2009 Mercedes E320 cdi V6 oil leak! 😩

[Lewst89]

E320 OM642 engine.
Hoping someone may have experienced this and can point me in the right direction. Currently trying to trace an oil leak. Been leaking for a while as the underside is covered. Sorry for the quality of the pictures but basically it seems to be starting just below the starter motor. Slight leak from dipstick seal aswell. Would it be the 2 piece sump needs removing? Its so compact and working on the floor makes it that much more difficult. Feel like pulling my hair out so fingers crossed someone will know the answer or experienced it before

 

[Lewst89]

Still cant put my finger on it, its either the sump or oil cooler seals, cant tell if its coming from behind the starter or justr below on the sump join

 

[DSM10000]

Can you clean the area of oil and then try to see the origin.

 

[Lewst89]

Can you clean the area of oil and then try to see the origin.

iv tried cleaning it up but with all the pipes and cables and limited space im finding it hard to pinpoint, i cant decide if its the sump join or its working along that edge from behind the starter (V drain point). Im thinking its the oil cooler seals, just hoping its not

 

[MrGreedy]

On the OM642, regardless of variant, at something like every 10 years or 60-100k miles, I would expect the oil cooler seals to need to be replaced. When were these last done?

 

[DSM10000]

iv tried cleaning it up but with all the pipes and cables and limited space im finding it hard to pinpoint, i cant decide if its the sump join or its working along that edge from behind the starter (V drain point). Im thinking its the oil cooler seals, just hoping its not

You are doing well to try!

Perhaps get it to a local garage that you trust and get in on a ramp?

 

[Lewst89]

On the OM642, regardless of variant, at something like every 10 years or 60-100k miles, I would expect the oil cooler seals to need to be replaced. When were these last done?

Honestly i dont know, this is my dads car. Hes had a few issues so i have just replaced the 2 front engine mounts, both front lower bulljoints and control arms, brakes all round and turbo actuator. oil leak is the final job. hes had it about 4/5years now and probably covered a good 60k+. Id hazard a guess that there original its sitting on around 120k miles i believe.

 

[cylaptor]

oil cooler seals are the problem. For changing it you need 10+ hours for a professional mechanic. This oil cooler seals are pain in the ass at V6 cdi engines.

 

[Tuercas viejas]

Try to be aware that the leakage MAY be from the seals and flooding the valley.
Only by power washing the area can you determine the source.
The rear main seal plate/cover assy has been up-dated with a completely new shape/design and even with that we have found the seal itself has worked loose in the plate causing a leak.
Accurate diag is required.
Tuercas viejas

 

[Tanny100]

Get some degreaser and spray liberally. The wash off carefully. Even better try not to use water but a solvent which will evaporate and not cause other issues

 

[Carlos2k]

As said, id go with oil seals.. take some intake gubbings off the top of the engine and look in the v with a torch, you'll likely see a bath of oil, the drain hole is at the back.

I did mine when i had the OM642, took a while!

 

[Lewst89]

Sorry for the delayed reply, i checked it more and can confirm the oils coming from the rear drain off for the V, ordered the seal kit in and replacement exhaust bolts. Managed to squeeze a couple of hours and got quite abit removed this evening.

 

[mioba]

Make sure you take pics as you go, There will be alot of seals to replace. The 642 is like an onion, layer after layer after (and so on).
Good luck

 

[Carlos2k]

be sure to get replacement gaskets for the intake manifolds, egr etc. Don’t want to find you a need to the job twice!

 

[Carlos2k]

Oh and most certainly the o rings on the fuel return lines! If you havnt pulled them off before they’ll most definitely leak when you put them back. Saves a world of pain.

 

[mioba]

The total cost of seals / gaskets, for want of replacing oil cooler seal (few pounds) is over a hundred pounds

 

[MrGreedy]

ID Parts (USA I know) has a good indication of the seals, screws, bolts, bits and pieces you need:

Oil Cooler Seal Kit (OM642)

Full set of replacement seals to complete an oil cooler seal replacement. Includes all gaskets and seals for the items that must be removed in order to access the oil cooler. Latest version! ...

www.idparts.com

Also check the list of recommended items at the bottom of the page that you should be changing at the same time.
As well as a new oil cooler, I also changed the swirl flap motor when I did mine, as I want to spend this amount of time (and money) only once until 6+ years time when the job needs doing again.