Oil leak from oil cooler on my 2008 E320 Bluetec

[bhehmann]

Good day.

I detected a pretty sizable oil leak from my 2008 E320 Bluetec. I took it to my indie who told me that it's coming from the oil cooler and that he doesn't have the tools to fix it and I have to take the car to the MB dealership.

Has anyone else here had this problem?

[jcyuhn]

I have not had it yet on my '08, but it is very common on the om642 engine. The parts to repair are not very pricey, but it requires 10+ hours of labor so is a very expensive repair overall. Apologies for being the bearer of unpleasant news, but it is what it is.

Have you tried calling other independent MB shops to find one that knows this problem?

[DDAY]

I had that oil leak problem on a car I purchased early last year. The leak was found in the pre-purchase inspection and the dealer discounted the price another $1,000. The leak was small so I did not have it repaired. At my first oil change, I found the leak had stopped (the belly pan was dry). Two oil changes later I overfilled a small amount---major oil leak from that area---a lot of oil in the belly pan. I removed about a pint of the engine oil and the leak stopped. It has been good for 2,000 miles now. I do not understand the connection between the oil level and a leak at the oil cooler. Last year when the leak was detected, the independent mechanic estimated $1,000 labor to replace the o-ring. He had already made this repair on another car.

2008 MB Bluetec 115,000 miles

[GregMN]

2008 ML320 CDI - Oil Cooler Seals Replacement - MBWorld.org Forums

[masc243]

Replaced Oil Cooler Seals and Swirl Motor on wifes ml320 cdi; om642. Make sure the new seals are Viton; (purple instead of red).
To get to the oil cooler, you will basically be removing everything between the left and right cylinder heads all the way to the bottom of the valley; Turbo all the way forward to front of block.

Its a lot of work and lots of cleaning as you will find the intake manifold and intakes at the heads will be grimed up with sludge from the crankcase ventilation system.

Shops are quoting 10 to 13 hours of labor on this; not sure how they can make money on this. First timers could use twice this amount of time; I might could do it again in 12 hours provided I had no broken bolts and all of the required seals, gaskets, and bolts on hand.

Definitely need some torx sockets and some swivel ratchets to access some of the turbo and exhaust bolts.
Mike

[bhehmann]

Thanks for your replies! I suppose costly repairs is part of driving a Mercedes. Am I correct in assuming that the new seals are of better quality than the original factory seals?

[masc243]

New Purple Viton Seals will likely not leak. Great material that is not affected by chemicals or heat. As long as surface is clean, and cooler is properly torqued, should be no issues.
Have your mechanic take a good look at your turbo inlet seal; replace if at all in doubt as a leak here will drip onto the swirl motor. Oil will make its way into the motor via the connector and cause a fuse to blow, multiple faults and limp mode.
From what I've read, the dealerships will simply want to replace the intake manifold as part of the repair as its going to be extremely caked up with crud. Soak with solvent and power wash will save it (left and right half, separate upon removal).

Best to you,
Mike

[pimpernell]

Originally Posted by GregMN

2008 ML320 CDI - Oil Cooler Seals Replacement - MBWorld.org Forums

Looks like about as much fun as having your wisdom teeth removed. Thanks for the pictures!!!

[Skid Row Joe]

Originally Posted by jcyuhn

I have not had it yet on my '08, but it is very common on the om642 engine. The parts to repair are not very pricey, but it requires 10+ hours of labor so is a very expensive repair overall. Apologies for being the bearer of unpleasant news, but it is what it is.

Have you tried calling other independent MB shops to find one that knows this problem?

Yowzer! Looks like I dodged a recurring bullet by going with the OM648, Jim.

[Skid Row Joe]

Originally Posted by bhehmann

Thanks for your replies! I suppose costly repairs is part of driving a Mercedes. Am I correct in assuming that the new seals are of better quality than the original factory seals?

While I agree, it varies from model to model's repair, it doesn't stop there. The astronomical price of some parts, are another beating you take with a newer MB. Example; a set of MB engine mounts for a W211/$300.00+/set. That's scary high.

[bhehmann]

I had no choice but take it to the dealership. They tore a new @$$ in my wallet to the tune of $3,164.

Now I seem to have a gamey #2 glow plug. I'm thinking the tech buggered something up while fixing the oil leak?

[masc243]

Originally Posted by bhehmann

I had no choice but take it to the dealership. They tore a new @$$ in my wallet to the tune of $3,164.

Now I seem to have a gamey #2 glow plug. I'm thinking the tech buggered something up while fixing the oil leak?

The connectors on the glow plugs pop on with an audible snap. You could check it yourself.
GP Relay is a common failure on these; easy to change.
Mike

[Skid Row Joe]

Originally Posted by bhehmann

I had no choice but take it to the dealership. They tore a new @$$ in my wallet to the tune of $3,164.

Now I seem to have a gamey #2 glow plug. I'm thinking the tech buggered something up while fixing the oil leak?

Unfortunately, unless you're there to witness such an event, it's nearly impossible to know who might be at fault.

My indy identified GPs on my '99 E300 that had supposedly been changed-out by the Mercedes-Benz dealer previously, had not been. However, I had been charged for them to be. It's really frustrating trying to discern who you can trust as a mechanic.

I would ask you to have shopped a lot more indys around the Metro before taking it to the MB dealer. I got several over here in Dallas County that you could have shopped.

[clacker]

There are some interesting thoughts as to the cause of the oil cooler seals letting go. Some blame the quality of the seals and too much heat in the valley. Some say the crankcase vent system is over pressurized and the pressure has to escape somewhere and the oil cooler is the weakest link, another said dirty air filters make that situation even worse...
I can first hand say that the engines do have a ton of blowby from new. And the air filters do get filled up with debris very fast (at least the SUV models), 40k miles is much too long for an interval on them. So each argument has some weight to it.
I have found a supplier selling a full kit to reseal the oil cooler $650 CAD in Toronto, a very complete kit around 40 parts or something like that all OEM parts direct from Mercedes.