AC folks........

[dannyvp]

My sons “new” 80series has an AC problem.
It doesn’t blow cold air.
So it’s been sitting a while before we got it. He dug a mouse and nest out of the air fan. The AC button light comes on some times (no rhyme or reason, to this that I can see) and the clutch doesn’t engage on the compressor. You can spin the clutch by hand when the truck Is not running.
im trying to determine if the compressor is bad or not. How can I tell?

 

[DiscoCam]

My sons “new” 80series has an AC problem.
It doesn’t blow cold air.
So it’s been sitting a while before we got it. He dug a mouse and nest out of the air fan. The AC button light comes on some times (no rhyme or reason, to this that I can see) and the clutch doesn’t engage on the compressor. You can spin the clutch by hand when the truck Is not running.
im trying to determine if the compressor is bad or not. How can I tell?

See if you can hotwire the clutch to turn on, then try to rotate it with the belt off.

Also with some compressors, they won't turn on if there is no refrigerant in the system.

Being a 3F-E it might still have R12 refrigerant in it. If it doesn't, maybe try adding an AC Pro can of R134a in it with a UV dye to see if there's a leak.
Not an AC expert here, but this would be my thought process on mine.

 

[dannyvp]

I’m wondering if someone has already added something to it. The port cover is not on it anymore. If they put 134 on top of the R12...it’s probably done for.

How can you check for refrigerant?

 

[Irish Reiver]

i would first check for refrigerant. Nothing will work if the system is low.

 

[DiscoCam]

I’m wondering if someone has already added something to it. The port cover is not on it anymore. If they put 134 on top of the R12...it’s probably done for.

How can you check for refrigerant?

The quick and dirty way is to take your key and press the high pressure shrader valve really quick to see if there's anything.

The proper way is to go to Harbor Freight and buy a set of manifold gauges and get a legit reading.

 

[flintknapper]

Get a set of manifold gauges (buy some, rent some, borrow some). ENGINE OFF: Hook up the high and low side (leave both valves in the closed position). Look at both gauges and tell us what the pressures are (should be even). Also note the ambient temperature (air temp) at the time of the reading.

What you will see is the 'static' pressure...which will tell us IF there is a enough pressure to satisfy the minimum requirement (about 30 psi) for your pressure switch (binary switch) to allow the clutch to engage.

IF the system is low....then there is no point in investigating further. Let us know what you find.

 

[dannyvp]

Get a set of manifold gauges (buy some, rent some, borrow some). ENGINE OFF: Hook up the high and low side (leave both valves in the closed position). Look at both gauges and tell us what the pressures are (should be even). Also note the ambient temperature (air temp) at the time of the reading.

What you will see is the 'static' pressure...which will tell us IF there is a enough pressure to satisfy the minimum requirement (about 30 psi) for your pressure switch (binary switch) to allow the clutch to engage.

IF the system is low....then there is no point in investigating further. Let us know what you find.

awesome, I’ll rent some tomorrow. Does it matter if they are R-12 or 134?

 

[flintknapper]

awesome, I’ll rent some tomorrow. Does it matter if they are R-12 or 134?

The gauges don't really matter at this point (R-12 and R134a pressures are very close) BUT the hose connections DO.

If you can post a picture of the service ports we can tell you whether your system is still set up for R12 or has been converted to take R134a

R134a ports are large and use a push on type connector. R12 are small and use a screw on connector.

So you'll need to have hoses with the proper connections or you won't be able to take the pressure readings.

 

[dannyvp]

 

[Rusty Marlin]

Start at step one, and work your way through. Easy Peasy lemon squeezy

Sanden A/C System Diagnosis (R-134a) - M.MOAM.INFO

Pin automotive air conditioner is a system which cools and dehumidifies the interior ofa car. bus or truck by removing h...

mafiadoc.com

 

[flintknapper]

View attachment 2364683

OMG....you have one of each. The upper port is a R134a 'adapter', it screws onto the former threaded port (like the one below it). So basically....we don't know what you have. My guess is that someone tried to do a conversion and installed only the low side adapter.

We don't know:

1. If the system was ever evacuated.
2. The system was ever flushed to remove the mineral oil (or other oil compatible with R12).
3. IF the system ever worked after the attempted conversion.

