K20 engine noise - nasty squeel

ChrisD. · 23 Jun 2017 at 08:40

Drove the Teg for the first time in a few weeks yesterday and half way into the drive I heard what sounded like the alternator belt screeching. I *think* it rises and falls with the engine revs, and it definitely sounds like a belt when you turn the engine off as there is what sounds like belt slip. However the noise is coming from the intake manifold area, possible underneath it and closer to the airbox side than the belt itself.

https://1drv.ms/v/s!Ar91VtA-qfT8geZZRry4mZLSF7WjjQ

I'm not sure if that link works as OneDrive is blocked in work.

Any ideas? Water pump bearings perhaps?

pastymuncher · 23 Jun 2017 at 09:50

Holy crap, that sounds like a bandsaw!! Is the belt rubbing against anything?

ChrisD. · 23 Jun 2017 at 09:51

Not that I can tell. Thing is, the belt is on the left and the noise is definitely over to the right. Could it be the intake manifold leaking slightly?

Howard · 23 Jun 2017 at 09:57

That sounds like metal on metal to me. Perhaps a knackered bearing or pulley.

bJN · 23 Jun 2017 at 10:01

That is not a pleasant sound...

Hard to locate the sound on video, but I'd be more inclined to think of pump bearings over belt / rubbing. Can't say I ever experienced it with mine when I had it. I wouldn't have thought an air leak would cause that much noise either... Dodgy injector perhaps?

ChrisD. · 23 Jun 2017 at 10:03

Howard said:
That sounds like metal on metal to me. Perhaps a knackered bearing or pulley.

Yeah same but it's more on the right and as far as I know all the pulley systems etc are on the left of the engine.

Dup · 23 Jun 2017 at 10:17

Could be anything from pulley, tensioner, or water pump bearings or maybe PCV valve. Sounds more air hissing than metal on metal to me.

Curveball idea, you're running 0w-60 right? Maybe the oil pump is having a hard time. GM engines like in Saabs have an issue with oil sludging up and the oil pump would scream like this:

https://www.youtube.com/watch?v=gH0ztn1QzMQ&t=3s

ChrisD. · 23 Jun 2017 at 10:19

Dup said:
Could be anything from pulley, tensioner, or water pump bearings or maybe PCV valve. Sounds more air hissing than metal on metal to me.

Curveball idea, you're running 0w-60 right? Maybe the oil pump is having a hard time. GM engines like in Saabs have an issue with oil sludging up and the oil pump would scream like this:

https://www.youtube.com/watch?v=gH0ztn1QzMQ&t=3s

I think I just need to get it to a garage but I'm concerned about driving it. I may arrange for it to be transported to be on the safe side. Luckily I don't need a car now so can do without it for a week or two!

10w-60 which I've been running on and off for about 8 years without a single issue.

ChrisD. · 23 Jun 2017 at 10:26

Just spoke to Tom at TGM, he said it's either the pulley tensioner, PAS pump or alternator. I said it sounded more like around the intake manifold and he said that the RBC is known to crack and it could be that. He said to spray some brake cleaner over it and see if the engine starts laboring. He said it's fine to drive so I'll probably take it down tomorrow or something.

kaiowas · 23 Jun 2017 at 10:33

How easy is it to pop the belt off on that engine? If it is something on the belt then the simplest diagnostic technique is to remove the belt and turn the various pulleys by hand until you find one that's a bit tight, doesn't turn smoothly or makes odd noises. It's generally pretty obvious when you've found the issue.

ChrisD. · 23 Jun 2017 at 10:37

It's pretty easy but I am a mechanical idiot so I'm not sure that's something I want to do myself.

Dr Who · 23 Jun 2017 at 14:15

Sounds like the rear alternator bearing which would throw the sound over to the right....

ChrisD. · 24 Jun 2017 at 15:48

It was the RBC adaptor plate which was really loose. One of the bolts needed a few turns and to be honest all needed tightening. Now idles better than never.