Hello All,

I'm looking for some help/advice on a scenario that I found myself in yesterday evening. 2013 GL350, 120K miles. At a fork in the road. I bought the vehicle about a few weeks ago, have driven about 700 miles.

No issue until here was a knocking sound and what seemed to be a loss of power. I drove it home about 4 miles and called for a tow truck to take it to the dealership. I didn’t feel comfortable driving it any further.

Was told that it was an injector + injector seal and would be covered under the Bluetec warranty. While they were in there they found other things: oil cooler leak, axle boot, which I agreed to pay for.

After replacing the injector/seal, the engine came back with an issue and was identified as no compression in that cylinder. First questions, why was this diagnosed as just the seal? Should there been further exploration at this point?

So, with no compression in that cylinder, they said they needed to perform a borescope. This came back inconclusive. They were unable to see/identify if the issue was with the head or the block/cylinder. They did not see any scoring on the cylinder heads. Second question, does this sound right?

I was told that if it’s in the cylinder head, the issue is covered under the warranty, if it’s something in the block itself, both the exploration and the potential repair are not covered. Where I’m at now is, they need to do something called an R&R where they remove and replace the cylinder head/gaskets at $5,200. If they determine that the issue is the cylinder head I’m covered… if it’s something else, I paid $5,200 (plus previous expenses) to find out the engine is bad…

I guess what I’m asking:
-Does this all seem correct?
-Understanding there is no way to definitively determine this. What is the probability that the issue is with the cylinder head vs something more serious? The service manager was unable to comment on that.
-What would you do in this scenario??Any help/advice is greatly appreciated. Thank you in advance!

 

A leak down test should identify the cause of "no compression". As an aside, I'm wondering how they diagnosed a bad injector on a cylinder with no compression...

 

I don't know how the initial diagnosis was made. But I would assume there should have been a more comprehensive diagnosis as well initially?

Is a leak down test something that's common procedure at a dealership?

Thank you!

 

Get yourself advanced scanner and do DIY troubleshooting as even with AEM warranty, dealer can flush you saving account pretty fast.
Good scanner will allow you to do "smoothest test" who come in 2 versions.
1 is simulated compression test,
2nd is testing injectors.

 

Unfortunately the om642 is a garbage engine and you should have done some research before buying one.... especially at 120k miles. Cut your losses now, it will only get worse as the miles accumulate. It will never be a reliable vehicle.

 

Thank you for the helpful response.

 

Can you elaborate on this?? I'm curious if this means there was some sort of incompetence or ...? Thank you!

 

Thank you. Do you have any recommendations on what advanced scanners I should be looking at? Model #s?

 

sprinter forum has designated scanner section, what would give you lot of read.
Lately AP200 or ThinkDiag have best recommendations. but it is hot industry, so new stuff comes every few days.

 

So they're saying a leak down test was performed and is still inconclusive that they need to pull the head... does this seem right?

 

Nope. You can do much more easy testing before pulling the heads.

 

Something sounds fishy. The dealer can test engine compression by simply running a program off their star diagnostic software. They are able to provide you with printoutout of the results of that test that includes the vin of your car.
they can also run a test utilizing their mercedes star software that checks all the injectors if they're are running within spec.

They could initially have seen black residue around the culprit injector without presurizing the cylinder but if someone told me that rhe engine is making knocking sound and runs poorly, id be checking compression on all cylinders 1st.

 

And in regards to this question:

So, with no compression in that cylinder, they said they needed to perform a borescope. This came back inconclusive. They were unable to see/identify if the issue was with the head or the block/cylinder. They did not see any scoring on the cylinder heads. Second question, does this sound right?

Not sure why didn't they simply check compression of that cylinder. To do that, they place the culprit cylinder at the top of its travel, they remove the glow plug and pressurize that cylinder with air. The guage tells them what air pressure is at the supply and also the air pressure at the cylinder. The difference is the leak. You then listen to where the air is leaking at: intake, exhaust, etc... so if air is escaping via intake or exhaust ports, it's the head issue.
there is absolutely no need to remove the head to tell you this so sounds to me like they are playing you. Sorry

 

Yeah that dealer is feeding off your lack of knowledge. Wouldnt trust them with anything from now on. Ones like that are why everyone hates dealers and most of them are like that.

 

This is the only correct response.

 

Take the exit at the fork.

 

You guys should marry each other.
OM642, when require higher maintenance, than other MB engines, has been in production for well over 20 years (I think it still is?).
Would that indicate something?

 

The last good diesel engine sold by MB in the U.S. was in 2006.

 

No, it doesn't. You initially said "no compression". No compression means as the piston goes up in the cylinder, all the air leaks out. A leakdown test involves metering compressed air into the cylinder and measuring the rate at which it leaks out. A side benefit is you can listen for air at the tail pipe, intake manifold, and crankcase vent to identify the cause of the leak. Did they tell you what the results of the leakdown test were? It'd be something like 65/80 (or maybe 80/100 depending on how they're trained.)

(Oops... I see Goodby Honda already answered.)

 

The OM651 is a joke?

 

I wouldn't own one. "5 starts remaining" Just wait for it........

 

 

Yeah will see what happens, made it 97k miles so far. Gets above 40mpg which I dont think any previous MB engine has. Ofcourse think your talking about the emissions system and not the engine but not sure.

 

OM651 is a disposable engine.

 

What engine in USA is not disposable today?
Strange that after taking the engine apart and determination of oil pump failure, the mechanic did not attempt to investigate what cost the failure.
I had oil pump failure on OM603 engine. Good thing, it did have oil pressure gauge and it happen in front of my house, so the engine survived.
I found infamous vacuum pump bearing ball, who was left by PO and after several thousands miles the ball managed to wear a hole in oil pump screen, entering the gears.
Did I call OM603 a rubbish?