How can too much oil damage the engine?

[harkgar]

I put too much oil in the engine and a red warning light came on telling me to remove some oil. The 2006 CDi has one catalytic converter and no other filter.

Is this really necessary? I can see how insufficient oil can damage an engine but not the reverse.

[lkchris]

If the crankshaft whips the oil into a froth, you won't have proper oil film protection of various bearings.

[TMAllison]

Just empty some into a clean container and then check it again and slowly add some back (if needed) until its happy again.

[iolithblue]

Originally Posted by harkgar

I put too much oil in the engine and a red warning light came on telling me to remove some oil. The 2006 CDi has one catalytic converter and no other filter.

Is this really necessary? I can see how insufficient oil can damage an engine but not the reverse.

the manufacturer is interested for two reasons, hence the CEL.

too much oil increases the emissions, as the oil makes its way to the exhuast,(unlikely you care)

and WAY too much oil can cause real damage thru hydralic locks, or foaming as stated = dead engine (likely you care)

[Diesel Benz]

Originally Posted by iolithblue

the manufacturer is interested for two reasons, hence the CEL.

too much oil increases the emissions, as the oil makes its way to the exhuast,(unlikely you care)

and WAY too much oil can cause real damage thru hydralic locks, or foaming as stated = dead engine (likely you care)

Note that the oil gets to the exhaust through the engine, from the breather to the air intake, turbo (if the car has one), cylinder and then exhaust pipe.

A diesel may start running on the oil mist, making it run faster, pumping more oil through the breather... you can guess the rest.

[harkgar]

Originally Posted by lkchris

If the crankshaft whips the oil into a froth, you won't have proper oil film protection of various bearings.

If there is excess oil in the engine some will stay at the bottom end with gravity even when the oil near the top gets whipped into cream.

I had a 1986 Porsche 911 Targa and I put way too much oil into the engine when it was new, before I read the owner's manual to learn that the dipstick only reads accurately with the engine idling (dry sump). I had to take the car out at night to burn off the oil - quite a sight - the rear end of the car was like that of a rocket blasting off there was so much oily smoke blowing off.

Nothing happened to the engine or the catalytic converter. I wonder why.

[lkchris]

"Dry sump" means the oil is stored in a separate tank and not in an oil pan beneath the crankshaft. Surely you were supposed to add oil to the tank and not to the "engine." Seems like overfilling the tank would cause the oil to just overflow. Yes, there is a drip pan beneath the crankshaft, but it's very shallow and the oil system is designed to maintain the level there at a safe level. If you somehow got too much oil in the drip pan, you were just lucky there was no damage.

[451/443=EW]

Simply you will put too much pressure in the inside of the engine, You'll blow the seals and hydrolics inside. How much is a new diesal engine will be your next question. If you dont know how to remove it tow it you a local dealer and have them take it out. Dont drive it, you dont know what damge you may have done even on a short trip.

[240D 3.0T]

A red warning light came on telling you to remove some oil, obviously thats what you should do!

[Untertürkheim]

Originally Posted by 240D 3.0T

A red warning light came on telling you to remove some oil, obviously thats what you should do!

+1

[lkchris]

Originally Posted by 451/443=EW

Simply you will put too much pressure in the inside of the engine

If the oil is frothed, there will be no pressure.

[lkchris]

BTW, overfilling is one of the reasons Mercedes (and BMW) eliminated dipsticks. Seems too many dipsticks were looking at them.

[harkgar]

Originally Posted by lkchris

BTW, overfilling is one of the reasons Mercedes (and BMW) eliminated dipsticks. Seems too many dipsticks were looking at them.

On the contrary it is a more fail-safe method of testing. MB obviously agreed and brought back the dipstick from MY 2007. Even if the computer fails you can still check the oil level accurately.

The removal of the oil and transmission dipsticks were done for the same reason as the plastic cladding on top of all newer MB cars, that is to discourage the servicing by non-dealership garages.

[harkgar]

Originally Posted by lkchris

If the oil is frothed, there will be no pressure.

In one of the oil company advertisements in the 1980s promoting synthetic oils it claimed that even with a dry engine coated with the good stuff the engine refused to seize.

Does it mean that excess oil is not a problem with synthetic oils?

[240D 3.0T]

Dude, its a simple solution.

Drain, the, excess, oil.

Too much oil is ALWAYS bad. If it wasn't a problem, Mercedes wouldn't have felt the need to include a BIG RED WARNING LIGHT for it.

[TMAllison]

Originally Posted by harkgar

In one of the oil company advertisements in the 1980s promoting synthetic oils it claimed that even with a dry engine coated with the good stuff the engine refused to seize.

Does it mean that excess oil is not a problem with synthetic oils?

If you believe the advertisement it means that no oil (ie: a coating only) is OK. It didnt address overfilling.