I have new compressor, oriface and accumulator installed. Refrigerant is 134a, car is -87.

We put there 8oz oil + 2,3lbs refrigerant.

Cooling is ok, but there was odd thing what happened couple days after installation: I opened hood, and let car run at idle with ac on. I was wondering, what was the clatter sound what comes near ac compressor.

It was belt tensioner, belt was a little loose (little over marks), and tensioner was jumping up and down. Watched that a little time, and then suddenly i got huge "pssshhh" and fog coming out of compressor. It pulled out some refrigerant. I could not see, but i figure out, that it must have been compressor o-rings, from where the stuff did come.

I shut down engine, and called to my a/c mechanic. He asked to come and let him see it. In the way, i checked ac and it worked ok!

He checked pressures, and said, that they are ok (~3bar if i remember).
He also said, that pressures were okay, when we filled the system. He could not find any other explanation than overfill. He assume, that extra refrigerant did came out of system.

Now i have droven it few days, and ac works ok. I also have new, shorter belt, and tensioner is between the marks. But belt tensioner still jumps a little up and down, when ac is on. I'm not sure, but i think that it does not do it all the time (when we checked pressure, i remember that it didn't wobble at that time). Without ac it is like frozen in its place. Is it normal, caused by compressor load, or is there something still wrong with system?

 

You said your tensioner was stretched beyond the tension marks... So why would you not replace it?

 

I think it is not because of tensioner, but too long belt. Belt let tensioner go too loose. With new belt there is no that problem.

 

The compressor could be slugging liquid. 2.3 lbs of gas is way too much. The R12 fill is 2.25 lbs and you only need 80% of that with
R134. I'd recheck pressures aiming for a high side pressure that is 2.2 to 2.5 times the temperature of the air of the condensor.

 

Thats way too much for R134a.

 

Ok, thanks. My FSM says that AC Charge is 2 3/4. I assumed that it means 2.75lbs, so we filled 85% of it = 2,33lbs.

I think i understood FSM somehow wrong?

I must go and take some stuff out of there.

 

I did not understand, i'm stupid

Please, can you give me example, how to determine right pressure in the high side? I believe you use psi for pressure and fahrenheit for temps?
(Here in Finland we use bar and celsius)

How is the temp measured from condensor?

Of course my ac guy knows how to do this, but i want to clarify it to myself. And of course give him right specs.

 

FSM is wrong - Service Bulletin was issued to correct it. The sticker on the Blower Motor Housing should show the 2.25 lbs.

You measure air temp at the condensor with a digital thermometer or you can use the readout on the panel (if Electronic Air) since the sender is on the Radiator. Otherwise, it's about 10 degrees higher than ambient with a bottom feeder like the Vette. Pressures should be obtained at 1200 to 1500 rpms and the fan on (disconnect the fan switch on the high pressure line). Some shops will put a fan in front of it, but it doesn't do much good on a Vette.

 

This may sound a little off in left field, but I have seen a couple bolts come out of the back of the air pump which caused the air pump to tilt a little, so little that you would likely not even notice if someone did not show you. This will definately make the tensioner clatter. And yes replacing the belt will appear to fix the problem. If the air pump does finally get all the way loose, it will cause the alternator to tilt also, since the are connected by a bracket. After buying a alternator housing, front and rear alt bearings, alternator bracket, Rethreading air pump holes, ask me how i know.

 

Thanks for info, i must get it vacuumed and the recharged to correct amount. So, if temp reading in the panel is for example 77F degrees, right pressure should be between 170 and 192psi (2,2-2,5*77) ?? Did i get it right??


Great info, but
I have checked air pump brackets as well as alt bracket and water pump and steering pump. I have been dealing with strange issue; my original belt is too long. I'm not sure if it happened after compressor change or not. Original belt was 2270mm long, and now i'm using 2240mm, what seems to be ok. I really don't know what made the difference. Compressor pulley is same size than old one, and there is no other changes. It is of cource possible that belt has been long since i bought the car. I just noticed it due tensioner "clack clack" noise, what is caused by compressor. With new shorter belt, it makes no noise, but still wobbles up and down. Noise was generated when tensioner met it's limit.