How much damage can overfilling an engine with oil cause ?
 

Recently my Toyota dealer somehow overfilled the sump with 1.25L of Castrol Edge 0W20, YEP you read correctly - 1.25 litres. I dunno how they managed that but it happened. Upon pickup of the car I started it & immediately could smell oil burning like if spilled on to a hot exhaust. I drove 42kms before parking it in my garage, let it sit for at least 10min & checked the dipstick - it was WAY over. I double checked @ 30min and got same. Took pics of dipstick & emailed to dealer. I then proceeded to dump the excess oil for fear of damage & got it level to full line.

Question is how much is too much oil & how long before serious permanent damage is done to the engine ? I drove freeway for about 30kms then a few simple 60kmh backroads for the remaining 12kms say, took it fairly gently as I was on holidays & little traffic. Car drove OK although I noticed it was a little less peppy & didn't blow smoke etc, no spilling was evident on anything so the smell came from engine.

I have everything documented via email with pictures I took of that extra oil overfill & dipstick etc. Car is fine now, power back to normal although I'm not sure if any damage could be done to the bearings after a gentle 42kms drive with possible aeration of the oil, low oil pressure & below normal oil protection & shear levels.

Would love to hear what you guys think. Thanks

Can be just as bad as low oil as it can whipped and frothed by the crank, therefore has air entrapped in it as it gets pumped through.

Air gaps are not good for the bearings. Premature wear etc.

I'd suggest coming up with a way of getting the extra out without making a mess... Or if your unable take it back and let the dealership do it.

I dumped the excess as soon as I got home so all OK after that. But what about the 42k's I initially drove with all that excess oil ?

I wouldn't worry about it too much. It's unlikely you were abusing it enough to really cause problems. Just glad to hear you took care of the issue quickly.

Yeah, I'm just fussy that way - I mean I don't trust dealers to get the oil level right so I check it as soon as I get home. A lesson for everyone - ALWAYS check the oil level after an oil change & preferably after a decent drive with oil up to temp.

I never let the dealer change my oil . They let all the trainees do that

thought usually dipstick should only be read at such time that car has not been driven, otherwise will usually show more. ( ie older cars at least)

the burning smell could of just been some spilt oil that was heated up on block

doesnt sound too serious but good that you're weary of what happened...

Happened to me as well. 1 litre over the full mark. I didn't check my oil for quite a while and then went "oh crap". They did it with my previous car also. I will now always check the oil and wheel nuts before leaving the dealer. I had wheel nuts not tightened after getting a new set of tyres at a tyre place once and won't trust anyone.

Yeah, this might be a good idea from now on with me at least when dealer does any servicing & that is to check the oil level on flat surface before starting & leaving there. It's pathetic really, you pay these people to service your car & they can't even fill the engine the correct measure of oil !

It is also good to check that the sump plug and oil filter are tightened correctly.
One of my friends lost his sump plug when driving and another lost the oil filter when driving.
The end results were not pretty.

Unbelievable !

Anyone else with their opinions ?