Groaning noise after TB change

[Aleman]

Hey E30 hive mind -
Have you ever experienced a loud groaning noise coming from your running M20 engine following a timing belt change?
The noise was not there before the TB change, and it starts immediately when the engine starts.
It keeps making the noise even after reaching operating temp.
I suspect a faulty (new) belt tensioner, but I can't get my mechanic's stethoscope in there to confirm it. I did confirm it's not the alternator.
Any way I could confirm the tensioner w/o taking everything apart and basically re-doing the TB job?
TIA

[MrBurgundy]

post a vid

maybe PS fluid is low

har har har

[Aleman]

Low PS fluid groan would be a good description of how it sounds. None has leaked that I'm aware of, but I'll double check anyway - good suggestion. I have to wait till the Philly weather moves out of frozen tundra Hoth mode before heading back out to the garage to make a vid.

[MrBurgundy]

I think the reservoir has an integrated filter as well. Maybe a combination of freezing temps, slightly dirty filter and slightly low fluid is making that pump choke a bit

[uturn]

Just remove the power steering belt.

[roguetoaster]

Just remove the timing belt.

That'll teach that engine to make weird noises.

[Aleman]

That'll teach that engine to make weird noises.

LOL! Why didn't BMW just use a timing chain on the M20 - like every other engine they've made?

I'll get to the bottom of it one way or another. I tend to assume to worst - like maybe an oil passage is clogged, and the noise is from my crankshaft bearings disintegrating. I'll point my stethoscope at the PS pump to rule it out as the source. Thanks for the ideas - I'll update the thread when I figure it out.

[digger]

what brand belt, brand idler/tensioner did you use?
how did you tension it?

[MrBurgundy]

Honestly, at this point- just m10 swap it

[McGyver]

is it like, a sexy groan?

[roguetoaster]

is it like, a sexy groan?

We're all familiar with the noises that your mom makes....

[McGyver]

We're all familiar with the noises that your mom makes....

Glad to know someone's taking care of her, but i'll never call you dad!

[VintX]

Hey E30 hive mind -
Have you ever experienced a loud groaning noise coming from your running M20 engine following a timing belt change?
The noise was not there before the TB change, and it starts immediately when the engine starts.
It keeps making the noise even after reaching operating temp.
I suspect a faulty (new) belt tensioner, but I can't get my mechanic's stethoscope in there to confirm it. I did confirm it's not the alternator.
Any way I could confirm the tensioner w/o taking everything apart and basically re-doing the TB job? I may not have found the right angle to get the stethoscope in there...
TIA

If it started immediately after the TB job, it’s almost certainly something in the timing drive.

Most common causes on an M20

• Belt too tight
• Faulty new tensioner bearing
• New water pump starting to fail
• Timing cover lightly rubbing the belt

Quick check: pull the accessory belts and briefly run it. If the noise is still there, it’s behind the timing covers.
Unfortunately, there’s no real way to confirm the tensioner 100% without at least pulling the upper cover. I wouldn’t ignore a groan from that area on an M20.

[VintX]

Hey E30 hive mind -
Have you ever experienced a loud groaning noise coming from your running M20 engine following a timing belt change?
The noise was not there before the TB change, and it starts immediately when the engine starts.
It keeps making the noise even after reaching operating temp.
I suspect a faulty (new) belt tensioner, but I can't get my mechanic's stethoscope in there to confirm it. I did confirm it's not the alternator.
Any way I could confirm the tensioner w/o taking everything apart and basically re-doing the TB job? I may not have found the right angle to get the stethoscope in there...
TIA

If it started immediately after the TB job, it’s almost certainly something in the timing drive.

Most common causes on an M20

• Belt too tight
• Faulty new tensioner bearing
• New water pump starting to fail
• Timing cover lightly rubbing the belt

Quick check: pull the accessory belts and briefly run it. If the noise is still there, it’s behind the timing covers.
Unfortunately, there’s no real way to confirm the tensioner 100% without at least pulling the upper cover. I wouldn’t ignore a groan from that area on an M20.