I have a 2011 GL350 with 102,000 miles. Purchased new. I use it as a daily driver and also to tow our 30-foot Airstream - I would guess about 25,000 miles of towing in all over the years. I've averaged more than 26 MPG over the lifetime of the GL on the freeway when not towing, and I get about 15MPG when towing.

On the good side, my kids and dog and I just returned from the most epic adventure ever this summer - we visited more than 20 national parks with the GL and the Airstream in a 12,000 mile, two month adventure. What a great country we have.

On the bad side, my OM642 diesel motor continues to be incredibly unreliable. The latest is that I'm getting loud clattering at startup again, which I understand is indicative of the timing chain stretching and/or tensioners failing again. This problem occurred before about 50,000 miles and was repaired at the dealership under warranty. I hear the clattering noise for two or three seconds after startup, and then it goes away, presumably once the tensioners pump up with oil. The clattering noise doesn't occur unless the truck has been sitting for at least 18 or 24 hours. There are no OBD codes stored or pending. I've been changing the oil and the oil filter every 5,000 miles. Here is what it sounds like ->
For the first time since I've owned the GL, I'm not covered under any kind of warranty or extended warranty. So I reached out to MBUSA to the customer advococy team in the hope they will cover the re-repair of the timing chain issue under goodwill. According to MBUSA, first step is to have the dealer diagnose the problem. Of course nothing is ever easy, and even before we start I'm having to negotiate between the dealer and MBUSA on how much testing and what kind of testing is required to diagnose the problem - the dealer wants to do a full set of engine viability tests (leakdown test, compression test, timing diagnostic, etc) and they of course want to charge me for all of this - and the dealer says they want to do this because MBUSA requires it to ensure the engine is viable before authorizing a goodwill repair on the timing chain. I called baloney on this with my service advisor - the engine sounds fine and runs fine and there are no codes and nothing else hinting at any problems like bent valves or timing issues - and I think he was very surprised one of his customers pushed back and knows what leakdown and compression tests are. I think the problem can be diagnosed simply by listening to the video and/or to the noise at startup - so we will see what MBUSA says as I'm included them in a three-way email conversation. My suggestion was that I cover the cost if any to diagnose the timing chain issue, and MBUSA or the dealer covers any additional costs if they want to do further engine viability or other testing. The conundrum is of course that my indy will fix the timing chain for not that much more than the dealer would charge for running a complete engine diagnostic.

I've already had on the order of $50,000 of repairs done on the GL, all covered by the various warranties I've had on the vehicle. Some of these include:

• Replaced oil cooler seals – twice
• Replaced turbocharger
• Replaced timing chain and tensioners
• Replaced rear main seal
• Replaced engine mounts – twice
• Replaced vacuum pump
• Replaced intercooler
• Replaced exhaust hangers
• Replaced Electronic Ignition Switch
• Replaced both front control arms
• Replaced DEF heater
• Replaced passenger side blind spot detection mirror – three times
• Replaced multiple parking sensors
• Replaced both front wheel bearings
• Replaced all four leaking air suspension bags
• Replaced air compressor and valve block

I've ordered a new GLS580 which is coming in late December - my hope is they bite the bullet and fix the timing chain issue to keep me going until the new truck arrives. I think would have been ok with my GL had I bought the 450 or 550 - I love the way the truck drives when it's working, and while I love the fuel economy of the 350, the OM642 diesel motor has just been a complete disaster from a reliability and cost to repair perspective.

All ideas are appreciated. Do you folks agree the noise in the video above is the timing chain stretching / tensioners failing again? Does anyknow know what if any tests, other than listening to it clatter at startup, are diagnostic for this problem? Anything else you would ask / demand that the dealership or MBUSA do?

 

You want ideas? Get rid of it. Any MB diesel built after 2006 is junk. You should already know that by now, with all the repairs you've experienced. It's now 9 years old with 100k+ miles. Things will only continue to fail. Chasing and/or repairing an engine noise at that age and mileage is the proverbial "pissing in the wind." Your 4/50 warranty is way beyond over and you shouldn't have any expectation of MB to pay to fix your well used car.
And yes, you are right, the gasoline version would have served you better. A new GLS may leave you disappointed if you expect to keep it beyond the warranty expiration. It's a brand new model, and you should never buy a brand new model of any manufacture. You'll be the beta tester.

 

Sorry dude. Glad it got you through an epic road trip.

Does the class action decision throw any money your way? Either dump it and keep the money,
or use it to fix it with your Indy, then dump it.
I’d be surprised if your dealer foots the bill for this, but who knows - they might want to keep your business.

These OM642’s are simply not worth fixing.
good luck with the GLS.

 

Sorry to hear of your issues. If my memory serves me correctly, I seem to recall there is an updated check valve that helps the timing chain tensioner hold pressure longer between starts.

With that said, get rid of it when it is fixed. It's always something with the OM642. If you want something more reliable, go with a X166 GLS anything other than the 350. You can get a late model and low mileage MB CPO with some serious warranty that will give you peace of mind for a very long time. Like E55Greasemonkey said, stay away from the X167 for a few years until there is some history of reliability. The launch seems to have been a bit iffy.

 

Option #2. Do nothing. Live with the occasional cold start noise. Your GL isn't worth spending any money on. If the engine blows up, leave it where it died, take your tag off and walk away.

 

@ddruker Great advice from the most seasoned posters on this site. I would do nothing with the current vehicle, and start looking for a known reliable vehicle with warranty remaining - a 2019 GLS 450 or GLS 550.

Doing nothing for me includes not wasting time, breath and energy emailing with, speaking to or visiting either the dealer or MBUSA. They are paid to give you the runaround.

 

Thanks all.

Plan A is to see if they will fix it under goodwill - but not spend too much time on it with them. I think that's very good advice.

Plan B is to fix it myself - it's about $300 in parts plus one special tool to break the old chain and join the new chain - you only have to take the passenger side valve cover off to get to it, which isn't that bad.

Then I expect to keep it around for the next six months or so until get the $3,500ish check from Mercedes as part of their dieselgate settlement. It will be very infrequently driven once my new GLS shows up.

I absolutely agree with all the feedback about getting rid of it and it being a money pit. It's such a shame.

I also appreciated the feedback about getting a CPO X166 instead of a new X167. I'm sticking with the X167 as I really do hate COMAND that badly. Hopefully the major kinks in the 2020's will be worked out in my 2021.