Name That Squeal

[berserk_gorilla]

Right people, please can you lend me your expertise? I have a small nag with The Miracle Whip which has been going on for some time now. She has a bit of a squeal, all day, and all night, she squeals and I don't know where from. Here's a short clip...

http://www.youtube.com/watch?v=9VFDuwKwZRY

... if you have a minute and have any ideas or things that I could try that would be cracking. Both fan belts have been changed, for other reasons **cough** snow-incident **cough**, but that doesn't seem to have helped either.

Any ideas would great thanks.


Ben

 

[ggcton]

Sound like a fan or alternator bearing, one for El Hennessay I think Gary

 

[malcolm]

Me Me Me (please sir)

My money is on that daft idler puller on the lower belt. Try spraying some WD40 on the bearing to see if the squeak goes away. Won't sort it - you'd need to replace the bearing but it should identify the cause.

 

[Steve Hennessey]

Just read this - yes it just has to be the idler bearing BUT could also be the front alternator bearing. That noise is of a dry bearing.
These noises are really easy to eliminate because all you need to do is to loosen / remove one fan belt and the lack of noise will point you in the right direction. WD40 is good as it can also help to detect the other 'front end' noise - the squeaking fan belt!

 

[berserk_gorilla]

Still no luck...

Cheers for all your help guys. I am still having a little trouble finding out what the problem is though.

Sounds pretty reasonable what you were saying Gary as I've had some trouble with the battery. I took the fan belt off that goes to the alternator and started the engine but the squeal was still there. Cheers though.

Malcolm and Steve, which part is the idler puller? If you can work your way around this diagrammatic representation I got direct from Renault is it this...

... First tried to WD40 this but with no luck. Then took it off, as well as the other fan belt, but still no luck. Did I get the right bit or should I go back and look again.

It's confused Bobble and myself for the last few months and we are stumped.


Thanks,

Ben

 

[malcolm]

Well I'm stumped too then. The idler pulley is the pulley attached to the part labelled "this bit" in the official Renault diagram. If you've had the other belt off then it's not that.

If the only pulley turning when you've taken off all the belts off is the bottom pulley then my money is now on that or something inside the engine. Though that squeal can only really come from something outside the engine.

Is the bottom pulley coming loose and rubbing against the aluminium gearbox casing? Think it's a 17mm spammer to check the nut, and any visual evidence or rubbing would be useful. Shine a torch down into the hole to see if anything else looks a little too shiny.

Also try getting hold of a piece of plastic hosepipe. Put one end in your ear and move the other end around until you get to the point where the noise is loudest. That'll be the thing we need to look at.

 

[angel]

Clutch release bearing? Does the sound change when operating the clutch pedal?

 

[Steve Hennessey]

Have you ran the engine with both fan belts disconnected at once? There is always the water pump bearing but it is rare for that to make a noise. If you still get the noise with both belts disconnected then could it be something in the distributor?

 

[berserk_gorilla]

Excellent! I thought as much Malcolm, thank you.

Yeah, I've had both fan belts off and the squeal is still there Steve. Water pump has recently been replaced too so I'm glad it's not that.

Bottom pulley seems tight to me.

Got the torch out and it looks pretty grubby down there. No sign of any shinny bits.

Squeal there before, during and after pressing the clutch Angel.

These are all cracking ideas though! Thanks.

I have, however, got some more information on the noise... I went for a little drive and did manage to make the noise disappear briefly. When I'm just trundling along, the noise is there. When I'm stopped, the noise is there. BUT, if I speed up, or pull off from a junction, while the engine is under a bit more strain the squeal does briefly disappear. At least until the car has caught up with the engine.

Does this point the pathology to the engine?

 

[Steve Hennessey]

Lateral thinking mode cap on - it could be a dry rocker on the rocker shaft. It's where it's so gunged up that oil is not reaching the parts that it should. I have come across this just once before. Only way to checked properly is to let the engine tick over with the rocker box off and oil each rocker on turn.

 

[angel]

.

I have, however, got some more information on the noise... I went for a little drive and did manage to make the noise disappear briefly. When I'm just trundling along, the noise is there. When I'm stopped, the noise is there. BUT, if I speed up, or pull off from a junction, while the engine is under a bit more strain the squeal does briefly disappear. At least until the car has caught up with the engine.

Does this point the pathology to the engine?

Wow, this reminds me of something similar I encountered in the past on a Nissan Sunny, and almost got me mad before I found it.
I had exactly the same symptoms (squeal disappearing when engine was under load), and I finally discovered after some six hours of searching...I had applied RTV sealant around the waterways of the inlet manifold to cylinder head gasket (my mistake). Some of this may had found its way around the inlet port joint faces, and disintegrated when it came into contact with the air/fuel mixture. Not only did it cause an air leak there, but it vibrated too causing that squeal, that disappeared when engine load was high (= inlet vacuum low=little air leaking). I refitted new gaskets dry, and voila...no squeal!

Check all inlet manifold and carburettor gaskets for good sealing.