Another knock thread

Hi there!
First of all, this's my first post here. I've been reading since I bought my 04 mkiv AGR engine, a year ago.


I know it's a bit tricky to diagnose a knock sound over here, but I'm getting frustrated. A few months ago, I started to hear a knock, mostly when cold. I took it to a mechanic and he told me it was an injection problem; so he had the injectors cleaned with ultrasound and calibrated, and he also changed the lifters and told me the camshaft was ok.
Now, when winter started here in the south, the knock came back more audible. Then I took it to another mechanic, who told me also it was the injectors. He scanned it, and there were no fault codes, the timing was ok, injectors on channel 13 were with less than 0.6 difference. He told me not to worry and drive it like that

Another data, the DMF was changed about 20k km ago, alternator pulley changed like 1000km ago, I'm using 5w40 motul 8100 oil, changed last week; the car has 206k km. I've been hearing the knocking for the last 6k km. The first times I would only hear it when the engine was cold, but now I get to hear it with the engine warm.


Should I rebuild the injectors? They were only cleaned and calibrated.


Here's a video, do you hear something unusuall?


https://www.youtube.com/watch?v=HXxVLRAAHlk

oh good lord
what mechanic is this? im worried
there are bad lifters out there (knock off stuff) and putting new lifters with a old cam is not ideal, especially if you dont run some zink in there to brake in the lifters! and cleaning and calibrating TDI nozzles is NOT something that a DIY or a simple mechanic with a $80 ultrasonic cleaner from amazon can do. in fact your not supposed to clean the injectors this way. Pop testing and calibrating? WHY once they have been set up correctly they usually last a long time unless you run with no filter!
that really sounds like a valve to me, but with TDI's that sound can come from a few places.
does it go away as soon as the rpms increase? if so, its a oil pressure related issue like the lifters, if it takes a while to go away, say at like 2000 rpm,s and it clears up it could be the injection related issue. its hard to tell, best way to tell where its coming from is with a mechanics stethoscope, start poking around, if it comes from the IP or a injector, you WILL CLEARLY hear it isolated from that. try at the head and at the injector body. im not saying its any of these with any certainty, but there are places you can start.

run some molly purge in an isolated loop and if it clears up at all, then its fuel/ injection related, if it does not, then it could still be the IP and its possible it could be really bad. BUT you can find that out though VCDS and some other signs.
SO moving to the oil system like lifters and such, get an oil PSI gauge.
if when warm your oil pressure drops below say 12psi your lifters could be fubar, not so much the lifter but the bore it rides in is worn out, letting excess oil though and not stiffening the hydraulic part of it to take up slack on the cam.
Why did the mechanic replace them and with what part number and from whom did he get them from? replacing the lifters if the faces are in good shape is pointless as its not the root of the issue.

anyways, im not a guru in this topic but i have had to deal with a very similar issue with my AHU and its the lifters and im pushing 8psi blowing past them! good thing she is getting rebuilt.

also dont DIY your nozzles, IMO tyou should send them out to kerma or darkside for a hotswap on nozzles and pop testing. there are in fact only a hand full of tuners/ performance shops that can do this with calibrations that is worth paying for.
pop testing is not as simple as you think, there are many stages that it is done at.

is your mechanic a trusted TDI mechanic or just some rando shop?

Welcome mauricio!
A lot of echo in that parking garage. Not ideal for listening.
It sounds basically normal to me, a little slappy though.
Do you have any "tuning mods", chip tune?
Is EGR delete your only mod?

Mongler's right, it's dumb to replace just the lifters and not the cam as well. I would start there. Make damn sure the lifters are INA branded.

injectors on channel 13 were with less than 0.6 difference
I doubt it's the injectors. I lean towards cam. It's not hard to inspect it yourself!

Sounds normal to me, but you know your car. Since you can reproduce at idle, get in there with a stethoscope (I use a hose in ear) and probe everywhere, it should be obvious where it is loudest. But mine have always had a clatter (or knock?).

A leaky EGR pipe could cause a knock.

Does not sound right to me, not like my BEW which is basically an AGR if I’m not mistaken. The background noise is right but I hear a clear slap or crack at engine frequency which I don’t expect. I can’t be of much more help but I second Bob, find out where it seems to be coming from.

AGR is closer to ALH than BEW.

I had a customers car making that exact sound right before it exploded a lifter and dropped an exhaust valve . i feel bad i didnt investigate it further at the time

Hi! Thanks for your replies!


@Mongler98 when the mechanic said the injectors were cleaned and calibrated he referred he sent them to a shop to had them cleaned with ultrasound and then poptested, he didn't do it himself. For the lifters, he said they were not holding the oil; and the replacement were germany made Ina lifters, I bought them myself.

The sound quiets past de 2500 rpm range, but in a way I dont feel very comfortable pushing it hard, it's like I feel the engine is unbalanced, so when going on the highway I tend to drive it not much more than 3000 rpm. And also the sound when the engine is hot is more like a scrap and not like a knock
Here's the pic of the cam the mechanic sent me when he changed the lifters, I know it's hard to tell from a picture (i have a few more), but, does it look bad?








