[outrider02]

Hello everyone. I've been lurking on this site since I bought my car 2 years ago, and with enough searching, I've always found the answer to my question without having to create a post. Unfortunately my luck has come to an end.

My car has developed a sort of knocking sound, it sounds like it's coming from the top of the engine.

It started gradually, I didn't really pay much attention to it at first, it's getting colder here in Michigan and I thought it was the normal cold diesel sound. The noise gets much quieter once the engine is warm too. It's gotten more pronounce over the last tank or two of fuel (after which I've stopped driving the car as to not hurt it). It's not the vacuum pump, I removed it and the sound is still there.

My hope is it's an injector at this point. My car is stock other then an EGR delete (but the EGR valve is still connected under the hood). Oil is where it should be, CBU was removed after the EGR delete was installed. I did get a check engine light for #5 glow plug around the same time I started noticing the noise. I've seen no other new codes show up other then that.

The car 220k miles on it, and I was hoping to get another opinion on what the noise might be before I started spending a bunch of money on it.

Thank you!

[Cruiser124]

Wouldn't be a bad idea to remove your serpentine belt to help rule out any of those component. Ac belt is kinda tricky but you can easily remove just the serpentine belt and start the car. See if the noise changes

[Yozh]

Yeah I would start with ruling out your belt drive components. Or even a harmonic balancer. Some worn balancers sound quite bad and resemble a rod knock.

[Monroe]

I have driven my 335d for eleven years, but only recently removed the oil filler cap
while the engine was running.

Surprise! What's that loud click?

[outrider02]

Monroe, not sure what you're telling me, but I can try removing the cap while it's running tonight as well. I'm not sure if anyone notices in the video, but I busted the dang thing taking it off to remove the dust cover. I think it was just old and brittle, hopefully I can find a replacement on eBay or something.

I'll pull the belt off tonight. I know I should've done that before posting, it just looked like a bit of work and the noise seems to be coming from top of the engine.

Will removing the belt making a failing dampener quiet down? I think the answer is yes but haven't found a post that specifically says that yet. I've been reading all morning, another thing I'm going to check tonight is the injector adaptations, and see if they're all similar-ish.

[335dlci]

Stop removing the oil cap. It doesnt prove a single thing.

[BB_cuda]

I had noticed the big hole in your oil cap too. Agree with 335dlci. good luck with finding the noise.

[outrider02]

I haven't gotten the belts off yet, I ordered the tool for doing it though. I might try and tackle it with a stubby flathead screwdriver later today like I read in the post on the forum. My AC belt is looking a little weather-checked, so I may just cut it off anyways and order a new one.

The harmonic balancer doesn't look that bad, at least not as bad as some of the pictures I've seen. Not going to trust that though, I'll still take the belts off.

I got ISTA+ up and running, and was able to scan the car for any faults. The #5 glowplug fault as noted earlier was the only thing out of the ordinary (I also have active EGR faults from deleting it, and some headlight faults from when I hit a deer last winter that were never cleared after it was fixed).

I looked all over for the zero quantity adaptation values to see if there was one particular injector way off from the others. I could find the area where you can reset it, but I couldn't find a way to read the current values. Can anyone point me where to look for those?

Thank you for all your help again!

[TheMidnightNarwhal]

Originally Posted by 335dlci

Stop removing the oil cap. It doesn't prove a single thing.

No what he's saying is that there is literally cracked holes in OP's oil cap lol. And that might be from where the sound is coming out of.

[outrider02]

Oh I see what you mean. Ya I cracked that taking the dust cover off while trying to diagnose this noise. It was definitely making the noise before I did that.

It was stuck on really good, so I tried using a pair of pliers to open it and it cracked. I'll replace it, assuming the knocking sound doesn't end with me needing a new engine...

[Owen81]

Definitely could be the noise coming through the cracked cap if it opens up the valve train to atmosphere, not to mention that probably isn't good for the CCV system to work as designed.

