So on my 2000 Disco I have had a screaming sound that increases with engine RPM. It is so loud that it embarasses me to drive the car anywhere...my wife can hear me coming home 1/2 a mile away from my house. My work colleagues all know when I've arrived in the parking lot.
Within the last 30 days I've replaced the water pump, both 70mm and 80mm idler pulleys, the tensioner pulley and assembly, fan clutch and 2 serpentine belts (all Genuine Land Rover Parts)....but to no avail, screaming still there.
Finally I decided to try some belt dressing made for a serpentine belt (should have tried this first) and wouldn't you guess the screaming stopped...for about 15 minutes.
I have since gone through 3 cans of belt dressing and still the screaming Disco remains.

I cannot take it anymore, please someone help.

Suffice to say, this car originally had the ACE system which I removed last summer and converted to swaybars and a smaller non-ACE serpentine belt. Could the screaming be related to something not being inline correctly when I removed the ACE pump?

 

Does the A/C compressor disengage? Is there a difference with the A/C on and off?

 

Take the belt off - turn it around and put it back on. If the belts not too smoked this "may" work. Sometimes the way the belt is grooved it puts one side against the pulley = makes screaming noise!

 

The screaming occurs whether the A/C is on or off. I'll try turning the belt around. Should I buy a third belt since the one now in place could be ruined?

 

Wolke has the right idea...check the AC compressor pulley. The pulley could be locked up and not spinning.

 

just to clarify, you can see the clutch on the compressor engage and disengage?

 

Remove the belt and turn each pulley, listening for a noise, you will find it. Once repaired, have fun getting rid of all the belt dressing crap.

 

Do what Mike said. If you don't find a bad pulley, go through each one with brake cleaner and clean the grooves out. Be careful not to get it into any of the bearings. Put towels under each one you are working on. Clean out each pulley and put a new belt on when you are done.

Belt dressing is crap.

 

when I remove the serpentine belt to reverse it I will also turn each pulley to see if I can detect a squeak. Since I replaced all of the pulleys that normally wear, I assumed that the pulleys were not the problem. In addition, if the screaming noise was pulley related, why would spraying belt dressing stop the sound temporarily? Wouldn't the screaming sound continue while I was applying the spray? The clutch on the A/C compressor is engaging and works correctly.

 

It isn't a pulley, but the crap in the grooves that is doing it. Before you do anything, start it and spray armor all on it. It is not a permenant fix, but will last longer than belt dressing and give you time to get a new belt. The belt dressing is horrible stuff and needs to be removed from everything before putting a new belt on.