NBL

1991 C2

Went for a drive yesterday and noticed a chirping sound coming from the engine bay which turned into a knocking sound. Back at home I tried it out when cold and hot but it's there the whole time. The knocking sound comes and goes, but the chirp is there and mostly noticeable when you first accelerate. It disappears when you continue to accelerate. Sounds expensive.....

I thought it might be the belt tensioner - so tied it back. Wasn't that.

Also thought it might be the air con clutch - so took off the air con belt. Wasn't that.

It sounds like it's coming from the right side of the engine - looking forward into the engine bay.

Here is a recording, you can hear the chirp, but not the knock.

So hard to diagnose over the airwaves, but I thought someone might have a similar experience. Planning to rebuild the engine soon anyway, but would be good to know what is going on here first!


Thanks in advance and stay safe.

CraigC

Look inside your fan shroud with a flashlight and see if you see any scrap marks from fan hitting the shroud. The chirping noise is often caused by a bad fan bearing or alternator bearing going out. Lots of info on how to fix on this website
good luck

NBL

So...checked the inside of the fan shroud and found scoring. Had a good look at the fan, and there are fine cracks in it....time to go. Gave me the push to drop the engine and do the tip to manual conversion....see my soon to be other post