I'd be inclined to take a gamble and get two NEW R134a adapters, screw those on threaded fittings of the compressor so you can hook up your gauges. But...I suspect there is NO refrigerant in the system at this point.

IF that proves to be the case...you can add a single can (with dye) and see if the compressor will engage and where your leaks are or if the compressor is any good at all. It's a crap shoot at this point.

IF finances allow....I'd recommend replacing the whole system, too many unknowns to go chasing after, but worth an initial 'try' to get the compressor doing 'something' so we know one way or another.

 

[Rusty Marlin]

View attachment 2364683

That's an interesting mix, one 134a and one R12 fitting. Appears to have an R134a adapter on the Low side, but no adapter on the High side. So goodness knows what's going on inside. At the very least I'd do a full conversion to 134a fittings. Completely flush the system to remove the R12 compatible compressor oil. (Considering the mixed fittings I wouldn't trust that the last guy did the job correctly). Change the dryer, add the correct amount of PAG46 compressor oil, vacuum and fill with 134a.
But that's the least I would do. I'd probably sh!t can the whole system and start over. Its around $800 in parts and another $200 in tools and supplies.

 

[dannyvp]

I’ll get some adapters and gauges to at least see what’s going on.
with one of each port style, I would guess it wasn’t evacuated correctly.

 

[Lumpskie]

I’ll get some adapters and gauges to at least see what’s going on.
with one of each port style, I would guess it wasn’t evacuated correctly.

FWIW, I was in the same situation as you... no history and an empty system. For $200, a local mechanic cycled the system to evacuate any moisture, charged (with 134) and pressure tested my system. At that point, I was good to go. I

 

[dannyvp]

Ok I put new fittings on. Attached the gauges and it listed zero on both.
I added a little that I had left over to see what happened. This is what the gauges say now.
The compressor did kick on when turned on, I did not run it but a second though.

 

[flintknapper]

Ok I put new fittings on. Attached the gauges and it listed zero on both.
I added a little that I had left over to see what happened. This is what the gauges say now.
The compressor did kick on when turned on, I did not run it but a second though.View attachment 2365721

OK, are those the gauge readings with ENGINE OFF (static reading). Both sides hooked up?

Any idea how much (how many ounces) you put in?

A static reading 'should' be roughly equal on both the high and low side gauges (provided neither is blocked and the system has equalized). I see your low side indicating about 85 psi...but your high side shows zero.

Should look like this:

It's good that the compressor kicked in, that way we know the clutch works, your binary switch works and the electrical system calling for the compressor to kick in is good. BUT....we have a ways to go.

 

[dannyvp]

That was with the truck turned on. When the truck was off the low side showed around 95.
The high side has never shown anything.
I didn’t even put a can in, just a few squirts to see if it would hold pressure, bc both gauges were showing 0.
The can was one of those touch up cans that has a squeeze trigger on it.

 

[flintknapper]

That was with the truck turned on. When the truck was off the low side showed around 95.
The high side has never shown anything.
I didn’t even put a can in, just a few squirts to see if it would hold pressure, bc both gauges were showing 0.
The can was one of those touch up cans that has a squeeze trigger on it.

OK, gotcha.

I'd be tempted to put a full can in the system and then take readings. Don't let the compressor run too long (not more than a few minutes after charging with one 12 oz. can of R134a). We don't know how much oil is in the system is the reason for the short run time at this juncture. See what you get high and low side. I think you're just seeing a flash gas reading right now.

 

[dannyvp]

OK, gotcha.

I'd be tempted to put a full can in the system and then take readings. Don't let the compressor run too long (not more than a few minutes after charging with one 12 oz. can of R134a). We don't know how much oil is in the system is the reason for the short run time at this juncture. See what you get high and low side. I think you're just seeing a flash gas reading right now.

I have can of 134 but I don’t have a lid punch. I have to get another one. I do have some of the “fix a can” left over. It feel like it is a 1/3 full.

 

[flintknapper]

I have can of 134 but I don’t have a lid punch. I have to get another one. I do have some of the “fix a can” left over. It feel like it is a 1/3 full.

Just wait until you can get a can adapter to pierce the full can. No hurry. We will check back.