Grinding noise just off idle (video inside)

[cobra]

My car is making this noise just off idle. It's a grinding noise that I can hear and feel - feels like it's coming from the front/vanos area. I have all the VANOS fixes installed.

- Only audible coming off idle, goes away at ~1100RPM
- Not heard at idle
- Not heard at any engine speed higher than ~1100RPM
- No codes or issues, engine runs smooth

I have tried searching online and found other videos that exhibit the same noise.


This video at 0:10

https://www.youtube.com/watch?v=lzvFWu-_hsI

Kinda similar noise to this, but mine is not present at idle like his.

https://www.youtube.com/watch?v=kJ2fmWhPbBo

[cobra]

It appears this guy has the same sound, but is present at idle.

https://www.youtube.com/watch?v=8ZfqTsVZV1g

[sapote]

Remove all belts and see if it changes.

[cobra]

I don't think it's the belts. I have all new pulleys and it really sounds like it's coming from the vanos/cams. I will give it a shot anyway.

Anyone else?

I would appreciate if anyone could share videos of their engines:
-Fully warmed up
-Gently modulate throttle to move between 800 and 1200RPM.
-Video at vanos unit

[Shonky]

Use a broom handle or similar (timber is probably best), ear on on the side or end and the other end on various parts of the engine? Might give you a better idea of where it's coming from. You'll be surprised how much more you hear. Or a proper automotive stethoscope if you happen to have access to one.

Timing chain related? It clearly does it as you rev it slightly.

[cobra]

I used a screwdriver and it sounds like it's coming from the exhaust side of the vanos.

[maupineda]

A couple of thoughts…

broken exhaust hub tab
broken chain guide
bad chain tensioner
loose cam gear bolts

to be honest, I would open her up to check some, if not all, of the above

i do agree it sounds like is coming from the VANOS

i know you said you have all fixes, but sometimes things fail prematurely or maybe an assembly issue/miss left something loose.

[sapote]

A couple of thoughts…

broken exhaust hub tab
broken chain guide
bad chain tensioner
loose cam gear bolts

to be honest, I would open her up to check some, if not all, of the above

i do agree it sounds like is coming from the VANOS

i know you said you have all fixes, but sometimes things fail prematurely or maybe an assembly issue/miss left something loose.

All of these are good candidates, but why the noise only happened at the beginning of increasing from idle.

[cobra]

A couple of thoughts…

broken exhaust hub tab
broken chain guide
bad chain tensioner
loose cam gear bolts

to be honest, I would open her up to check some, if not all, of the above

i do agree it sounds like is coming from the VANOS

i know you said you have all fixes, but sometimes things fail prematurely or maybe an assembly issue/miss left something loose.

So I just did the chain guide and the hub was intact 3 days ago when I did work on it.

The tensioner is a possible candidate. Could it be that when revving up initially, the chain is able to slap but as soon as oil pressure builds up more it keeps it tight?

I also replaced the vanos line, and wondered if there is an accumulator purging process required for that?

[maupineda]

All of these are good candidates, but why the noise only happened at the beginning of increasing from idle.

Could be the tensioner as it builds up pressure when idle rises

[cobra]

Could be the tensioner as it builds up pressure when idle rises

Anyone know how I test the tensioner? Would be nice if this is all it was.

[jet_dogg]

How many miles and when was the last time you changed it?

[cobra]

How many miles and when was the last time you changed it?

100k miles now. I have never changed the tensioner, only the actual plastic guide. I just replaced that over the weekend.

[ZiMMie]

Anyone know how I test the tensioner? Would be nice if this is all it was.

Remove the belts as suggested earlier in the thread.

[cobra]

Remove the belts as suggested earlier in the thread.

I'm talkin about the timing chain tensioner not the belt tensioner.