A/C knocking ?

[ColoradoSilverado]

A couple of day's ago my A/C starts to make knocking noises. When i turn on my A/C it will start knocking, looking and listening under the hood it's clearly coming from the A/C compressor (hold a long handle screw driver against it to my ear), as soon as I turn off the A/C it stops. Anyone ever had this problem ?

Bert

[jyount]

no, but isolate it to the clutch or the compressor, sounds like you have a bearing out in your compressor. Alot of places won't put a clutch on, as compressors are relatively cheap with a new clutch installed. Only thing, if you have a slim tool, it may be able to be replaced without even taking the compressor off, which would mean money in your pocket...

[2000CAYukon]

I would also check that the tensioner is not bad making the noise. A stethoscope can be used to determine what is making the noise.

//2000CAYukon

[ColoradoSilverado]

Originally Posted by 2000CAYukon

I would also check that the tensioner is not bad making the noise. A stethoscope can be used to determine what is making the noise.

//2000CAYukon

You're talking about the serpentine belt tensioner ? Wouldn't it be noisy without the A/C runnig ?

Bert

[2000CAYukon]

Originally Posted by ColoradoSilverado

You're talking about the serpentine belt tensioner ? Wouldn't it be noisy without the A/C runnig ?

Bert

AC is a serperate belt and tensioner. Look at it from the bottom.

//2000CAYukon

[ColoradoSilverado]

Originally Posted by 2000CAYukon

AC is a serperate belt and tensioner. Look at it from the bottom.

//2000CAYukon

My mistake, I'll have to check it tomorrow.

Thanks,
Bert

[j cAT]

if you are low on refrigerent or/and refrigerent oil the compressor will make noises...I had this happen back in 1990,, on my 1983...

check pressures,,,,ever add refrigerent oil???
if you add oil you need pag 150...4oz...should be suffecient..

[ColoradoSilverado]

Originally Posted by j cAT

if you are low on refrigerent or/and refrigerent oil the compressor will make noises...I had this happen back in 1990,, on my 1983...

check pressures,,,,ever add refrigerent oil???
if you add oil you need pag 150...4oz...should be suffecient..

How do I check it ?

Bert

[jyount]

Originally Posted by ColoradoSilverado

How do I check it ?

Bert

You don't! If you are low on oil it is because you also have a refrigereant leak. NEVER just add oil to a system, the refrigerant +oil included. Compressors move gases, not liquids, if you put too much oil in, your compressor will have catastrophic failure. Accumulator systems like automotive a/c systems are more forgiving, but to much oil is just as bad as not enough. Trust me on this I have ac training and certification. The only safe way to check oil is to drain it all out flush the system, check what you got out, and put new in. Unless you had a big leak, the amount of oil lost is negliable anyway. Refrigerant oil is carried through the system because it is carried with the refrigerant, put in more than the refrigerant can hold and your compressor is pumping liquid, not good.

Your tensioner WOULD make noise anytime, because the a/c belt is turning no matter if its on or not. I still say that you probably have a bearing knocking in the compressor. The only time it is turning is when the a/c is on.

[ColoradoSilverado]

Is it possible to leave the hoses on the compresser and unbolt it from the engine so I can take a look at it ?

Bert

[jyount]

Originally Posted by ColoradoSilverado

Is it possible to leave the hoses on the compresser and unbolt it from the engine so I can take a look at it ?

Bert

Being where it is I would say no, if you get under it with a piece of fuel line used like a stethoscope I bet you can hear it and pin point it with it in place. I bet your clutch is shot, like said though, you may not find a shop that will replace just the clutch....

[ColoradoSilverado]

I know they sell just the bearing or clutch/bearing kits but I don't know if it's something I can do myself.

Bert

[ColoradoSilverado]

Also, how do I find out which brand compressor I have, they list 3 different models.

Bert

[J0R0]

Theres a sticker on the comp. w/model # on it. Chances are if it makes knocking noise at idle you have a broken rod in that comp.Replace the comp,dryer and orifice be sure to flush the system to remove any debris you should be fine.Here's a tip when you remove orifice check for debris.No debris means you don't have to flush it....Good luck.

[ColoradoSilverado]

Does it has to be the same A/C compressor like the one that's on there now ? I mean, if I have a HU6 compressor can I replace it with a Denso compressor ?

Bert