E350Cdi - Air Noise After Filter Renewal

[MrGundam]

I replaced my filters at the weekend with genuine MB ones along with some exhaust gaskets (cat to DPF - NIGHTMARE!, and EGR from exhaust y piece gasket.

I noticed today that under hard acceleration I can hear a rather loud air noise. I assume it is the new filters making it more pronounced but can't help but worry if I have seated the cat to DPF correctly and have an exhaust or some kind of boost leak. No exhaust smells in cabin or change in tone nor loss of power I notice so just wondered if anyone had similar experience?

 

[KennyN]

Sounds like more of an induction leak opposed to an exhaust leak , which would be evident at idle accompanied by the smell of exhaust gasses.

I would revisit the air filter replacement job and make sure the airbox lids and associated pipework are fitted correctly and in good order.

K

 

[MrGundam]

Sounds like more of an induction leak opposed to an exhaust leak , which would be evident at idle accompanied by the smell of exhaust gasses.

I would revisit the air filter replacement job and make sure the airbox lids and associated pipework are fitted correctly and in good order.

K

Annoyingly it has had its air filter screws over tightened at some point in it's life and they dont bite as they should. Wonder if there is a way to fix with oversized screws / some kind of plastic weld or if it might need replacing.

 

[KennyN]

Annoyingly it has had its air filter screws over tightened at some point in it's life and they dont bite as they should. Wonder if there is a way to fix with oversized screws / some kind of plastic weld or if it might need replacing.

Do the screws go into a threaded metal insert or just into the plastic ?

If they go into the plastic only you could put a piece of cable tie into the hole and screw into that , this may let the screws get a grip.

Could you fill the holes with some kind of filler (araldite) / hot glue then drill a pilot hole then screw into that ?

Stripped metal inserts may be a bit more of a faff to repair.

K

 

[MrGundam]

Do the screws go into a threaded metal insert or just into the plastic ?

If they go into the plastic only you could put a piece of cable tie into the hole and screw into that , this may let the screws get a grip.

Could you fill the holes with some kind of filler (araldite) / hot glue then drill a pilot hole then screw into that ?

Stripped metal inserts may be a bit more of a faff to repair.

K

Great ideas! They are plastic so I will try the methods you mentioned before sourcing 2nd hand set. Thanks for the tips.

 

[BigJase88]

Great ideas! They are plastic so I will try the methods you mentioned before sourcing 2nd hand set. Thanks for the tips.

Bigger diameter screw is your friend

 

[MrGundam]

Bigger diameter screw is your friend

They are an odd thread though so wouldn't know where to start

 

[MrGundam]

So turns out it is leaking from the Cat to DPF clamp!

I had struggled for over 3 hours last weekend to get everything to align with the cat, turbo and DPF and get the clamp on after replacing the cat gasket that goes between the DPF:

I thought I have finally got the clamp on given the lack of space and visibility but have noticed an air leak noise when under heavy load and high RPM. No exhaust smell in cabin but after looking about today I can see a lot of soot in the surrounding area from what I am 90% sure is the area of the cat to DPF.

I can only assume the securing clamp wasn't seated correctly.

The problem is the cat and DPF join is much tighter due to the new sealing gasket and with the lack of space and stiffness of the clamp it is very hard to get them to align and see they are aligned.

My process was:
1) Bolt cat to turbo as that is not negotiable in terms of play
2) Loosened all the DPF mounting bolts to give it some wiggle room
3) Use a longer bolt to help close the clamp

It was all very tight and impossible to see what I was doing at the back of the engine.

I wondered if anyone could advise the best method to getting the DPF and cat aligned and clamped. Unfortunately I don't think the DPF and Cat can be secured out of the vehicle and fitted as one so needs to be done in situ some how.

Advice appreciated!