OM642 Mystery exhaust leak
Thread Starter
Member
Joined: Nov 2016
Posts: 90
Likes: 9
From: Barrie, On
GL320 / R350
OM642 Mystery exhaust leak
Hey fellas.
My GL has a mysterious elusive exhaust leak. I can smell it on the passenger side of the engine compartment close to the rear of engine. I can't see any smoke though. I removed the air box and the crankcase breather to get access to the turbo lines and exhaust pipe. No visible leaks though.
I believe this is what is causing my hfm-sfi error also.
Any ideas how to find this leak?
Thanks
My GL has a mysterious elusive exhaust leak. I can smell it on the passenger side of the engine compartment close to the rear of engine. I can't see any smoke though. I removed the air box and the crankcase breather to get access to the turbo lines and exhaust pipe. No visible leaks though.
I believe this is what is causing my hfm-sfi error also.
Any ideas how to find this leak?
Thanks
Junior Member
Joined: May 2018
Posts: 50
Likes: 6
Ml350
It might not be an exhaust leak.
What I like to do is on a cold car is to run a wet dry vac on reverse up the muffler with the other plugged then feel for leaks, but barring that any leaks will have a black sootiness. Common areas are the flexy bits in the manifolds, their circular discs before the y pipe.
Look at your intake system for any oil leaks, oil or diesel leak smells essentially the same to my nose. the last sneaky one I found was the underside of the vacuum pump on the front left of the engine.
Is there any oil under the car? this might require taking off the lower panels.
Do you only smell it while at a stop?
What I like to do is on a cold car is to run a wet dry vac on reverse up the muffler with the other plugged then feel for leaks, but barring that any leaks will have a black sootiness. Common areas are the flexy bits in the manifolds, their circular discs before the y pipe.
Look at your intake system for any oil leaks, oil or diesel leak smells essentially the same to my nose. the last sneaky one I found was the underside of the vacuum pump on the front left of the engine.
Is there any oil under the car? this might require taking off the lower panels.
Do you only smell it while at a stop?
Thread Starter
Member
Joined: Nov 2016
Posts: 90
Likes: 9
From: Barrie, On
GL320 / R350
Update
Finally had some time to look at my GL today.
hooked up shopvac to one pipe and blocked the other. No obvious leaks but I could hear air. So I crawled under and there it was, a massive escape of air at the union between the dpf and the pipe. The clamp looks good. Upon closer inspection, the pipe flange is damaged. Chunks are actually missing. So now the challenge is finding a way if sealing these two pipes together then clamping again.
Dan
hooked up shopvac to one pipe and blocked the other. No obvious leaks but I could hear air. So I crawled under and there it was, a massive escape of air at the union between the dpf and the pipe. The clamp looks good. Upon closer inspection, the pipe flange is damaged. Chunks are actually missing. So now the challenge is finding a way if sealing these two pipes together then clamping again.
Dan
Thread Starter
Member
Joined: Nov 2016
Posts: 90
Likes: 9
From: Barrie, On
GL320 / R350
Update 2
The flange was to badly damaged to repair and a whole new DPF is cost prohibitive, so I wrapped in spider patch exhaust repair and then sealed over with fiberfix high heat. Kind of redneck I know, but it works like a charm.
Interestingly though, my HFM-SFI error is still around. Can't shake it.
The flange was to badly damaged to repair and a whole new DPF is cost prohibitive, so I wrapped in spider patch exhaust repair and then sealed over with fiberfix high heat. Kind of redneck I know, but it works like a charm.
Interestingly though, my HFM-SFI error is still around. Can't shake it.
Member
Joined: Dec 2019
Posts: 187
Likes: 45
2008 R320 CDI 4MATIC
Update 2
The flange was to badly damaged to repair and a whole new DPF is cost prohibitive, so I wrapped in spider patch exhaust repair and then sealed over with fiberfix high heat. Kind of redneck I know, but it works like a charm.
Interestingly though, my HFM-SFI error is still around. Can't shake it.
The flange was to badly damaged to repair and a whole new DPF is cost prohibitive, so I wrapped in spider patch exhaust repair and then sealed over with fiberfix high heat. Kind of redneck I know, but it works like a charm.
Interestingly though, my HFM-SFI error is still around. Can't shake it.
I would remove/delete the DPF. Cost less and will run much better, both performance and mileage. And no more regeneration.
Regards
Joseph~
Last edited by Joseph~; Jan 24, 2020 at 12:56 PM.
MBWorld Fanatic!
Joined: Jan 2009
Posts: 9,224
Likes: 1,798
From: V E G A S
1922 Ford Model T / no OBD
I don't know about running better.
The car I had DPF deleted makes less mpg than the one with DPF still working, while legal issues are concern.
What flange was damaged? I think any muffler shop can weld metal damage.
Can you post a picture?
The car I had DPF deleted makes less mpg than the one with DPF still working, while legal issues are concern.
What flange was damaged? I think any muffler shop can weld metal damage.
Can you post a picture?
