AC help needed please

[FuzzFace2]

Ok my 81 F100 that has factory AC (HVAC box & controls) (late compressor with vbelt used junk yard 1 years now)) has stopped working. The compressor has made noise from day 1 but has worked.

The evap is from the parts truck and was working till the roll over. System had psi on it till I pulled it apart.

Hoses are also new other than from condenser to orifice valve, new dryer & valve when I got the system running a year ago.

This last go around the compressor would kick on & off like low on charge and I seen because of dye in the system a leak at a fitting I did not touch or change the o-ring. The system has lost charge other times because of loose fittings but will not say from who

The last few times I just tighten the fittings and added more charge but each time did not blow as cold as the time before but figured I needed to pull a good vacuum before the next fix.

Well I replaced the leaking o-ring, it was a black one to factory.

Looked for any other leaks at all the fittings, none showed up.

I pulled the orifice valve to see if it had any junk, it was clean but ........

When I pulled the valve out there was pressure on the evap side?

I had the system open at the low side of the compressor so I would think the system would not of had any psi on it? A lot of oil & dye came out when it came out.

Cleaned up the mess, checked the o-rings and put the system back together.

I pulled vacuum for 30 mins to 29 hg.

Let the system sit for 30 to 45 mins with pump off.

It dropped to 28 hg and just figured system evened out.

Changed the pump oil and pulled vacuum for little more than and hour down to 29 hg.

Now this is where I think the issue starts?

Start the motor, AC on MAX, fan high.

Go to add 1 small can and I dont see anything going through the sight glass on the gauge set and the gauges dont really move till I shake the can. Can gets cooler as dose the hose.

The PSI comes up enough to have the compressor start but stops when the psi drops, normal to me at this point (kind of) but think the can should have gone in and the PSI should have come up to run the compressor.

I jump out the PSI switch, compressor runs all the time but the gauges dont really change much?

I can see the line after the orifice valve gets ice on it but no cool air out the vents and the dryer is hot where I think it should be a little cool.

I add a 2nd small can and the pSI comes up some but still not to the point of running the compressor all the time, kicks on & off. and making noise like it always has, kind of a clicking noise.

Compressor not running I get L/H 100 / 100

Compressor running motor at high idle (1200 rpm) L/H 11 / 155

Compressor running motor at idle (800 rpm) L/H 20 / 155

Compressor will stay running at the 800 rpm idle but when you up the rpm it kicks on & off.

I also bypassed the gauge set and used one of them short hoses with a gauge on the 2nd can. That gauge shows over PSI?

I am thinking a bad compressor but with pressure on the system when I pulled the orifice valve I am not so sure?

The system has factory service valve at the compressor and thinking I could close them, remove the old compressor, if it is bad. Install new compressor and open valves and be ok what you think?

Is it the junk yard compressor and could I swap it the way I posted?

I am almost to the point of giving it to a shop and have them fix it as I am tired of messing with it.

Thanks for any help

Dave ----

[mat in tn]

first of all, what orifice tube is in it?

[FuzzFace2]

first of all, what orifice tube is in it?

Blue and what the factory had in it with R12.

Now I have had this system blowing cold with the blue valve when I first got the system working so I dont think its the blue orifice valve.

I have also seen post between the blue or red and most go back to the blue as it blows colder.

Again it worked before when the OAT has been in the upper 90's so I cant see it being the problem.

Besides the loose fittings and needing a recharge each time it has blown warmer and warmer each time.

I was thinking it needed a good vacuum pulled but now I wonder if the compressor has been going south this whole time? I know the noise is not normal but it worked so I did not look into it deeper.

Dave ----

[grumpin]

first of all, what orifice tube is in it?

Blue and what the factory had in it with R12.

Now I have had this system blowing cold with the blue valve when I first got the system working so I dont think its the blue orifice valve.

I have also seen post between the blue or red and most go back to the blue as it blows colder.

Again it worked before when the OAT has been in the upper 90's so I cant see it being the problem.

Besides the loose fittings and needing a recharge each time it has blown warmer and warmer each time.

I was thinking it needed a good vacuum pulled but now I wonder if the compressor has been going south this whole time? I know the noise is not normal but it worked so I did not look into it deeper.

Dave ----

Something I learned to do is use a bucket of warm water to put the can in to get it to empty as much as possible.

Not hot water, but warm, lukewarm or slightly more so.

Are the high and low pressures different? If high and low are close in pressure, usually a sign of a bad compressor.

[FuzzFace2]

Something I learned to do is use a bucket of warm water to put the can in to get it to empty as much as possible.

Not hot water, but warm, lukewarm or slightly more so.

Are the high and low pressures different? If high and low are close in pressure, usually a sign of a bad compressor.

I know of the water trick but it was like it was not being pulled or sucked in to the system.

