Odd Noise

[SJHE]

Evening,

I have an S204 C220 CDI with the OM646 engine and 5 speed auto box. This last week I've noticed a sort of hissing noise in the cabin when the engine is under load/acceleration. The noise can only really be heard on the drivers side and is present at all acceleration speeds but disappears as soon as you take your foot off the pedal.

The turbo is located on this side of the vehicle so I was thinking it may be a boost leak of some sort but a scan has turned up no codes.

Before I go ahead and let a garage investigate, probably with a smoke or pressure test, is there anything obvious I could look out for or potentially any other fault that might give these symptoms?

The scan showed the DPF to be at 16% so unlikely it's been caused by a blockage/excess back pressure.

Thanks in advance.

 

[alexanderfoti]

Split boost hose, the one on that side of the engine is common to go first.

Will often not log faults until it gets really bad.

 

[SJHE]

Split boost hose, the one on that side of the engine is common to go first.

Will often not log faults until it gets really bad.

Thanks Alexander.

Just to clarify, when you say boost hose are we talking intercooler hose like the one in the photo attached?

Would there be an underlying reason for it to fail or is it likely just normal wear and tear?

Regards

 

[alexanderfoti]

Just wear and tear.

Yes like that.

It's likely to be one of those. There are a few other places so you will need to check.

 

[SJHE]

Would you suggest having a garage do a smoke test first or just replace the intercooler hoses and go from there (which I can do myself)?

 

[alexanderfoti]

Yes absolutely (smoke test). Sometimes this won't find small boost leaks and you have to pressurise the intake.

 

[SJHE]

Super, appreciate all your help. Thanks.