Sorry about the first video, here's another one on the street on a cold start https://youtu.be/4jCCtmXL-NU

Unluckily there are no trusted TDI mechanics around here, so I have to take it to anyone who accepts diesel engine cars, and sadly there are only a few, tomorrow I'll try to take it to another one who has good reputation, at least with lightweight turbodiesel trucks. My aim was to get someone to make a compression test, should I do this?


As for the oil pressure test can I do it myself?


Again, thank you!

Pic didn't come through.

That was a really sluggish start in the video. My golf starts almost instantly.

Maybe post a video after the car is warmed up so we can hear how the sound changes?

Bengoshi2000 said:

Pic didn't come through.

That was a really sluggish start in the video. My golf starts almost instantly.

Maybe post a video after the car is warmed up so we can hear how the sound changes?

Click to expand...

Yeah, cold starts are usually like that, sometimes it improves when I do a double wait for the glow plugs to heat a bit more (previous owner addapted a generic glow plug module) :/


I uploaded the pic to imgur, now I uploaded to the forum gallery, can you see it now?

That pic is still too small at full-size to evaluate the cam.
Have a look at the tip of the lobe in this pic:
http://pics.tdiclub.com/data/500/P1020531.JPG
Sometimes you can't see damage until you get very close.
EDIT: If it were me, I would pop that valve cover off and inspect the cam myself.

STDOUBT said:

That pic is still too small at full-size to evaluate the cam.
Have a look at the tip of the lobe in this pic:
http://pics.tdiclub.com/data/500/P1020531.JPG
Sometimes you can't see damage until you get very close.
EDIT: If it were me, I would pop that valve cover off and inspect the cam myself.

Click to expand...

Yeah, the pic was sent via whatsapp, sorry about that

Today I tried to remove the valve cover but the mechanic who changed the lifters rounded two of the allen bolts, and also overtightened all of them
I don't know what to do with those bolts.

He broke more things than the things he really fixed. (he also broke the steering fluid reservoir)

That happened to me too. That's why nobody touches my cars but me now.
If I can help it!
I had to get a bolt-out 10mm, tap it onto the head of the stripped nut, and out it came.
Something like this for 3/8" drive wrench.
EDIT: replacement bolts should be "M6 x 25mm"

STDOUBT said:

That happened to me too. That's why nobody touches my cars but me now.
If I can help it!
I had to get a bolt-out 10mm, tap it onto the head of the stripped nut, and out it came.
Something like this for 3/8" drive wrench.
EDIT: replacement bolts should be "M6 x 25mm"

Click to expand...

Well, I know other people that have touched it too
Something else you can try is vice grips on the valve cover bolts, as long as they are the ones on the front of the engine. If they're next to the intake, you're going to need an extractor of some sort to get a good grip on it.

Nero Morg said:

Well, I know other people that have touched it too
Something else you can try is vice grips on the valve cover bolts, as long as they are the ones on the front of the engine. If they're next to the intake, you're going to need an extractor of some sort to get a good grip on it.

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Yeah, but I was keeping an eye on things !

By the way mauricio,
The torque value for the valve cover nuts is 7 Ft. Lbs -or- 9 Nm.
Or just "Pretty snug". And they should have non-locking washers on them.

Hi guys, sorry I haven't posted in a while. I still can't get out those two bolts of the valve cover; I'm planning to use one of those conic shaped left threaded extractors, I hope they work. In the meantime I sent the injectors to a more serious shop, they were pop tested and re calibrated, but the engine still sounds the same, although the startup has improved a little, but still a bit slugish.

Hi! Today I inspected the camshaft, I didn't noticed any substancial wear on the lobes.
The ticking is still there, but I have to reinstall the injectors, as I noticed some leaking.

Still have to chek oil pressure and do a compression test; I'm thinking about droping the oil pan also, but next weekend I have to do some trips with the car.

mauricioezequiel said:

Hi! Today I inspected the camshaft, I didn't noticed any substancial wear on the lobes.
The ticking is still there, but I have to reinstall the injectors, as I noticed some leaking.

Still have to chek oil pressure and do a compression test; I'm thinking about droping the oil pan also, but next weekend I have to do some trips with the car.

Click to expand...

Camshaft looks good to me.

What is the static timing set to? If it's out of whack it will cause a ticking noise. I think too advanced will do that.

jokila said:

What is the static timing set to? If it's out of whack it will cause a ticking noise. I think too advanced will do that.

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The last time I checked it was 57, with some deviations between 53 and 60; always near the blue line.

Reviving this old thread, some months ago I had the injectors checked at a serious shop, one of them was sticking but the shop just cleaned and adjusted them, the tick was noticeable quieter, but now has come back. I think I should do a complete overhaul now.

Did the shop indicate they were dirty?
Did you change the fuel filter?
Check for anything in the tank?

wonneber said:

Did the shop indicate they were dirty?
Did you change the fuel filter?
Check for anything in the tank?

Click to expand...

They only told me two of them were sticking (never told if sticking open or closed)
Didn't replace the fuel filter as it only had 8k km when I serviced the injectors