[repete]

Hi all,

I’ve got a 2011 335d that’s been tuned (and all that other good stuff) and I’m hearing a very loud ticking coming from what seems to be the top end.

A bit of history, I did CBU cleaning, replaced vacuum lines, put in a downpipe and exhaust and got a tune. After this, the car drove fine for a while but developed an intermittent misfire.

I found the misfire to be due to the cyl 6 injector, which I replaced with a Bosch reman part and reprogrammed injector correction value using ISTA. This is when the tick started - however it does not seem to be due to the injector, it has been driven 150 miles or so since replaced and the tick still sounds just as loud as before. I unplugged the cyl 6 injector while running to see if it was the cause of the noise, but it was not!

https://youtube.com/shorts/sSlMrJsce...ObUY2czBb1G-pX

This video shows the sound, its frequency is at half of engine rpm which leads me to believe it’s something on the top end. So far I’ve pulled the belts - no change, pulled the valve cover - no obvious damage or issues or sounds when turning over, pulled the vacuum pump - and noticed some pretty severe looking wear (images attached). (edit: crank vibration damper was also replaced, so I doubt it is the cause)

The car has 167k miles, so I’d understand some wear but this seems a bit extreme. Could this have been causing the tick? Could it perhaps be a failed lifter, should I pull the cams to see? Oil looks okay, I don’t see any evidence of bearing failure on the bottom end but it may be worth getting an oil analysis done to be sure.

Anyone else had a tick like this? I tried to include all relevant information but most likely left some out so feel free to ask any clarifying questions.

Thanks!

[lnxguy]

You'd find it pretty easily with a stethoscope. Sounds like an injector to me. Stop ripping apart the engine before you're sure.

[repete]

Originally Posted by lnxguy

Stop ripping apart the engine before you're sure.

Haha oops, you’re probably right.

Since I already had the valve cover off though, I turned the engine over with the starter to build oil pressure and didn’t notice any of the lifters making noise, they were all firm and not spongy at all.

I figure with the vacuum pump being so worn internally it’s probably just a good idea to replace it.

I suppose I’ll get it all back together once the vac pump and gaskets arrive, and check with a stethoscope to narrow it down.

I also hate to admit it, but I made a boneheaded mistake last time I pulled the injectors out and one injector ended up being installed with 1 crush washer on it and the old washer still stuck in the head, I wonder if it was leaking or if being offset screwed up the injection pattern making it knock. Lesson learned, I will report back when I have more info!

[krashDH]

Originally Posted by repete

Haha oops, you’re probably right.

Since I already had the valve cover off though, I turned the engine over with the starter to build oil pressure and didn’t notice any of the lifters making noise, they were all firm and not spongy at all.

I figure with the vacuum pump being so worn internally it’s probably just a good idea to replace it.

I suppose I’ll get it all back together once the vac pump and gaskets arrive, and check with a stethoscope to narrow it down.

I also hate to admit it, but I made a boneheaded mistake last time I pulled the injectors out and one injector ended up being installed with 1 crush washer on it and the old washer still stuck in the head, I wonder if it was leaking or if being offset screwed up the injection pattern making it knock. Lesson learned, I will report back when I have more info!

Regardless, that vac pump is toast. Nothing should be rubbing like that and could very well be the noise. It's basically hollow so anything that is metal on metal will resonate. I just had mine apart as well and no internal wear like that.

[repete]

Krash, I agree, no clue what caused it to wear so badly but it will definitely be replaced. I’m hoping that plus the correctly installed injector seals will fix it, thanks for the info!

[lnxguy]

Originally Posted by repete

Krash, I agree, no clue what caused it to wear so badly but it will definitely be replaced. I’m hoping that plus the correctly installed injector seals will fix it, thanks for the info!

My vac pump looked similar when I pulled it apart, it's really not abnormal.. They wear out just like any other part. Hopefully the vac pump is the fix!

[Tambohamilton]

Following this for the fix...

[335dlci]

Lifters do fail

[barf]

It's very common for the vacuum pump to wear and make a ticking sound on the M57.
But that's not the noise of a bad vacuum pump on the video. It's more of a fast ticking sound than knocking with the vacuum pump.

Did you fit a new injector? It might be due to bad injector but in case its not I would check this:
Although it' quite hard for me to tell from the sound in a video, it seems like you might have exhaust gases blowing back into intake manifold. Remove the intake manifold and run the engine(MAF unplugged) and see if there is smoke coming out of intake ports.
In any case speaking from experience the sound is caused by something wrong with a cylinder for sure. That is not a sound of a bad lifter but something with combustion.

It's quite common with a hard tune and bad injectors that on the M57 3.5d you melt the pistons. And usually for some reason it's the 6th cylinder that goes bad from experience.

I have heard this sound before on M57 and it has always been something not great (once a piston was knocking from the rod/piston seat, once it was bent valves) but of course it's impossible to tell 100% what it is.

