66ca

I thought I was about ready to have some nice cold ac but I guess I have yet another problem that I don’t know what it is.

When I got the car, the whole system was intact, but empty. Before I started anything I started the car and jumped the low pressure switch to see if the clutch would engage and it did. I assumed it was ok.

I took everything apart and flushed all the lines. I replaced the orifice tube and the accumulator. I replaced the o rings. I put about 7 oz of ester oil in the compressor and buttoned it back up.
I pulled a vacuum on it for at least an hour and it pulled it down really good. Then let it set an hour and it never lost anything.
I started the car with ac on, hooked up a can of 134a and started putting it in. It took forever for the clutch to ever come on, and all it ever did was click on and off. It took a little out of the can, but not enough to do anything.
After watching it for a bit, the clutch only clicking in and out I shut everything down.
And to top it off, when I disconnected the line from the low side port, “air” was leaking past it....like past the schrader valve.

So, is the compressor bad?
And why is the low port leaking out?

BLUE1972

IF IT'S COMMING OUT OF THE SHRADER VALVE YOU ARE LEAKING. That valve should not leak.

If you pulled a vacuum then you need about 2.5 cans to fill the system.

66ca

But after pulling vacuum it wouldn’t take the Freon
the clutch just kept cycling on and off

and I’m not sure why that low port would be leaking unless I got it too tight

interpon

Well fix the low port valve..pull vacuum try again..

its also probably why the can didn’t go in well either, the valve that is..

know how many ounces go in system..i Thought r134a should only be about 80% of r12.

that first can at vacuum should go in fast

also what are gauges telling you?

66ca

Interpon
ok I’ll give that a try.
What do you think it could be with that low side port? I took the old schrader valve out before I put the retro fit piece on. There shouldn’t be anything inside there other than the new schrader.

interpon

Change the new valve?
i think they sell those retro kit adapters for like 10 bucks at any auto store..

gotta fix the leak..vacuum may not show it...but i would still try...luckily r134 is about 4. Bucks a can at walmart. I am going r12 and s leak would be expensive for me..

are you using gauges?
make sure its pure 134 as you already added oil...i think with ester you could go either way...

66ca

That’s what I meant to say.
Im thinking it’s the low port of the retro kit. I installed the retro kit yesterday. Everything was good when I pulled the vacuum.
Its making me think there is something wrong with the shrader valve inside the low port adapter. I say that because that’s where it was leaking from when I took the low side connector off, and the Freon wouldn’t really go in.
So wouldn’t that seem that could be the problem? Maybe a faulty shrader valve?
im not sure if they are supposed to be screwed in all the way or a certain amount, I didn’t mess with that Mary of it. I just screwed on the entire retro attachment.
I was thinking I would just buy another retro kit and swap out the low side

66ca

Yes I am using the gauges too. And it’s just straight 134a. No oil additive

REELAV8R

vacuum it down from the high side port. Then then add first can or most of it before you start the car.

vacuuming down on the low side can be problematic due to the reed valves in the pump.

of course the shrader needs to seal for any of this to work.

interpon

Or both high and low vacuum.
op using gauges?

BLUE1972

The Schrader valve is a tire valve, if it leaks then you get a flat, in the A/C case Freon leaks out - no charge = no A/C.

The retro kit I used a long time ago required the original valve to be working properly. I wound up fixing the original valve and then a retro kit was added.

I agree = vacuum from both sides of the A/C unit, If the Freon is not going in then the valve is bad.

To save money you can charge the system with 20# of air (no higher in pressure) , don't run the system and listen / soap joints - parts to see if there is a leak. Then pull a vacuum for 45 to 75 minutes.

The valve may leak under pressure but not vacuum. Thus the Freon escapes …

66ca

Ok here’s what’s going on

I replaced the low side retro fit port with a new one.
Pull a vacuum for 1 hour and shut everything off and let it sit for an hour and it didn’t budge on either vacuum gauge.
So I decided to put Freon in it. It took forever for the first can to start going in and turn on the clutch. After a can and a half, the compressor continually cycles the clutch in and out. The low side hose never got the least bit cold and the high side line never got at all hot.
This pic was taken after a can and a half with the car running and ac still on. Low side was jumping back and forth between 25 and 35 and the high side guage would drop a little from where it is in the picture and back up.
Does this mean the compressor is bad? If it was circulating like it’s supposed to wouldn’t one of the lines gotten somewhat cold?


on the the plus side, the new fitting with new shrader valve didn’t leaks when I removed the couplings

interpon

Add the amount for your system..or rather 80% of what r12 says it needs..
if it says 3 pounds r12 put in about 80 percent...or if it was me until high side was at least 200..
a can and a half....assuming 12 ounces...isn’t much

I also sometimes gently shake can..if the can it cold its going in.
i also sometimes use warm water and put can in it..or the bottom 2/3...

you should at least reference your capacity and or pressures at temperature humidity as they will vary...

66ca

It’s 93 here today with a heat index of 105

i will put another 2 12oz cans in it. Which will take to actually about 3 1/3 cans. I don’t think that partial can was half full

interpon

Strictly i wild guess but at that temp..230 high side?...low side running 35 ish?

chevymans 77

First 7 oz of oil in the compressor is a lot of oil for the compressor, usually the entire system holds around 7 to 8 oz. You should put 4 oz in the compressor if its empty (should follow the manufacturers suggested dose) and spread the rest of the oil through the major components of the system, accumulator, condenser, evaporator. Once oil is placed into the compressor you should turn it by hand to distribute the oil within the compressor, never turn it on without turning by hand if oil is added specifically to the compressor. The oil is now trying to find its place within the system so you need to give it some time.

Its very hard to diagnose a compressor with the conditions your seeing right now, the pressures don't appear to be to far outside of a functioning system.

High side pressure is a little low but its still a little low on charge, the clutch cycling is whats driving the pressure to cycle on the low side. If the system was designed for 36oz of r12 the you need to add a little over 2 12oz cans of 134a (need to verify how much r12 is recommended so you ca figure out how much 134a to use)

I would add a little more 134a a little at a time until the suction line to the compressor starts to cool down.

Is the system still factory, what year car are you working on?

66ca

I got a little over 2.5 12oz cans and the compressor is staying on like it’s supposed to.
Not sure if it’s where it needs to be but I stopped the flow of Freon when the low side was around 40 and the high side around 250. Is this about where I need to be?
it seemed like I saw something that said low side 35-45 and height side 275

66ca

The coolest it gets is about 65 sitting idling. I’m thinking it would get colder going down the road.
Not sure if this will matter, but my temp selection slider doesn’t go all the way completely to the left in the blue. It gets within less than a quarter of an inch and feels like it’s binding somewhere in the cable

blk79nj

There should be a shut off valve to stop the flow of coolant to the heater core. Make sure that is functioning properly, because the heat from the heater core may be "fighting" coldness from the evaporator.

i put a manual shut off valve in my car.

interpon

Well its running and virtually no airflow across condenser...and over about 28 degrees cooler..
not there yet...again doyouknow what capacity is? I would add 80% of that...and watch gauges for freak...

agree with comment on that heater shut off..my 79 i can see behind glove box it needs to hit that switch to stop water...
so having slight gap to left makes sense as you want it to push that switch