Panzerknacker

I did my research and read up on the possible consequences but I wanted to tell me story and get feedback from members. So a shop overfilled the oil in my 55 AMG. I didnt really know there was a problem right away, the car was running sluggish but then the red "reduce oil" warning came on once. As soon as I saw the warning I drained the excess oil, which was between 1 and 1-1/2 quarts. I had driven maybe 200-300 miles with the excess oil in the car.

I have been looking for any leaks and havent seen any, and haven't seen any blue smoke from the exhaust or anything like that. Car's performance has improved and seems to be running ok. Other than getting compression and leak tested is there anything else I should look for or do to prevent and minimize damage? Im hoping no serious harm was done since the red warning only came on once and I drained it as soon as I was able to after that.

MRAMG1

Well fisrt thing first, any damage that MIGHT have occured already has

So how can you minimize it now

Anyway, I would bet that you will be fine. The worst thing that could happen is/was you had a little windage in the sump. AKA crank and rods throwing around the extra oil. Not a good thing, but shouldn't be terminal either.

My worse fear would have been if you were beating the crap out of it, aka 5K+ rpms, as this might cause issues with the bottom end. HIGHLY unlikely that it is, but could.

A quart and a half really shouldn't effect the front or rear main as well.

As far as the compression check, I wouldn't waste the time unless you are having issues.

Drive it, and enjoy it

mrobinso

Any serious damage that occurred would not rear its head in the short term, if I understand things correctly. Search the forum for the thread where I posted about how I overfilled my oil a bit because I failed to drain both plugs on the pan and subsequently filled up with just under 9 quartz. Same symptoms. No short term side effects in the next 8 months of driving after I drained the oil, but then I totaled my car and will never know now.

My guess is you'll probably be fine, but others should chime in here. I believe overfilling the oil can cause oil leaks (as you mentioned) so its good you checked, but worse, having it too full will cause the engine to hydrolock. There is a terrific amount of load incurred when you have multiple connecting rods swinging through 4 inches of oil. Since you didn't drive it too long (200-300 miles) you're probably okay.

I know how you feel though, its scary when you realize what has happened. I had no one but myself to blame when it happened to me though, are you going to take any action against the shop?

Panzerknacker

Ok, ok... Any damage that would happen already has lol I get it...

Well, other than not doing any further business with that shop and telling local friends that they botched my oil change there isnt a lot of action I can take without repair bills or proof. I drained the oil on my own so I got nothing in writing.

MRAMG1

Do you have any idea on just how much oil you would have to over fill it by to cause this

Think gallons, not quarts

PS: Sorry, I just couldn't help myslef.

mrobinso

Hence why I prefaced it with a generality, not specifically relating the referenced outcome with the OP's situation. I don't think it would take gallons (plural) of overage to do this. Overfilling by up to 3 quarts you may be okay, but gallons? Any more than a few quarts too much you need to consider blowing the engine as a valid possibility.

kent426

The most that will occur is it will increase windage which causes a drop in HP. You will also get some increase blow by through the valve covers in to the intake causing it to burn off the oil. It just makes a mess but no serious damage.

Panzerknacker

So other than draining the excess oil, how do I get the HP back. Car still doesnt feel like its running at its full potential. Maybe its just me.

Slater126

Exhibit A of why you should either go to the Mercedes dealer or reputable independent MB specialist or do it yourself.

Oil changes seem simple but I too have had my C32's oil overfilled and the red light come on. Never again will I allow an "regular" mechanic to touch my car!

Slater126

I can't see a slight oil overfill like you describe causing this. The oil stays in the crankcase and at most will cause more oil to slosh around, possibly creating issues with leaks and hydrolock in totally extreme circumstances (probably not even possible with a 1-1.5 quare overfill).

While these cars are highly reliable (snicker), it is just every so slightly possible that it's a completely unrelated problem. My car has had two things go wrong at once, believe me! I'd say have the ECU scanned and see if it's stored any trouble codes.

betrezra

weather changes... temp, air quality, DA.....etc will effect hp/tq like you are seeing...

I doubt the excess oil is the reason.

The only damage I've seen from excess oil in a 5.0 mustang... (that's my only data point).... was leaky seals due to excess pressure........... this was a on mustang...... no other damage to report.

I would drive it and enjoy.

Don Nguyen

I regularly see BMW guys adding ~1 qt over/extra to their engines. Mainly guys who are the ones who are tracking their cars, so that the oil level is higher and prevent oil starvation from hard cornering. I would say if you had an extra quart of oil in there, it shouldn't do any harm.

mikekuriger

adding a couple extra quarts will not hurt anything.