[outrider02]

The cap wasn't cracked when I started. The knocking sound came first, I parked the car, and had guessed it was the vacuum pump, cap was NOT cracked at this point. When I went to pull the dust cover off the top of the engine, I busted the oil cap. Vacuum pump is also removed in the video, I haven't done anything but start it a couple times to see if the noise went away.

It's hard to tell, but it sounds like it's coming from the top and middle, like cylinder 3 or 4 area.

Is there any reason I couldn't disconnect injectors one cylinder at a time, and see which hole the noise is coming from? I mean on spark ignited engine that's basically what we'd do. Or is there a way in ISTA or one of the other tools to shut off a cylinder?

[Owen81]

I would pull the belts, then the HB and if the noise is still there its probably an internal issue and you should find a new engine.
Injectors make ticking noises, this sounds more like a thumping, just my opinion however. Please let us know what you find.

[TheMidnightNarwhal]

Originally Posted by outrider02

Oh I see what you mean. Ya I cracked that taking the dust cover off while trying to diagnose this noise. It was definitely making the noise before I did that.

It was stuck on really good, so I tried using a pair of pliers to open it and it cracked. I'll replace it, assuming the knocking sound doesn't end with me needing a new engine...

Ohh gotcha ok, I thought for sure you didn't notice haha.

[outrider02]

Don't mean to just post for the fun of posting, but I'm feeling a lot better. I cut the AC belt, tool won't be here until Tuesday and the old one looks shot anyways, so I'll just order a replacement. I pulled the main accessory belt as well, and the noise is substantially quieter. I hope this means it's the dampener. Still a few hundred bucks, I'll probably just replace with the fluidyne one, but that's easier then pulling an engine.

I'm writing this from the shop laptop. I'll pull the dampener next, and with any luck my next post will be a huge thank you!

[outrider02]

Ok well I think this is good news. I pulled the balancer off and there's really no knock now. There's very faint once-per-rev tapping sound, but I don't think it's anything I need to worry about. I did try putting the car in gear and giving it a little pedal to see if the noise got louder under load, and it stayed the same. So it's probably just normal diesel noises. I uploaded another video if anyone has a comment.

I should've done a video when the pulley was still on but with no belts, as I'm a little concerned the noise might have actually been coming from one of the accessories. I turned them each with my hands and nothing felt wrong. The balancer really looks ok, but I know they're prone to failure. For what it's worth, the car is quieter now then any other time since I've owned it.

So for repair, I'm leaning towards just getting the Fluidamper unit. Any reason I shouldn't?

[BB_cuda]

I like my Fluidamper. Go get the complete kit with clutched alt pulley, new belts, and new screws for the damper.

[Shmee]

Just for future reference, I just did my belts and I didn't use a tool (I'm too cheap). To get the ac belt on I just put a 10mm on one of the 4 bolts on the balancer and cranked it a little clockwise and the belt managed to get itself on.

[outrider02]

Reviving my old thread just in case anyone finds this and has a sound similar to mine. Changing the dampener seemed to help, but it didn't go away completely. I finally found the time to drop the subframe and remove the oil pan.

My #1 main bearing cap has only a tiny piece of bearing left in it. The crankshaft and main cap is scored, so with any luck I'll be able to machine my block and crank and use oversized bearings.

If anyone wants to make a good deal on a short block let me know LOL!

[POBEP]

Originally Posted by outrider02

Reviving my old thread just in case anyone finds this and has a sound similar to mine. Changing the dampener seemed to help, but it didn't go away completely. I finally found the time to drop the subframe and remove the oil pan.

My #1 main bearing cap has only a tiny piece of bearing left in it. The crankshaft and main cap is scored, so with any luck I'll be able to machine my block and crank and use oversized bearings.

If anyone wants to make a good deal on a short block let me know LOL!

Sorry to hear about the bearing cap.
I have a similar noise, but considerably higher pitch, more of clapping sound (rather then knock).

I drove 20K miles since I noticed it.
It surfaces on occasion (prominent on idle, completely goes away with 2k+ rpm)
Stethoscope points to the #1 injector