Question about overfull oil - PeachParts Mercedes-Benz Forum

imagesinthewind · #1 04-16-2006, 10:36 PM

So, I've been driving my sweet (78 300SD) for just two weeks and have noticed a pretty interesting oil leak under the car on the driveway.
The hood latch wouldn't open the hood until today (more patience, more trying) and I got to check the oil.
Now logic and knowing other cars says the dipstick notches show both min and max for oil, right? Well, I pulled mine with a stone COLD engine and found the oil to be almost 3/4 inch ABOVE the top (max) notch.
I'm thinking this is the reason for the leak? Could the extra pressure of too much oil cause the car to leak while the engine is running?
Should I take the car to my guy and have the extra drained out? The oil has about 500 miles on it so i'm thinking a change is unnecessary.
So, any advice, comments?

#2 04-16-2006, 10:44 PM

Dumb question: Are you checking the oil level after removing the dipstick once, wiping it off, then checking the level? Mine always reads high when I first remove the dipstick.

imagesinthewind · #3 04-16-2006, 10:48 PM

Checked several times, wiped between.
VERY high level.

#4 04-16-2006, 10:51 PM

If it's really overfilled you should have the extra drained/pumped out. There should be no reason to change the oil/filter, just remove the extra. I like to keep mine about half way between the two marks.

Palangi · #5 04-16-2006, 10:56 PM

On some engines the oil likes to climb up the dipstick tube when it is cold. Warm the engine up and check it 5 minutes after shutdown. That should give you a more accurate level.

#6 04-16-2006, 11:04 PM

Quote:

Originally Posted by Palangi

On some engines the oil likes to climb up the dipstick tube when it is cold. Warm the engine up and check it 5 minutes after shutdown. That should give you a more accurate level.

I wouldn't recommend that on a 617, the oil may not all drain back in 5 minutes. That's probably how it ended up overfilled in the first place. I agree the oil will "climb" the dipstick the first time you check it cold. If you wipe the dipstick and recheck, you should get an accurate reading.

BTW, make sure you are on level ground when you check it.

vstech · #7 04-16-2006, 11:04 PM

check the saftey sticky above on the runaway diesel story... scary!

1985 300SD Sady · #8 04-16-2006, 11:05 PM

Quote:

Originally Posted by Palangi

On some engines the oil likes to climb up the dipstick tube when it is cold. Warm the engine up and check it 5 minutes after shutdown. That should give you a more accurate level.

AHH GREED.. You need to have the engine up to normal operating temperature but not running when checking the oil level. It is also manditory that your car be on level ground for your reading to be accurate.

Palangi · #9 04-16-2006, 11:11 PM

Yeppers, my old 240D would always read about an inch high when it was cold. My Isuzu diesel however, sometimes shows no oil at all on the dipstick when cold.

That always scares the hell out of me.

imagesinthewind · #10 04-16-2006, 11:31 PM

warm or cold?
Ya'll are confusing me!

#11 04-16-2006, 11:44 PM

Quote:

Originally Posted by imagesinthewind

warm or cold?
Ya'll are confusing me!

IMHO, it's not a matter of warm or cold oil, just make sure you let it sit long enough for the oil to drain back to the sump. It's OK to check it warm/hot, but I like to let it sit for a while (at least 15 minutes) to make sure I'm getting an accurate reading. Also, I've found that the engine takes less oil that the specs say when it's changed. My 617 turbo spec is 7.9 quarts, but in reality it takes more like 7.5. Normally I put in 7 quarts, start the engine until the oil pressure comes up, then let it sit for a while and check the level to determine how much more it needs.

I would at least bring it back to have it rechecked by your mechanic.

Mismost · #12 04-17-2006, 09:21 AM

A high oil level can also be causing part your oil leaks. The dealer noted my 300td had a "massive oil" leak....it did because they filled it to an inch above the top mark. I drained a few quarts out, refilled to a level between the marks and stopped the massive part of the massive oil leak. She still drips, but she is not puking anymore! I think small drips must be standard equipment on these old cars...no extra charge!

Hatterasguy · #13 04-17-2006, 10:45 AM

Yeah that happend to me when I changed the oil in my 617. With the 603 I add 8 quarts and I'm right on the full line.

With the 617 I added 8 and was probably at least 3/4 of an in over the full line.

I just drove it, she burned it off in about a month. Mental note add 6 quarts next time around!

imagesinthewind · #14 04-17-2006, 11:19 AM

Drained off a quart this morning.
Talked to PO last night and he said he may have not allowed enough time for the old oil to drain out when he changed the oil that morning.
He said it never showed overfull when he did that before so I figure it was a mistake and we drained a bit.
Should also make the leak either stop (there was none before according to PO and his garage floor is spotless) or make it a drip.
Thanks to all!