Clunk noise in engine bay 94 BRM

Guys,
when my engine is idling, theres sometimes a single clunk noise whats not corresponds at all to any engine orders. This noise comes up estimated one time a minute ( I still didn´t measure it, can do it yet) . The noise occurs just once, one hard, single clunk, without any attending ambient noises. Might be that this noise takes part as well when driving, but then it might be perished by general driving noises. I sounds as a hot exhaust system cools down and loses its tensions, sort of those noises, but only a single clunk and a bit harder.

Any experiences or assumptions?

Udo

Did you look at your AC compressor clutch?

@Fred, no I didn´t  do as yet. Had no idea what it could be, but i want to replace my serpentine belt anyway and will check it in that course. Would be a good idea to replace the tensioner as well, could this probably cause the noise? If it´s the compressor clutch, is it to feel once the belt is off? Is the clutch easy to replace?

Udo

It is not an easy diagnosis without standing in front of it.

back it up to the keyboard,... we'll se what we can do,.

Have to look how to do this...never did it.

Fred Kiehl wrote:

Did you look at your AC compressor clutch?

@Fred,
almost one year ago, but you was right. It´s definitly the clutch of the AC compressor. As long as the AC is off, there´s no more clunk at all. Once I put it on, it starts to clunk frequently again. You hear it without any doubts in front of the car when it´s idling. My question: Is there anything to pay attention to change it? Any different supplier parts which might not fit?

Apart from this, one question concerning the heater hose routing to the heater core. I ´ve had a leakage due to a broken plastic connector between the two hoses from the water pump to the heater core. The connector was broken inside the hose whilst the clamp was tight anyway. I digged out the broken chunks and found that the connector has inside a small soft spring with a plastic ring ( it looks first like a throttle, but it isn´t)  It seems to me as it might be a damper to reduce gurgling noises from the water circuit. Am I right? I have replaced this part by a simple plastic tube what I found in my garage. I can´t suggest that there´s any issues coming up but I would like to know your opinion.

Thanks a lot

Udo

I do not know if the compressor is making the noise, or the clutch. The parts are both available from Rock Auto. If it is the compressor, and you allow it to fail (it may already be too late) you must flush the whole AC system to avoid the "black death" for a new compressor.

The part is a restrictor so that the heater core does not get too much hot water. I am not sure how it works, but you should replace it with a new one, and not just a tube. You can get one from Rock Auto for about $17USD plus shipping. The 92-96 part is the same for all B-bodies. It is called a heater valve in the heat and AC section.

The compressor makes a clicking clunking noise when it engages the clutch
Watch the a/c pulley as its idling.

phantom 309:
Yes, it´s a exactly that sort of noise, do you think thats normal and ok even when the AC compressor and the clutch are ok?  You here it as well inside the car when idling, not when driving, at least probably very small.
My AC is working fine, would there be any issues coming up with the AC if the compressor starts to fail in any way? I´am a bit of helpless if there´s any need for action. On your cars, is the AC clunking frequently as well, maybe once in a minute when AC is operating?

If I watch the AC pulley when idling, what should happen once something is wrong? There´s nothing happening unless the clunking noise when the clutch is working.

If the compressor is failing, you may have already passed the point of flushing your AC system when it does fail. If it is just the AC clutch, you can replace it without replacing the compressor. If you must replace the compressor, you must also replace the orifice tube, and possibly the accumulator/dryer. All of the components MUST be flushed, and produce clear cleaning fluid out of them.

There should be no clunking when the AC compressor is running. The only thing you may feel is when it engages and disengages, but you should not hear it. The only sound it should make is a slight click when the clutch solenoid engages, then it should run absolutely quietly. If it is engaging and disengaging frequently, you may need some refrigerant. Have the pressures checked.

inmho,. the noise you are hearing is a healthy a/c clutch,. could be the idler is a little weak and you're getting belt slap,.

but,.. maybe back it up to the keyboard and we'll know better,.

or try a youtube video,.