Opinions please: 2008 ML320 CDI 4MATIC
 

Hi guys,
My 73 y/o mother is finally replacing her 10 year old ML 320 that she bought new. My question is should I buy it from her, knowing it's full history and it having been the quintessential little old doctor's wife's car? She mostly drove it around town in Phoenix during it's 122k miles, with semi-frequent drives up to the cabin in Flagstaff, 2 hours away. Other than normal wear and tear, it has a front-end clunking over bumps that her independent guy can't seem to locate, though it is quite noticeable. Also, it just had a $1,000 oil leak repair done before Christmas, but I'm not sure if it was the infamous oil cooler leak, as she can't seem to find the repair order at the moment. I just remember a lot of oil on the garage floor a few months back. It still has a very small leak, like a couple tiny drops on the garage floor, but she was told this should clear up within a few weeks after the repair. Also, should I be worried about what appears to be oil leaking up and over that trap oxidizer looking thing behind the turbo? I can't tell if it's old oil and isn't a problem anymore. Anyway, I'll try to find out what was actually replaced in the next day or so. Thanks - Mike

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I would say go for it.

Nice car - you know the owner maintenance records etc. Worth it for sure.

Have a dealer diagnose the issues perhaps over a "63 point inspection" and put that into the purchase price. There will be a list of things that you'll want fixed, especially the clunking noise.

$1k is far too low a price to be the oil cooler leak. Dealer pricing for that repair is typically in the $2500 range, and even the lowest cost Indy would be above $1500. Has it had the intake flap motor replaced? That's another $2500 repair which they all need. Especially if your oil leak fix was the y-tube intake pipe and associated gaskets.

I vote no. As a former om642 owner, diesel head, and MB fanboy, my observation is that the cost of ownership of this engine/driveline just doesn't make sense. Too many common and expensive repairs on this engine.

aluminum block diesel? no thanks, and V6,shake itself to death

I have read where two v8 mercedes diesel engines with aluminum blocks were **** to.The 4.2 a 5.0 diesels.

It is hard to give advice without knowing what you will pay for it.

OK I will weigh in on this one since I own one of these.

I have lived the oil cooler seal adventure. http://www.peachparts.com/shopforum/diesel-discussion/363973-journey-into-infamous-om642-oil-cooler-leak-4.html#post3633880 It is not the doom and gloom scenario that others make it out to be. Yes a dealer or good Indy will charge north of $3k for this work, but if you are reasonably handy, have proper tools, and can pay good attention to detail and follow instructions to the letter (WIS spells it out in total detail) it is not a bad job. I did mine for less than $1000 including purchasing some special tools. I did mine in the fall of 2015, my sons have it up at school, and it has not leaked a drop since. There is another online retailer that has the full kit of parts needed including the swirl flap motor, crankcase breather puck, and every gasket and seal you’ll need for about $600. I also bought a new air intake Y-pipe since mine was cracked at the turbo inlet (typical mechanic mistake to overtighten that band clamp, or not releasing it correctly when changing air filters). You will need an injector line wrench and a connector plug puller pliers, good (NOT Harbor Fake) E-torx sockets, and good torque wrenches. I could have done the job completely in a long weekend but for waiting for the special tools.

Addressing the oil cooler takes care of the major issue on these engines. I did read about another OM642 owner on this board, who had leaking injector seals, but that is the only instance I have heard of this happening. Easy enough to keep an eye on, you just have to remove the sound padding over the injectors and inspect the area.

The one big maintenance thing you have to ignore the factory recommendation is to change the air filters at 2 yr/20k not 4 yr/40k like they recommend. The differential pressure builds across the dirty air filters and it causes the engine to start sucking air and oil through the crankcase breather which exacerbates the oil leakage problem. I suspect this may be your $1000 repair, which takes about a half hour and $100 to change the crankcase breather puck yourself. Note that changing the air filters requires adapatation by Xentry.

I have 148k on my vehicle and it’s been great so far. Purchased at 106k in summer of 2013 from local MB dealer. Only failure I have had so far, beyond the oil cooler seals, is the steering rack started leaking about 15k miles ago. I had an Indy replace since I don’t have a lift, and you need one since you have to drop the transfer case to get the rack out.

I think these are going for the low teens on the used dealer market. As MB has pretty much given up on diesel in the US market I think they will become more desirable. People don’t realize that every gas powered MB requires Premium gas which in most places is more expensive than diesel, and you get a 25% MPG boost on diesel over gas.

I would buy another one of these again especially if I knew the history. And I would do the oil cooler seals on principle unless I had documentation that it had been done by the dealer or a competent Indy (ex-Mercedes dealer tech).

If you end up buying it then go on ebay and look for seller gordysgadgets and pick up a Xentry system for $500. It will totally pay for itself.

Well *****...
 

Thanks guys for the input, but unfortunately it’s now out of my hands. Called my parents today to ask them something, only to find out they were at the Lexus dealership signing on the dotted line for a new RX450h and trading in the ML320. The RX is ugly as all hell, but probably very reliable. C’est la vie. If anyone wants the ML, Earnhardt Lexus of Phoenix will be selling it or sending it off to auction. Thanks - Mike

If they traded it in they most likely got way less than they could have by selling it outright. They should have just let you pay them trade in value.

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Tell me about it... :-/

Your parents could have sold it to you on the spot at what the Lexus dealer allowed them on trade in. Likewise, we forum members could have bought it at that price as well. Regardless what the Lexus dealer wanted. Your parents (were) in the decision catbird seat. Even gotten the sales tax credit, IIRC how it works. Would have cost them zip. It doesn't sound like your communications are open with them. Too late now, though.

You never said how much $$$ they wanted to sell it to you for.

No kidding......something's not right here with the deal......