A/C installed, belt squeal on start up

[Paul G]

I just got the A/C all together and charged up. Bought an A/C kit from Bouchillon which has the dryer, cond. coil, valves and hardware. Got a Sanden serpentine compressor from Summit, and it all works good with the factory coil in the dash. Blows cold!

The problem; At engine start up with A/C off, or with engine running and the A/C is switched on, I get a bit of belt squeal. It has a March serpentine set on it. Brand new Dayco belt driving the A/C, PS, and WP.

Any ideas?

[62 Max]

Squeal = loose belt.

[Paul G]

How tight should a serp belt be? I have it pretty darn tight.

[A383Wing]

Probably a little more tighter than it is now.

Or your AC compressor is too tight to turn with load? Who charged the AC? What are the low & high side pressures with AC turned on??

[elacruze]

Give a photo? March doesn't have one on their website.

Belt wrap on an A/C compressor *MUST* be at least 30%. Preferred is 50%.

Serpentine belts are usually just tight enough to make you wince and go "I think that's too tight".

[A383Wing]

That might be the problem with the alt as well...it may not go around it far enough to "bite" the pulley

[Paul G]

Pics of the pulley set. Kind of hard to see.

[elacruze]

Belt wrap looks fine.

Do a test, run the steering all the way to a stop and see if you can make the belt squeal the same. If so, it could be the belt squealing on the coated pulley, and it may resolve with a few more miles.
How much tension is on the belt? You shouldn't be able to move it more than about 1/2 inch deflection. If it flops around at all while running, it's way too loose.

[A383Wing]

Looks like there are 2 belts there....are you sure it's the alt belt making noise and not the AC belt?

[Paul G]

I dont think it is the Alt belt. I will hear the squeal when I click the A/C on, and it will squeal a bit at start up. 

[elacruze]

It's possible that the alternator belt is the culprit. When you first start the car, the alternator has a moment of hard work while it replaces the battery voltage lost to the starter. Also, when you turn on your A/C, the blower fan pulls some on the alternator too. You should be able to do some experimentation and disprove this theory if not the case.
Check to see if you can make it squeal with the bright headlights, wipers, heater-only blower fan, etc.

[Paul G]

That alt belt is an Auto Zone belt. I had to get a longer belt when I put a mechanical fuel pump back on the motor. I had no time to wait for a mail order belt. I dont have much faith in anything from AZ.  The A/C belt is a Dayco from Rock Auto. You can tell the Dayco is a much better built belt.

[elacruze]

Simple test, if the belt squeaks every time-get a spray bottle with water, and squirt a little on one belt or the other to make the squeak go away. Of course you need a partner to activate the A/C.

[Paul G]

Had some time to work on it today. The PS pump was not in very good alignment. Overall I am not too pleased with the March setup. I have had to use washers to shim, and grind off some length on various spacers in this kit to get the pulleys to line up. Had to do that again with the PS pump. Once it was in a little better alignment the belt would not go back on. Too short. Went and got a longer belt. So far no squeal! I hope that was it.