Om651 Air leak locations

[Don212]

Hi All

Can someone give a definative list of all possible air leak parts/sensors that could fail on a om651 please.

Car has been in mechanics for 3 months and we are out of ideas on what could be causing my recurring air leak.

Cheers

 

[Don212]

p.s would a broken vacuum line trigger the eml?

 

[Tonygw]

on some, the inlet manifold can develop a hairline crack which is not easy to locate, and also there is a bolt that can snap holding the inlet manifold to the block, (known issue) Both will trigger an EML and cause running issues. Are you using a Mercedes specialist or a general garage?

Have you access to STAR (Mercedes official diagnosis, interrogation software) most generic garages wont have this.

other places are the boost pipes can also split, not easy to see, but quite a common failure. have you got access to a smoke tester? as that will make the location of the leak much easier.

 

[BlackC55]

Boost pipes, inlet manifold, EGR valve are the common areas.

Has it a boost leak code?

Has a smoke test been done?

If there is no leak and you have a boost leak code you need to vac test all of the transducers. There are 3 of them on a 651 engine. One or two will be faulty I suspect.

 

[MSG2004]

on some, the inlet manifold can develop a hairline crack which is not easy to locate, and also there is a bolt that can snap holding the inlet manifold to the block, (known issue) Both will trigger an EML and cause running issues. Are you using a Mercedes specialist or a general garage?

Have you access to STAR (Mercedes official diagnosis, interrogation software) most generic garages wont have this.

other places are the boost pipes can also split, not easy to see, but quite a common failure. have you got access to a smoke tester? as that will make the location of the leak much easier.

I have that engine in my Merc and that was one of the many reasons I was watching a Youtube video vlog by SPR-Autos IIRC - (I could not find the video) that was testing for leaks as you stated with a smoke machine

PS - I watch so many videos and it could have been someone else. It was a cracked hose in the video car was about 15 years old I think