OM642 Oil Cooler Seals at 150k miles?? - PeachParts Mercedes-Benz Forum

87tdwagen · #1 03-12-2021, 11:19 AM

Hi All,
Just recently picked up a 2008 Jeep Gran Cherokee CRD with the OM642. Unfortunately the used car dealer had no service records or maintenance history. This was a 1 owner car though, and was a trade-in. I do have a small oil leak, that needs to be investigated further. As far as I can eyeball, it is somewhere from the middle to rear of the engine. The bell housing seems dry. First thought Oil cooler seals.

Questions:

1. From what I've read these tend to fail in the 70-80k mile range. Have any of you had these fail much later than that? Say at the 148K miles like I have now?

2. I have not been able to find consensus on when MB/Jeep may have addressed this in production maybe 2012? Any idea of when service shops may have switched from the orange seals to the viton purple ones?

3. I'm trying to assess whether this job may have already been done on mine given the mileage. Or possibly have been serviced, but replaced orange with orange seals sometime in it's life and they are now due again...arrrg.

Luckily the leak is currently small. I have also noticed that the intake tube has been upgraded to the newer style with the black seal, and the turbo area seems to be fairly dry and oil free, so the PO has had some work done on this engine, just not sure how much.

Any advice or insight before I have to tear into this further would be appreciated. I will be doing an oil change, and while at it will have the lower cover off and may be able to better assess the source of the leak, or at leas clean up the area to monitor down the road. Just curious as to what other have experienced when buying a higher mileage OM642 and what types of leaks they encountered.

TIA

87tdwagen · #2 03-17-2021, 03:09 PM

Did an oil/filter change today and had the lower cover off to better assess the oil leaks. Hard to say, most looked old, caked in dirt/grime ,looks like residual oil from a previous elephant hose leak as well as oil filler tube/cap leak. Cleaned up the underside of the engine as well as the chassis cover and will monitor for trails of an oil leak.

In the mean time, as I'm sure several E-Class and ML/GL owners have approached the 150k mile range, is there anything to be expected soon on this engine in terms of wear/tear?

My timing chain tensioner is showing the oil spray hole, not sure if the stretch is bad or if this is normal, she runs otherwise fine and no codes. Is there an easy way to check chain stretch? on the OM603, it's a breeze.

TIA

jay_bob · #3 03-19-2021, 06:55 AM

At 150k it almost certainly would have had oil cooler seals done by now or it would be leaking like a sieve. 2008s definitely had orange seals.

A few suggestions on proactive things to do with the engine that are not terribly expensive and will save you lots of trouble later. I have two 2008 642s, my two college aged sons are driving my wife and my hand me downs, and these are things I have had to do on both cars (or need to).

- Fuel filter, be sure the hoses are not weeping (had to replace on both cars). Check for fuel accumulation on top of the filter housing. May need to replace the water in filter sensor, it gets a crack in it and starts leaking.

- Oil filter tower, there are 2 gaskets, one against the block and the other in the middle of the neck. The one against the block is available at the dealer the neck gasket is not (they want you to buy a whole new tower) but Dorman makes a replacement neck gasket.

- Belt tensioner and pulleys, it's one of those things that just wears out and will leave you stranded.

- Return hose assembly, another one that will get you out on the road.

- Alternator, had to replace one already and the other is starting to squeak at startup. Get an original from the dealer only, parts store alternators are trouble. Found out the hard way on that one.

87tdwagen · #4 03-19-2021, 04:37 PM

Thanks Jay_bob,
Great tips. Changed fuel filter today which hadn't been done in a while. Questioned the fuel feed hoses and have them on my to do list, I assume any fuel hose will work since these are low pressure.

While the filter was out, inspected the v well as best as I could, didnt see any accumulation of oil, and noticed that tge swirl valve motor had been replaced, prob due to the elephant hose leak and update. A few mounting bolts were loose and one of the turbo mount bolts was missing. Obviously has been worked on.

Tried the 4.7k resistor on the swirl motor, but threw a check engine light and limp home mode. The error was p1020? Too much resistance? I cleared it for now and plugged the swirl motor back in, all good. Hoping to deactivate tge swirl, egr and dpf with a tune in the near future.

Will also put tensioner, pulleys and belt on my list per your suggestion.

Always welcome any guidance, this is my first OM642

87tdwagen · #5 09-08-2022, 04:40 PM

Update 158k Miles

Sure enough a growing oil leak lead me to finally address the oil cooler seals. Sure enough, they were the old Orange seals. I assume that these had been replaced before, probably sometime at the 75-80mile mark 2015 ish and probably were, I could tell that there had been prior work done to the swirl flap and turbo has at some point been replaced, so I imagine the seals were done by the PO. If they are "original" then they got a long life, but likely been replaced before.

Point of bringing this up, is that there are probably several OM642s that have had the seals done in prior years, but with the old orange seals and will need to have them done again to finally correct with the purple viton ones. I truly hope the new purple ones last, even though more experienced now, I wouldn't want to go thru that process again.