squeaky belt

Anyone know what caused the auxiliary belt (mini vee) to squeak?
I've dosed the back of the belt with talcum powder most of which ws blown into my face by the fan), and silicon lubricant; the noise disappears immediately, so I'm happy it's not a squeaky bearing in one of the pulleys, but then gradually returns. Any ideas? It's a 300 diesel in a p reg Disco.
Cheers in advance
George

Squeaky belts have been discussed a lot on here, you might like to do a search and see if anything else jumps out at you.

Also , are you sure the belt is the correct length?

There is also the penny trick. Again worth a search.

Good luck,

Cheers

I tried the penny trick a couple of years back and it gave me a squeak free aux belt for about 9 months or so iirc, until one day when sat at the lights there was a bang and the stud that the tensioner assembly sits on snapped!

I then had to try and drill and extract it (which thankfully worked) and fit a new tensioner and stud. I was then squeak free for another 18 months until it became noisy again. In the last 6 months I replaced the belt, so it wasn't that, but I put a very thin washer in behind the tensioner at the very outermost edge and that was just enough to shut it up.

To Compare the before and after effects, I sprayed some WD40 on the top of the belt until the squeak went away, then looked across from the air filter side of the engine bay until I could see the shine of the belt as it runs over the top of the water pump pulley:

BEFORE: After about 30 seconds the shine on the side of the belt nearest the timing case disappears as the oil dries due to friction, and the squeak starts to come back.

AFTER: With the very thin washer inserted and lube sprayed on the belt it takes about 50 seconds for the lube to (mostly) dry off the belt and it shows on a wide strip of the belt, which tells me that the surface friction of the pulley is less, and the pulley is running a lot truer than before.

Without being able to measure the exact angles of the pulleys it's hard to tell when they're aligned, but the light lube trick seems to work well as long as you can see the shine over the surface of the belt that has just come off the tensioner pulley.

I hope that is helpful, even if a little rambly

Just to add to the above, I think that eventually any new tensioner will start to make a noise because of the well known problem of he casting misalignment, but adding a penny is too much for the stud to take in the long term, so use the barest minimum thickness washer that you can get away with..

Thanks to all for the useful comments - it was the first time I'd heard of pulley mis alignment being the cause!!
Will also search previous posts. Thanks again.

George from pembs

New belt

thanks - I'll do that anyway before I start looking at the trueness of the pulleys!
Bye the bye, how do I thank more than one member for their posts? Is i tenough just to reply to the thread, or do I have to name them individually??
George

Some experiences regarding different brands of belts here which may help
https://www.landyzone.co.uk/land-rover/aux-belt-squealing.298966/
https://www.landyzone.co.uk/land-rover/squealing-fan-belt-fixed.300257/

George Bazeley said:

thanks - I'll do that anyway before I start looking at the trueness of the pulleys!
Bye the bye, how do I thank more than one member for their posts? Is i tenough just to reply to the thread, or do I have to name them individually??
George

Click to expand...

Good question! I think protocol is to "like" the posts - at least that's what I try and do - and I also use it as a way of agreeing with a post which I think answers the question posed....

And, +1 on the new belt by the way... I tend to use Dayco - IMHO, steer clear of S***part

Well, I seem to have cured the belt squeak - bought a new tensioner, same spec. as Land Rover genuine, but much cheaper at around £39, but left the belt on as it wasn't that old, and hey presto, squeak gone! Fingers crossed it stays away. It's still very mysterious as silicon lub. applied ONLY to the flat side of the belt makes the noise disappear temporarily, so it must be some sort of interaction between an old tensioner pulley and the belt............v. odd!

After the squeak removal, I've recently done 500 miles in a day, one way towing a 3500kg trailer with pre war car on board, so the Disco was working v. hard; on the return (m4) I noticed a very unusual smell of "some sort of oil burning" type. At the next services I had a look underneath and was dismayed to see most of the underside of the Disco smothered in oil - it was some of this ending up on the exhaust which I had smelt........

At home, and up on the lift, I am fairly sure it's gear box oil, and I think I can see at the top of the box a small diameter (6mm?) black plastic tube which seems to have split in two, or come adrift somehow - could this be a breather?? It seems to originate at the transfer box.

Anyone got any clues from similar experiences??

Cheers in advance

George from Pembs

George Bazeley said:

Well, I seem to have cured the belt squeak - bought a new tensioner, same spec. as Land Rover genuine, but much cheaper at around £39, but left the belt on as it wasn't that old, and hey presto, squeak gone! Fingers crossed it stays away. It's still very mysterious as silicon lub. applied ONLY to the flat side of the belt makes the noise disappear temporarily, so it must be some sort of interaction between an old tensioner pulley and the belt............v. odd!

Click to expand...

The "flat" side of the belt wraps round the PAS pump pulley. What folk have found is some brands of belt have a rougher and more grippy flat side than others and seem to work better. I think the squeak, at least it seemed so from my experience, was due to a tired tensioner and a new belt with a less grippy flat side. Putting lube on the flat side may encourage slippage at the PAS pump when under load and sudden heavier steering.

Oh yes, the application of some lubrication is just a tool to find out if it stops the squeak!

Oil on your belt? When my injector decided to spew diesel over my engine it squeaked like hell. Now an oil pipeline has gone and done the same and he noise has returned!