3.0D (M57N) Tapping/Knocking/Ticking?
 

Hello everyone

I own a 2005 X5 with M57N (3.0D) EURO3 engine, which came without the DPF and swirl flaps from the factory.

I just had the exhaust manifold changed because it was cracked. The shop suggested changing the valve cover gasket as well with new injector washers.

Picked the car up, everything was well. On the same evening, I started the car and heard quite a loud continuous tapping noise from the engine bay. Tapping increased with more revs.

Started it up a few days later and it was running quite rough, the vibrations were felt inside as well. Connected it with INPA and injector values were quite horrible.

https://i.ibb.co/k8yL9Gr/269815320-1...72809029-n.png

Now I don't know how exactly the injector balancing logic works, but I assumed that 4th was overflowing, and5th was brought down to compensate.
I took some correctional reading about a month ago and they were all within tolerances I suppose, the highest positive value was 1.75 (4th cyl).

After seeing the corrections, I figured that the tapping I heard was due to a faulty injector. I found a local shop to quickly try and diagnose the issue (last day of MOT is on 31.12, lucky me). They switched some injectors around and the corrections remained the same.

Once it was kind of clear that it's probably not injector-related, they proceeded to remove the intake, and here's the result:


Smoke is coming out of the 4th cylinder intake. Did the guys who did my exhaust manifold do something wrong while in there? Was something dropped into the intake? **** knows, maybe it's just a coincidence. I truly hope it's not a bent valve.. The shop also removed the valve cover and said that everything looks alright there, no broken rockers/springs.. and said that the next step would be removing the cylinder head in order to understand what's really wrong. The guy said that if there's some kind of build-up and the valves aren't closing/opening properly, it might be possible to clean them without removing the head. I figure that before stripping off the head, it would make sense to find a camera of sorts that would allow examining the valves from inside the cylinder.. I think I heard that something like this exists.

I can't see the video. Seems like too much of a coincidence that this happened virtually right away after the first shop did the VCG. OTOH, it's hard to mess up that job in a way that would cause valvetrain problems! My first guess was going to be that perhaps a fastener or tool got left behind in the cam area, but you said a second shop removed the VC and found nothing apparently wrong. This is a weird one.

This might not be the best forum to post this as BMW didn't sell E53's in the USA with the M57 diesel engine. You might get better response trying one of the E70, E90, or diesel-specific forums where more people have experience with that engine. I happen to have an E70/M57, but I'm new to the diesel so have limited experience/knowledge.

Oh, and on a gasser, you can sometimes take a peek with a borescope down the spark plug hole, but I'm not aware of any way to look into a diesel cylinder unless the injector ports might provide access?

AM.

I fixed the video. Thanks for your response. An easy way to mess up that job would be by letting something fall into the intake port(s) while taking off/reinstalling the intake manifold. I was kind of skeptical of their suggestion in the first place because I know that it's possible to swap the exhaust manifold without taking off the valve cover etc..
But it's possible to get into the cylinder head either through the injector port or the glow plug port, but I'm not sure what kind of an endoscope it should be that would allow examining the upper part of the cylinder where the valves are..

Unfortunately looks like damaged intake valve on cylinder Nr.4. Loss of compression also explains the high positive correctional value on that cylinder. More than likely this has something to do with previous repair.

Think so as well. Do you know if getting the endoscope down the intake port will show anything?

It might not show anything obvious because even a minor dent can cause this kind of leak. If the exhaust is coming out of intake port like in your case the head has to come off anyways.

Update time. The shop proceeded with removing the head. Called today and told me to say thanks to the guys who took off my intake manifold to replace the exhaust manifold..

Well, shit.

https://i.ibb.co/2F0HkCG/IMG-20220106-WA0003.jpg
https://i.ibb.co/db812Zw/IMG-20220106-WA0006.jpg
https://i.ibb.co/tHrWwMZ/IMG-20220106-WA0005.jpg
https://i.ibb.co/NZhg5zm/IMG-20220106-WA0007.jpg

So what kind of damage was found and any guesses what caused it?

Sorry, I just realized that the pictures weren't showing at first. Check my message again.. some sort of small metallic piece, 3-5mm. No idea what it could be. My intake came without the swirls as well, so the current theory is that they dropped something into the intake when it was off..

Check if the valve plate on EGR valve is still intact. If it's OK then it must be something the previous shop dropped in intake duct or left inside intake manifold.