OM642 Oil Consumption - PeachParts Mercedes-Benz Forum

spark3542 · #1 02-28-2019, 01:22 PM

My new-to-me GL350 is consuming oil at an alarming rate...probably a quart about every 300 miles!

I don't know whether the dreaded oil cooler seal has been changed yet, so I assume I have that to look forward to, but there is not a drop of oil on the garage floor.

My old-school training says there's only 3 places oil can go...the floor, into the coolant, or get burned. With no evidence of floor or coolant, I assume it's burning it. However, no smoke cloud while driving, and the back lift gate is not unusually grimey.

Engine bay is clean.

I know 648's like the back of my hand, but the 642 is new to me.

Any insight to my oil consumption problem?

tjts1 · #2 02-28-2019, 01:32 PM

This engine sounds like a nightmare.

jay_bob · #3 02-28-2019, 02:46 PM

Pull the y-pipe off the turbo and see if there is a ton of oil there. A little bit (like a few drops) is normal.

The crankcase breather can fail and suck oil into the engine. Cheap and easy to change.

You have a 2011, that *should* have the updated oil cooler seals.

Diesel911 · #4 02-28-2019, 04:14 PM

I am not sure what time of fuel injection pump you have. If it is a separate fuel injection pump that is lubricated from the engine oil people have said if the little O-ring in the Fuel Supply/Lift Pump goes it sucks oil out off the Fuel Injection Pump and it ends up burned as fuel.

Valve Guides and or valve stem seals.

Diesel911 · #5 03-01-2019, 12:52 AM

Does your exhaust smell as if you are burning Oil? Is there any tail pipe smoke?

You did not say if you were using synthetic Oil or not. Members have claimed that using synthetic Oil freed up piston rings but you needed to drive like 2-300 miles before the effects are noticed.

If your scraper ring and the oil rings are not expanding properly they won't scrap the oil properly off of the cylinder walls and the oil can burn.
Post #20 synthetic Oil frees up Piston rings and gets rid of Blow-by.
http://www.peachparts.com/shopforum/diesel-discussion/323811-best-way-reduce-blowby-15w-40-synthetic-motor-honey-2.html

DDAY · #6 03-01-2019, 11:00 AM

The fuel supply (lift pump) is in the fuel tank. The high pressure fuel pump is connected to the front end of the left side cam shaft and it discharges fuel into the left side fuel rail. The right side fuel rail is supplied with fuel through tubing that connects the left and right side fuel rails together. Not likely that fuel system is pulling in engine oil since the fuel pressures are rather high.

Diesel911 · #7 03-01-2019, 02:39 PM

Quote:

Originally Posted by DDAY

The fuel supply (lift pump) is in the fuel tank. The high pressure fuel pump is connected to the front end of the left side cam shaft and it discharges fuel into the left side fuel rail. The right side fuel rail is supplied with fuel through tubing that connects the left and right side fuel rails together. Not likely that fuel system is pulling in engine oil since the fuel pressures are rather high.

My thanks because I just don't know much about the newer Mercedes.

spark3542 · #8 03-01-2019, 06:30 PM

I use Rotella T6 synthetic 5-40 oil exclusively. I have used exactly the same oil in my 05's for well 200k miles now, changing it only every 13,000 when the dashboard chirps at me.

No noticeable smell or visual from the tailpipe.

I'll check the breather.

Any other ideas?

Thanks

Diseasel300 · #9 03-01-2019, 09:31 PM

Oil will be going one of 3 places. Outside the engine in the form of a leak, inside the engine in the form of burning oil, or into the cooling system (blown head gasket). It will not just magically disappear.

If the engine is consuming the oil at the rate you claim, you'll smell it. You bet. You'll also have that blue haze out the exhaust pipe. A possibility is that you have a turbo seal that's bad, and it's dumping in the cat or muffler. You'd expect to have smoke or power loss issues if so.

GregMN · #10 03-01-2019, 11:00 PM

Quote:

Originally Posted by Diseasel300

Oil will be going one of 3 places. Outside the engine in the form of a leak, inside the engine in the form of burning oil, or into the cooling system (blown head gasket). It will not just magically disappear.

You forgot: out the exhaust via the turbo seal... like magic...

MB140300SD · #11 03-01-2019, 11:32 PM

Quote:

Originally Posted by spark3542

I use Rotella T6 synthetic 5-40 oil exclusively. I have used exactly the same oil in my 05's for well 200k miles now, changing it only every 13,000 when the dashboard chirps at me.

No noticeable smell or visual from the tailpipe.

I'll check the breather.

Any other ideas?

Thanks

That is the wrong oil for the 642. You must use M1 ESP Formula M, Kendall GT1 or the like.

pawoSD · #12 03-02-2019, 02:47 AM

Quote:

Originally Posted by spark3542

I use Rotella T6 synthetic 5-40 oil exclusively. I have used exactly the same oil in my 05's for well 200k miles now, changing it only every 13,000 when the dashboard chirps at me.

No noticeable smell or visual from the tailpipe.

I'll check the breather.

Any other ideas?

Thanks

That is very very much the wrong oil for that engine!!

You should be using something like Liqui Moly 2039 or the above mentioned Mobil 1 ESP!

The oil you are using is both wrong for the engine and horrible for the exhaust system.

As for the consumption....a quart per 300 miles is crazy...if you are not familiar with working on the vehicle I'd be taking it to a shop to be checked out asap before something real expensive gets destroyed.

Diseasel300 · #13 03-02-2019, 08:35 AM

Quote:

Originally Posted by GregMN

You forgot: out the exhaust via the turbo seal... like magic...

Cute, but re-read my post. I didn't forget, you didn't read.

DDAY · #14 03-02-2019, 10:59 AM

Clogged air filters can increase oil consumption. The turbo is pulling in air through the filters but if there is not enough air flow, it will pull air from the crankcase via the crankcase ventilation system.

GregMN · #15 03-02-2019, 12:55 PM

Quote:

Originally Posted by Diseasel300

Cute, but re-read my post. I didn't forget, you didn't read.

Ya. Evelyn Wood failed me again....