99 ranger 4.0 w/AC belt length

[mooty]

All the auto parts stores supply a roughly 88.25 inch belt for this year/model but they never quite seem long enough. The tensioner does not extend much and I'm left to wonder if I have the right belt.

I've been trying to trouble shoot some belt whine issues so I'm curious if you guys have any insight.

I also noticed that the outside of the AC pulley seems to spin separately from the inside. I'm not sure if that's a mechanical failure or normal.

 

[enjr44]

Belt whine is usually caused by a glazed belt or pulley. But, it could be something else. I would start by spraying water on the belt (spray bottle). If it goes away it is the belt or a glazed pulley (probably one of the ones without grooves). Take the belt off and sand the pulley's surface to rough it up some. If that doesn't stop the whine, it is probably the belt. You can try cleaning the slick side of the belt with lacquer thinner.

The AC compressor pulley spins with the engine, but doesn't turn the compressor until you turn on the AC. When you turn on the AC the clutch engages and everything spins.

 

[mooty]

The AC compressor pulley spins with the engine, but doesn't turn the compressor until you turn on the AC. When you turn on the AC the clutch engages and everything spins.

That makes perfect sense, guess I won't worry about the A/C pump.

 

[mooty]

I tried thoroughly spritzing the belt with water and the whine wouldnt quit. I bought a motorcraft belt which is about 88.3 inches as are the generic replacements. It does stretch a hair but bothers me as the tensioner barely extends. It makes me wonder if I own a 98-99 intermediary 4.0 with a different arrangement. I also tried lightly sanding the smooth pulls but nothing changed. It seems to be most prominent after running the fan and particularly the a/c for while. After said use the whine will persist for a while, even if the accesories are off.

I wonder if I have the wrong size belt or if maybe the alternator is over taxed?

 

[mooty]

Just an update on this. It was suggested to me that I replace the tensioner. I ordered the appropriate motorcraft part and found that, although it was the correct part as specified by ford and shared stamped numbers with the old tensioner(original equipment btw), it had a smaller sized dovetail notch. I checked the 98 part in the ford database, it was the same one. I also looked at the gates equivelant which shared the smaller notch. I'm not sure what the deal is there but I wound up using a cutting wheel to make it fit.

So now that the tensioner is on, I noticed the spring is moving when the engine runs. It's like there is some brief tension that pulls and releases rapidly. It may not matter but the change-out didn't stop the belt whine.