New AC .Belt sqeal Problem

[ozkiwi]

I had a new four seasons AC compressor fitted to my 86 c10 and it has belt squeal when the compressor is engaged.I fitted a new dayco V belt and I think it is the right tension but it still sqeals whenever the compressor engages even when idling.
I noticed the compressor clutch pulley has black anodized paint on it and was wondering if I should scuff this up to help the belt grip?

Also how tight is too tight for the compressor belt?

[chengny]

Push down hard with your thumb on the top run of the belt - the section that runs from the fan pulley to the compressor. The belt shouldn't deflect downwards more than 1/2".

Hardly high-tech, but it's a good rule of thumb (NPI).

[tucsonjwt]

My 83 A/C belt squeals because the smog pump does not allow proper tightening of the belt. If the belt is tightened enough to stop squealing it puts too much pressure on the A/C compressor and puts a strain on the bearings. You can do a two man tightening of the A/C belt - one strong man (or woman) pulling back on the compressor (or alternator) with a pry bar while the other tightens the adjustment bolts. Even with that, the belt will loosen/squeal after a short period of time. Personally, I think the smog pump throws off the geometry of the pulley/belt system, but I am no engineer.

I don't know how much tightening of the belt is too much, but the last time I had the A/C serviced there were two ~ 300 lb. red faced mechanics leaning hard on a big pry bar and wrench while tightening the belts, so I guess they figured there is no such thing as too much tightening. Maybe they thought this would hasten the demise of the compressor and lead to another expensive compressor replacement.

[ozkiwi]

With the old compressor and belts it did not squeal at all so maybe the new one has more resistance.It sure cools better but the that noise will drive me nuts.

[ozkiwi]

Here's a video on youtube worth a 100 photo's and 1000 word's

https://www.youtube.com/watch?v=6Yv9...ature=youtu.be

[jetmech85]

You may look at the possibility of the system being slightly overcharged.

[gmachinz]

A serpentine conversion solves all problems.

[ozkiwi]

No Slipping or squealing now But are the belts too tight ?

[frank69]

I've had this problem and went to a wider belt that ran a little higher in the pulleys. I agree with jetmech that it might be a little overcharged.

[jetmech85]

Yes, it seems to me that they use a very small belt to drive the compressor. You didn't say if you are using R-134a or not. I am going to convert mine when I get a new compressor but I'm wondering if R-134a operates at a higher head pressure than R-12? Just googled it and it does run at a higher pressure.

[ozkiwi]

Originally Posted by jetmech85

Yes, it seems to me that they use a very small belt to drive the compressor. You didn't say if you are using R-134a or not. I am going to convert mine when I get a new compressor but I'm wondering if R-134a operates at a higher head pressure than R-12? Just googled it and it does run at a higher pressure.

Yes R-134a used.
If I had my time again I would have upgraded the whole system to a modern system as the old style compressor is not very efficient.
However no body has actually answered my question in the video.Are those belts over tightened?
I have no issues now but had to put a lot of tension on those belts to get the belt's not to slip.

[jetmech85]

Found this on you tube:

How to Test Belt Tension with a Krikit Gauge...

Less than $20.00 on Amazon.

[ozkiwi]

Originally Posted by jetmech85

Found this on you tube: How to Test Belt Tension with a Krikit Gauge Video - Pep Boys - YouTube
Less than $20.00 on Amazon.

Thanks I love gadgets and will order one today.

[jetmech85]

Yeah, me too. Now just have to research the correct tension for our belts.