnight stand and I would mention it to the garage as it is a clumsy mistake and it puts the onus on them if problems do occur.

To answer the question about whether it is worse in a diesel engine, well both the petrol and diesel are direct injection engines and both are capable of diluting (raising) the oil but the diesel is almost definitely more prone. It would mean it would need sorting out sooner if it is already part way to the “X”. It could destroy a severely overfilled engine just as easily as a petrol.

[goldhillman]

Thanks anchorman. I actually managed to use my pump via a smaller diameter tube down the dip tube and removed sufficient oil to take the level to just below the max mark so much happier now. I will check again in the morning after an overnight stand.