Help Identify this noise - Timing chain?

[ErnieThe02]

OK - as I’m sorting out my new rig, I’ve noticed a clattering noise that starts right around 3,000 RPMs.

Based on the location I’m assuming it’s timing chain or chain guide related but was hoping to get an expert’s view.

Any help appreciated…new to BMW 2002s

 

 

[Stevenc22]

Is your fan hitting the alternator pulley bolt? If you have an aftermarket alternator, the fan doesn't quite clear the alternator and makes a hitting noise.

[ErnieThe02]

12 minutes ago, Stevenc22 said:

Is your fan hitting the alternator pulley bolt? If you have an aftermarket alternator, the fan doesn't quite clear the alternator and makes a hitting noise.

Looks like the fan has plenty of clearance.

It sounds chain like and only happens at or above 3,000 RPM

[jgerock]

1 hour ago, ErnieThe02 said:

Looks like the fan has plenty of clearance.

It sounds chain like and only happens at or above 3,000 RPM

If you cannot change the fan belt without cursing out loud due to the tight clearance, you have a problem!  This happens to many cars that have been hit in the front and not properly fixed.  Remove the radiator and use a dead blow hammer on the edges where the radiator mounts to the nose. It helps a great deal after this.  Been there, done that.

 

Also, you can remove the chain tensioner, clean it and reinstall and bleed it to reduce timing chain noises.

[Son of Marty]

I'd pull the valve cover and see how slack the chain is and if the upper sprocket is warn then you can see if the tensioner is fully bleed. Have you set the valves yet?

[ErnieThe02]

Thanks guys.

I checked fan clearance on the bottom and plenty of room.

Based on the noise I think the chain tensioner sounds like a very likely culprit.

No doubt there are some worn tips on my fan and assume it rubbed on something in the past but there are no fresh abrasion marks on the radiator, alternator pulley etc.

 

I will start researching the timing chain tensioner…..if anyone happens to know the BEST thread on this please let me know.   Never heard of bleeding a tensioner in my life so this should be an adventure.

Really appreciate all the advice thus far

 

[ray_]

Pull the fan belt and see if the noise disappears.

 

What @jgerock said.

 

 

[tech71]

19 hours ago, ErnieThe02 said:

No doubt there are some worn tips on my fan and assume it rubbed on something in the past but there are no fresh abrasion marks on the radiator, alternator pulley etc.

Wow that fan looks super super close to your radiator, you sure nothings going on there?

The fans an airfoil producing lift/thrust like any other airfoil, as RPM increase so do the forces of centrifugal and aredynamic bending. Simply put, its going to change shape a little at higher RPMs, maybe enough to contact something.

Your crank pulley looks very 320i/E21 ish. I think E21/E30 water pumps stick out more.

Is that a 1.8L (later) M10 engine stuck in there?

Can you pan back a little a take some more pics? from the top

Edited May 29, 2023 by tech71

[ErnieThe02]

Thanks guys.

I’ll check by pulling the fan belt tomorrow.   Before I pull the belt I might put some blue painters tape on the top and bottom lip pf the radiator (closest contact point to fan).   I’ll run it up to 3k and if the tape is scratched/scuffed…..

Here are a couple more photos if that helps.
Really appreciate all the advice thus far

 

Edited May 29, 2023 by ErnieThe02

[ErnieThe02]

38 minutes ago, tech71 said:

Wow that fan looks super super close to your radiator, you sure nothings going on there?

The fans an airfoil producing lift/thrust like any other airfoil, as RPM increase so do the forces of centrifugal and aredynamic bending. Simply put, its going to change shape a little at higher RPMs, maybe enough to contact something.

Your crank pulley looks very 320i/E21 ish. I think E21/E30 water pumps stick out more.

Is that a 1.8L (later) M10 engine stuck there?

Can you pan back a little a take some more pics? from the top

And as far as I know its an all stock rig but I’m at least the third owner and just getting acclimated to 02s

[Mike Self]

In this picture...it appears that the fan belt between the water pump and alternator pulleys isn't properly aligned.  While it may not be causing your noise, it's gonna cause problems with the belt and the bearings in either the water pump or the alternator (or both) eventually.  Hard to tell which is the cause--water pump pulley or alternator.  

 

When you check your timing chain sprocket for wear, look at the tops of the sprocket teeth.  There should be a narrow flat space atop each sprocket tooth.  If the teeth come to a point, that's probably the source of your noise--and you're ready for two new sprockets, a chain and probably guide rails...

 

mike

[jgerock]

4 hours ago, Mike Self said:

In this picture...it appears that the fan belt between the water pump and alternator pulleys isn't properly aligned.  While it may not be causing your noise, it's gonna cause problems with the belt and the bearings in either the water pump or the alternator (or both) eventually.  Hard to tell which is the cause--water pump pulley or alternator.  

 

When you check your timing chain sprocket for wear, look at the tops of the sprocket teeth.  There should be a narrow flat space atop each sprocket tooth.  If the teeth come to a point, that's probably the source of your noise--and you're ready for two new sprockets, a chain and probably guide rails...

 

mike

Alrighty then!  Mike points out another possible problem. The fan may have been installed backwards.  The fan hub has two different offsets. The deeper side should face the water pump pulley.  This happened to me. You’ll have to remove the radiator to flip the fan over.

[jgerock]

For comparison purposes, here’s my 73tii. Note the fan and water pump pulley distance.

[jgerock]

Back to the main topic…

I found 57 results searching for “bleeding the timing chain tensioner”

Heres one of the results.

 

[ErnieThe02]

Awesome info all around.

@jgerock- that photo is incredibly helpful and @Mike Self, makes sense on the fan being backwards.   I couldnt figure out why there were wear marks on the back side of it but assume it was rubbi g on something in the past and they decided to flip it.   
 

thanks for the links on timing and tensioner.    It’s gonna take some time for me to tackle all this as my day job will start getting in the way 😀