a/c noises

[apukareem]

With the unseasonably warm weather here in NWPA i turned on the AC in my KJ.

I noticed that it was making a semi-loud (you could here it inside, when sitting idle with the radio off)(or outside easily with the hood open)

Whirring type noise.

The serpentine belt seems ok, but I have no experience with any of that kind of stuff.

When I turn the AC back off, the noise stops.

Besides taking it to a shop, what can i do to reasonably easily test it.

Could it be just a matter of needing the AC recharged, or something more extreme like the bearings inside etc etc.

Also, on a side note, I just replaced the Blower Motor resistor, not that I think it would have anything to do with it, but it may I suppose

Thanks,

 

[TwoBobsKJ]

Did you notice any noises when you used the defroster during the winter? The AC compressor comes on with the defroster too.

Bob

 

[apukareem]

Indeed, I did actually.
Today we're back down to the 40s, and had the heater running.
When I would slow down I would notice the sound again, and after about 30 seconds it would stop.

Could this indicate a different part?

 

[jggv98]

I was having the same issue...

Last week i change the belt tensioner and the belt (Mopar), but we saw that the new belt was a little more big than the original, we install the new belt and after a couple of days it begans the noise at low RPMs (R or D) or when you turn the steering (only with A/C on)

i was thinking it was the A/C clutch, but no

I just get back to my old belt and the noise disappeared

Maybe your belt tensioner is not working or the belt is not the correct one

Good luck!

 

[J'sJeep]

Probably the tensioner. You can also disconnect ac to see if noise persists. Does it happen when in drive or reverse with brake applied? When you speed up it would put more tension on belts and when idling in gear would be less tension and would cause tensioner to rattle. Have buddy sit in the jeep on drive and hold brakes, put screw driver on the tensioner( not just the pulley but the centerpiece holding both pulley arms where it mounts to engine) and see if you feel larger vibration through screw driver there than if you put it else where. This will help isolate where the rattle is. 35-50 dollar part. Waaaay cheaper than ac. Let me know!

 

[apukareem]

Thanks, i'll look into the tensioner.

I notice it when i start it up, or when i'm slowing down (pressing the brakes)

Other than that, i don't really notice it.

How difficult is it to change the tensioner?

 

[J'sJeep]

Simple as hell. Take off serpentine belt then remove single bolt that holds it to the block. Pull it off and you will see a notch. Line the new tensioner notch up correctly when installing it. Tighten it down nice and tight but don't over do it. Put serpentine back and you're done.

 

[apukareem]

Ok, I took a closer look today and did pinpoint that it indeed is the belt tensioner. It is a little loose and i can see it move on its own.

On Napa's website, they have 2 different parts, 1 has a 90mm diameter pulley, and 1 a 76 mm pulley.

Is there an easy way to tell which I would need? Besides measuring my current tensioner

Part Number: NBH 38167 and NBH 39120

I did see some other posts that said Gate's tensioners were better, but I do not have time to order and wait for a part, so are the Napa ones as good?
Another alternative is Advance Auto has a Dayco

 

[J'sJeep]

I went through autozone. Napa usually has good stuff thiugh