I did set the cans on the intake / exh manifolds, 300 six so they are right there, that was warm and did not really help like it has in the past.

1200 RPM the low side was 11 / high 155

800 RPM low 20 / high 155

Compressor off both sides 100 / 100

What was strange is when I used the can hose with gauge on the low side of the system, the gauge said the PSI was to high / in the red?

But the compressor would not stay running unless I jumped the switch.

Other than the difference in PSI with the change in idle RPM only the low side changed not the high side.

Its like it would pull a little but did not put out any psi noted at the 155 psi at the 2 different idle RPM's

Dave ----

[grumpin]

Something I learned to do is use a bucket of warm water to put the can in to get it to empty as much as possible.

Not hot water, but warm, lukewarm or slightly more so.

Are the high and low pressures different? If high and low are close in pressure, usually a sign of a bad compressor.

I know of the water trick but it was like it was not being pulled or sucked in to the system.

I did set the cans on the intake / exh manifolds, 300 six so they are right there, that was warm and did not really help like it has in the past.

1200 RPM the low side was 11 / high 155

800 RPM low 20 / high 155

Compressor off both sides 100 / 100

What was strange is when I used the can hose with gauge on the low side of the system, the gauge said the PSI was to high / in the red?

But the compressor would not stay running unless I jumped the switch.

Other than the difference in PSI with the change in idle RPM only the low side changed not the high side.

Its like it would pull a little but did not put out any psi noted at the 155 psi at the 2 different idle RPM's

Dave ----

Looks like it’s pumping. Odd that it’s not pulling it in.

I’ve had to leave the switch jumpered for 3 or more cans on bigger systems.

[85lebaront2]

Looks like it’s pumping. Odd that it’s not pulling it in.

I’ve had to leave the switch jumpered for 3 or more cans on bigger systems.

I have had the rubber seals where the hoses attach to the ports actually block the flow either due to swelling or squashing when attached. Darn near drove me crazy till I figured it out.

[FuzzFace2]

Looks like it’s pumping. Odd that it’s not pulling it in.

I’ve had to leave the switch jumpered for 3 or more cans on bigger systems.

But this system is not that big and other times I have charged it it took the cans. This time just seams strange the way it is charging?

I do have 2 more small cans and some still left in the 2 that I used that I will have to heat to get the rest out.

I have had the rubber seals where the hoses attach to the ports actually block the flow either due to swelling or squashing when attached. Darn near drove me crazy till I figured it out.

At first I thought it was the gauge set that I was using to add the first can through and why the 2nd can I used a short hose that hooks to the can and has a gauge with colors, no psi readings.

I forget when it would go into the red, if when adding or resting?

But what you say I wonder if the 134a to R12 fitting adapter could be the issue?

If it was plugged / blocking like you say then the cans would not be pulled into the system like it should.

Then again the gauge set was getting readings so I would think it is ok.

Why do you think the high side stayed at 155 psi but the low side changed with RPM 11@1200 rpm / 20@800 rpm?

Dave ----

[85lebaront2]

Looks like it’s pumping. Odd that it’s not pulling it in.

I’ve had to leave the switch jumpered for 3 or more cans on bigger systems.

But this system is not that big and other times I have charged it it took the cans. This time just seams strange the way it is charging?

I do have 2 more small cans and some still left in the 2 that I used that I will have to heat to get the rest out.

I have had the rubber seals where the hoses attach to the ports actually block the flow either due to swelling or squashing when attached. Darn near drove me crazy till I figured it out.

At first I thought it was the gauge set that I was using to add the first can through and why the 2nd can I used a short hose that hooks to the can and has a gauge with colors, no psi readings.

I forget when it would go into the red, if when adding or resting?

But what you say I wonder if the 134a to R12 fitting adapter could be the issue?

If it was plugged / blocking like you say then the cans would not be pulled into the system like it should.

Then again the gauge set was getting readings so I would think it is ok.

Why do you think the high side stayed at 155 psi but the low side changed with RPM 11@1200 rpm / 20@800 rpm?

Dave ----

Usually with that big a difference something is restricting the flow, but, if you are still getting gas through to the orifice tube it can give strange results. Does your system have one of the quick connect fittings in the liquid line from the condenser? I have seen these come apart internally and partially block the line.

[mat in tn]

Usually with that big a difference something is restricting the flow, but, if you are still getting gas through to the orifice tube it can give strange results. Does your system have one of the quick connect fittings in the liquid line from the condenser? I have seen these come apart internally and partially block the line.

this is why I was asking. it is behaving as though it has a clogged orifice tube. the compressor creates differential, yet the orifice regulates it. I'm more concerned of this due to you saying earlier that there was contained pressure in the evaporator after evacuation and it was released upon removal of the orifice tube. sure sign of a stuck tube and I certainly hope you did not reinstall the same one. if you did then that would explain the system not drawing from the can.