air conditioning issues

[newshofan]

For a while now when I turned on my air conditioner their has been a slight rattling or ticking noise that had only last for a second or two. I hadn't thought much of it. Today after work and driving around for while with ac on. I stoped for a minute and when I turned the car on and started to pull away and turned the ac on the noise started and got louder as I pulled away and up a hill.
It had never done that before. I almost panicked when it happened. I shut off the ac and the noise stopped. But everytime I turn on the ac it comes back and gets louder with higher rpms. I did check the pressure with a gauge I have and it read a lil over 100psi which is way to high. Any thoughts? I have an audio clip I took but from my phone I can't seem to figure out how to attach the sound clip. I can email it to someone if they can post it on here.

 

[stephen newberg]

Leaf down in the ventilation system and being flicked about by the drive fan? I have had that and it sounded like that. Do you get it only when on Max AC or in all or most settings for the air system?

pax, smn

 

[newshofan]

It does it in max ac and auto. I haven't checked to see if it does it on any tempature or just ac. I will inspect it more after work. But the leaf doesn't explain the high presure?

 

[newshofan]

I had a mechanic at my work listen to the noise and he said it sounded like it was coming from the compressor. The compressor is staying engaged but it has loud knocking sound. The only time it doesn't make the noise is when set to vent or floor and that's couse the compressor doesn't engage on those settings.
Can this be fixed by flushing the system and adding some oil. Or is my compressor shot. Still haven't been able to check both high and low pressors. Just the one on back and it read 100. It has never read this high before

 

[E1 v2]

Have you removed the little shim inside the clutch yet? You might be hearing the clutch slipping from a little too much airgap.

That pressure doesn't sound right at all.

 

[newshofan]

Had a mechanic hook the car to the ac machine. The low side was bouncy at around 90 and I forget exactly what high side was. But he said he thinks the compressor is about shot and its possible that the orfice tube could be cloged causing the high pressure. And the knock but we wouldn't know till we took it apart.

 

[newshofan]

Does anyone know how hard it would be to change the orfice tube? Also what all could clog the tube and or cause compressor to knock. What all would be best to change?

 

[frankanthony]

I have never done it before but maybe this will help you... doesn't look too hard all though it might but tough to get your hands in there..

 

[frankanthony]

I guess this forum doesn't like .png here is .pdf

 

[Mr Anonymous]

That pressure is perfectly normal if the reading was taken when the compressor was not running.

 

[newshofan]

Pressure was taken with compressor running. But when I checked with my guage with sytem off it said 100psi. I don't have one that fits the high side and I forget what the shop machine said it was. I'm hoping that the orfice tube is the only thing thatgs bad as a two dollor part is a lot cheaper than a 300 dollar compressor.

But the question posed is why would it be clogged. I had noticed a slight knock for a few seconds when I turned on the ac for a month or two leading up to this.

 

[shonuffmine]

If the orifice tube is clogged it would be real high on the high side an real low or a vacuum on the low side,if the clutch is engaging well and you hear a knock it is the comp.Either a shaft bearing or rod(or rotor)

If you are getting 100 psi while clutch engaged and cold air,well no brainer release some a134 ,I like my low side around 40-42 psi

 

[Bob Gervais]

I like my low side around 40-42 psi

Which is also dependent upon ambient temp. The higher the ambient temp, the higher the pressure will read.

I agree about the orifice tube, doesn't sound like it's clogged.

I also agree with checking the clutch gap and removing shims. Sounds to me like the clutch isn't engaging all the way, thus the higher pressure.

 

[Mr Anonymous]

Pressure was taken with compressor running. But when I checked with my guage with sytem off it said 100psi.

Huh? Which is it? Again, if the compressor clutch is NOT turning, 100psi is a perfectly normal pressure to see on the low side.

Regardless, if your compressor is blowing up, your whole A/C system is going to be full of crud and just replacing the compressor and orifice (which is a PITA on V8 cars, just buy a new liquid line) won't work well for long.