[Murphyslaw]

Hi Guys,

I knew I shouldn't have attempted to do anything with my car!
This morning I replaced the EGR thermostat in my car, which hasn't cured the low temp thing..

Took it out for a 25min test drive came back and I can here what can only be described as slow drum beat. Very quiet though. Can't hear it when the engine is revved. Now I am super paranoid about what this could be.

A couple of things when wrong whilst doing the egr swap. First forgot to put the O ring on the egr so it pissed cooled first start up. Second I managed to launch my screwdriver with 10mm socket bit in the end up in the air and lost the 10mm bit in the engine bay. Sure it fell down into liner at the bottom but can't 100% be sure. It fell to the right hand side of the engine looking at it from the front. There is no belts or turbos that side so thought it would be ok to test drive.

To be honest I thought it would cause more of an issue when I started it up if it had got anywhere dangerous.

I know this is a stupid thing to do but I am pulling my hair out!!

Any recommendations?

[Dan-danGT]

Can't you take the liner off? I don't understand why everyone surgest egr stat first as it never helps it's always the main stat I have found

[Murphyslaw]

Yeah think I am going to try that in a bit.
The noise appears to only happen after the car has been on for a couple of mins.
Just went back out and took the cover off before I started to see if if was anything, made no difference.
Started it and no noise, after a couple of mins it was back.

I started with the EGR as that is what seemed the easiest to do and if that sorted it would have saved me a fair amount of cash.

[bazz780]

This is the route i took, and it cured my low running temp issue,

Are you sure you put that little oil pipe fitting back in and didnt end up cracking it?

[bazz780]

Also check coolant level and oil level in case

[makkan00]

Try to bleed again. Search for E90 bleeding process (cant remember from the top of my head).

[Murphyslaw]

Well the noise is definitely there at idle. I don't know if it is a knocking or not. I have to do a 100mile round trip tomorrow. Been out a couple of times for drives at motorway speeds and it seems fine but I am shitting myself.

Coolant bled and all fine. Oil is all good. Had to liner off the bottom and got a shit load of rocks out but no socket. Should have just took it to the garage

[tmarshall57]

Originally Posted by Murphyslaw

Took it out for a 25min test drive came back and I can here what can only be described as slow drum beat. Very quiet though. Can't hear it when the engine is revved. Now I am super paranoid about what this could be.

Does this noise sound a little like a bass drum or sub woofer beat every half second or so? Does it appear to emanate from the right hand side of the engine (as you face the bonnet)?

If so then I believe the cause is a failing EGR Pressure Converter. You can check whether or not this is the case by compressing or removing the vacuum pipe where it connects to the EGR Valve.

There is more information on this issue in the thread below. Ignore the reference to the "Duck" noise, the drum beat noise is a precursor to the duck squawk noise in my experience.

http://www.e90post.com/forums/showthread.php?t=842393

[Murphyslaw]

Mate you absolute diamond!!!!
Sounds exactly like you describe. Sounds like a right biatch to fix as well. Will give it a test later.
Is it safe to drive with this problem? Will removing or crimping the hose cause any issues?

[tmarshall57]

Just remove or crimp the hose to check that the noise stops - then at least you know the cause.

Then just uncrimp/replace the hose connection. The faulty pressure converter is not a major/urgent issue. The car will be fine to drive. I would never have traced the issue based on the "drum" type noise but the "duck" type noise was a bit more annoying. I had the drum type noise for over a year before I replaced the pressure converter. Depending on how many miles your car has done and the presence of any glow plug related codes or leakage of diesel from the swirl flap housings in the manifold, you may want to include a number of other maintenance tasks at the time the manifold is removed. I replaced the vacuum pipes when I replaced the Pressure Converter.

I did obtain improved MPG and smoother power delivery after replacement so it was a worthwhile job.

[Murphyslaw]

Well just confirmed it.
Crimping the pipe coming out of the egr and the noise goes away instantly!
Massive thanks to tmarshall for pointing me in the right direction.

[makkan00]

Originally Posted by Murphyslaw

Massive thanks to tmarshall for pointing me in the right direction.

+1
Always good to know. Thanks tmarshall.

[tmarshall57]

No problem. Actually it was Dr Dave's post from some months ago relating to the "Duck squawk" that led me to diagnose the EGR "drum beat" noise. These forums are invaluable in helping us all reduce the cost of ownership of some very complex vehicles.