Hello all, I have a 1998 Discovery with 82K on the clock, and a squealing serpentine belt under the hood. I have changed the belt twice, tensioner, water pump is new, routing is per RAVE manual. A new belt is good for a few hundred miles, then it starts doing it again and gets progressively worse. Let's see, some random fun facts.... it's fine at idle, kicks in with a squeal as soon as I get on the gas. It's much better cold and gets progressively worse as the engine warms up, which led me to think that it was squealing on the water pump pulley when the fan clutch started to engage and sure enough, if I hit it with a little water as it enters the water pump pulley it stops completely. Until the water dries, that is. It smells like a tension issue, but the tensioner is brand new and a decent one at that, and the belt is pretty darn tight, way tighter than the one on my Jeep that has never uttered a peep in. I spun, wiggled, and jiggled all of the pulleys and everything is smooth and tight and soundless. Any thoughts and advice would be most appreciated !!

 

The belt is too tight..

And sorry for the stupid question, but are you sure all the grooves are lined up? Sometimes the simplest isn't always the most obvious (computer won't turn on - is it plugged in?)

 

Yes, funny you should say that because I just went out and checked that again. Belt is from Napa, ~ $50 but in stock for instant gratification. It seems to fit pretty well and position the tensioner where it is shown in everyone's pics online of belt routing. Wouldn't the tensioner (new in this case) keep a constant tension on the belt and compensate for small variations in length ?? No problems getting the belt on whatsoever. The squeal seems to be coming from the flat side of the belt where it engages on the water pump pulley, a little water in that location quiets it right down momentarily.

 

There is drag on the belt. From something it turns, when it warms up that thing is trying to sieze up. Perhaps listening via mechanic's stethoscope or long screw driver or yard stick to various items (water pump, idler pulleys, alternator, power steering pump, etc.) when cold and again when warmed up will reveal sounds you can't hear over motor noise.

Sometimes a screw thru a board at 90 degrees can be used to touch the mounting bolt on a pulley.

Be careful when working around rotating parts. Wear eye protection, a pulley and belt love to grab dreadlocks, carelessly held tools, fingers, etc. You can also take the belt off and turn things by hand, more difficult with hot items. Changing a hot alternator on the side of the road in rush hour traffic will teach you the value of gloves.

 

Thank you for the reply, I was just out there cleaning the pulleys and grooves meticulously but to no avail and did a pretty thorough job of spinning and jiggling all of the pulleys with the belt off and everything feels silky smooth. I agree with the drag theory, it definitely gets worse when things heat up and the fan clutch engages. But even when hot, things still spin smoothly and freely. Maybe Napa belts just suck.

BTW, it takes less force to pull back my brand new Dayco tensioner than it does the original.

 

Something else to keep in mind.. worn out bearings don't like to be spun freely when there's no directional tension on them. They'll change location and tend to wear out faster. Yes I realise this doesn't make sense in design, but the physical properties of the rotational forces on the rollers have a little play between them to allow movement.

Water pump is new? As in brand new, not "used, new to you"?

I remember when I bought my truck, water pump and fan clutch were the first things I had to replace. Got them from Paul Grant and haven't had a problem since. Old water pump bearing was so worn out, it was flopping all over the place...

 

Water pump is brand new, to me or anyone else who would have bought an OE water pump from Atlantic British. Man this is frustrating.

 

To eliminate the problem via the belt or pulley, go get a cheap belt just to see if the squeal persists.. that's all you can do, process of elimination.

Did you spray belt dressing or white lithium grease on it by chance? You should never use that stuff on a serpentine belt. If you're gonna use it though, use a silicone based spray instead, not lithium.

 

Nope, somewhat smarter than that. I do know that spraying gunk on the belt will only end up making matters worse, or masking the real problem. Tho I have to admit I almost put a little brake fluid on the belt on the advice of an old hot rodder friend of mine just to see wtf would change, but didn't succumb to the temptation. Yet. Funny you should mention a new belt, the last two I put on did the same thing but only after a few hundred miles, as soon as the new belt went on the problem went away completely for a while. That's another thing that makes me think it's not bearing related. I've read good things about the gatorback belt, and was just poking around online to see what I could find. What the heck, it can't hurt.

 

Yeah just checking! Surprisingly many people don't know not to use belt dressing on a serp. Usually by following bad advice from a shade tree mechanic or a parts store salesman...

Anyway, hope you get it resolved. Definitely not as bad as my problem I'm having! Ugh..