EDIT: I've had problems with a bosch remanufactured injector before, sometimes they require a bit of driving to work properly (a little bit of hard driving) and one injector was bad from the start but that was a solenoid injector not piezo.
If you still have the old injector you can try fitting that and if noise goes away you will know it's due to bad injector. Or find another used injector.

[Servord]

I’m having a similar issue on my 2011 35D. Did you replace the vacuum pump or do something else to resolve the ticking?

[krashDH]

Originally Posted by barf

It's very common for the vacuum pump to wear and make a ticking sound on the M57.
But that's not the noise of a bad vacuum pump on the video. It's more of a fast ticking sound than knocking with the vacuum pump.

Did you fit a new injector? It might be due to bad injector but in case its not I would check this:
Although it' quite hard for me to tell from the sound in a video, it seems like you might have exhaust gases blowing back into intake manifold. Remove the intake manifold and run the engine(MAF unplugged) and see if there is smoke coming out of intake ports.
In any case speaking from experience the sound is caused by something wrong with a cylinder for sure. That is not a sound of a bad lifter but something with combustion.

It's quite common with a hard tune and bad injectors that on the M57 3.5d you melt the pistons. And usually for some reason it's the 6th cylinder that goes bad from experience.

I have heard this sound before on M57 and it has always been something not great (once a piston was knocking from the rod/piston seat, once it was bent valves) but of course it's impossible to tell 100% what it is.

EDIT: I've had problems with a bosch remanufactured injector before, sometimes they require a bit of driving to work properly (a little bit of hard driving) and one injector was bad from the start but that was a solenoid injector not piezo.
If you still have the old injector you can try fitting that and if noise goes away you will know it's due to bad injector. Or find another used injector.

It's also hard to define what's "bad" to people over the internet. These cars, and all other diesel cars, have a distinctive "tick" due to the combustion differences between gassers. My TDI had a different tick sound than this one does (BMW's is actually much quieter even with more cylinders).

That being said, ticking is also a characteristic with diesels from the injectors. But depending on the severity is hard to tell over the internet, even if you were to watch a video.

[335dlci]

Lifters do get old in these engines and cause more ticking than normal.

[repete]

Quick update, been busy with other projects and school.

In the process of removing the valve cover, my dumbass removed the two screws to the vacuum pump half moon that BMW says NOT to remove. Definitely a RTFM moment.

One broke above the head and can be extracted, the other broke within the head and is…to put it simply, screwed. I tried drilling & using extractors, no luck, tried hammering a torx bit in, and it broke inside the screw

So I now have a piece of incredibly hard steel in my way. I tried welding to it but wasn’t able to do much as I was afraid of melting the head, overheating and altering the microstructure, or just plain warping it.

I also tried using 70% nitric acid which is supposed to be able to dissolve the steel screw, but the aluminum head should be protected by its oxide layer. After about 2-3 weeks of filling & replenishing the hole with acid, I’ve seen almost no progress.

My options at this point are to get an EDM capable shop to try to extract it (which I’d have to remove the head for), or just replace the head entirely—unless anyone else has suggestions.

Let this be a lesson (a very stupid one at that) to RTFM before any seemingly simple procedure and don’t remove those screws, whatever you do!!!

Anyone got advice (or a head for sale)? I may have had to end up removing it anyways if I burnt a hole through a piston, so consider it an exploratory surgery. Don’t be an idiot like me.

Update to the update: found a head on ebay for $220 with cams, valves, and lifters included. Gonna order head gasket and other ancillary parts, will thoroughly inspect new head for warping or cracks. Will update soon

[lnxguy]

Yikes, that got expensive in a hurry.

[repete]

Originally Posted by lnxguy

Yikes, that got expensive in a hurry.

What an understatement!

Got the head pulled off today. Dear God save my soul (and my wallet).

See attached images: piston has something embedded in it (not sure if it’s a piece of the piston, or something else. Clearly did damage to the head as well. Cylinder wall fortunately looks okay.

Does this look like damage anyone’s seen before? I honestly have no idea if that was a molten piece of piston, or something else.

Anyways, ordering a new piston now…got some fun work ahead of me. Pray for my wallet! I’m very glad I pulled the head.

[Tambohamilton]

Well, that's new! What is it? Looks hard, like it hasnt deformed much and just been hammered directly into the piston/head.

Any damage on the injector or anything else?

[Scubudo]

I can't say for sure, but the only explanation I can fathom, is that something fell in while you were changing the injector.

[repete]

I looked a little closer and I realized I’m such a dummy

Turns out when I was replacing #6 injector, I had snapped off the very top e-torx part of the valve cover bolts, and well, it fell into the intake or injector port. Yikes. I could never find it at the time and now I know!

Closer up images confirm that yes, that is indeed what it is. Very yikes. I’m very fortunate the damage wasn’t worse.

Injector and glow plug are both okay, I think I’ll get away with just replacing the affected piston and the head.

[Tambohamilton]

Thought it looked like etorx

Fingers crossed you get away with just the obvious parts...

[335dlci]

Yikes.