VR Commodore - rattling noise from front of engine

[mar06mir]

Hi guys,

The noise comes from the front end of the engine, somewhere around or just below the water pump. It started a month or so ago as an intermittent rattle. I replaced the tensioner pulley but no change. It's now intesified and can be heard all the time from inside or outside the car.

I removed the belt and it disappeared. I checked all the pulleys (power steering pump, water pump, alternator, AC compressor, harmonic balancer and tensioner) first by listening while running using a long scewdriver (except HB) and then by hand when stopped and belt removed and they are all OK.

I am quite positive it comes either from behind the front cover or gets transferred to it by the harmonic ballancer. The balancer looks OK. No rubber damage can be seen or felt from the front. When pulled to one side it flexes a bit but I think it's normal.

Have you ever heard of a HB that is crucked although it still looks good? Mine is about 3 years old recon. Can it cause problems when under load and run OK with no load, ie belt removed?

Second possibility would be the timing chain or/and its tensioner or sprockets but it puzzles me that the noise stopped when I removed the belt although the chain etc are still spinning.

Any suggestion?

Oh, it's a 1994 VR II Commodore with AC, about 280K kms.

[OzJD]

I would guess that if the belt is removed and there is no noise, that it's something attached... power steering pump, water pump, a/c compresser etc.

[hako]

That HB sounds a bit suspect - with the engine running and belt installed check to see if it's wobbling or moving slightly.
If OK it should not move at all with the engine idling. Any movement and its a definite suspect.
Removing the belt removes the load from the HB so it wouldn't make a noise if buggered except with the belt on. Good Luck.

[calais_cruzin]

^^^ yes there should be no wobble in the HB, mine did for 6months then ate itself to bits.

Sure its not the bearing in ur alternator, i had one that would intermittenly make wierd noises, when i spun it, it was fine, but put a bit of pressure on it as u spun her n she would clunk, bearings would dislodge n rattle, but spun perfectly without a belt.

[mar06mir]

Many thanks. Will check it again tonight. The bugger is less than 3yrs old and looks in prime cond although somewhat soft. When pulled by hand on one side it visibly deflects.

[hako]

Many thanks. Will check it again tonight. The bugger is less than 3yrs old and looks in prime cond although somewhat soft. When pulled by hand on one side it visibly deflects.

That confirms it's definitely the harmonic balancer. I hope it doesn't fail completely before you get a chance to change it as they can take out a radiator, aircon condenser. CAS etc in a few seconds when they detach but I guess you're aware of that seeing as you've replaced it before.
Top marks for you description and followup

[mar06mir]

Hako and calais_cruzin, you seem to know a thing or two about cars.

It was the HB. This is the fourth that I've replaced on various cars so far and it was different from the previous ones as there was no signs of damage on it whatsoever. Usually the rubber cracks or disintegrates and the noise starts rather quickly. This one stiil looks like new and the rattle became louder and louder over a couple of months. As I said earlier, it only seemed too flexible when pulled by one side but looked fine when spinning, ie no wobble.
Once again, thanks for your help.

[savage1987]

Did it cost much to change? My VN is noisy as hell, could be part of the reason why. It's also got 500,000++ kms so the bearings would be playing a part as well I suppose

[mar06mir]

Savage1987,
I did it myself. 1/2 hour job if you have the tools and if you know how to do it. I paid $130 for a new one which was a very good price. They are usually $160 plus.
In your case with 500+K it could be many things. Yes, bearings, HB, valves, exhaust, engine mounts, loose bolts etc etc. Worn bearings usually produce grinding or whinning noise, stuffed HB rattle or knocks very loudly. With 500+K on the clock I would be looking for a second hand or recon engine. Might cost you less than start fixing all the probs, especially if you can't do it yourself.

[savage1987]

Thanks for the info mate, looks like I'll be looking into a replacement motor soon anyway.. too many bearing noises and too much piston slap and ring wear.

Don't worry, I wasn't putting it all down to a stuffed balancer, just one of the many noises it's making (and has for a good while).

I do everything on my cars myself, as I will when it comes to a motor swap.

Cheers
Sam