AC Question

[TheCougarine]

Hey guys, so I recently had my ac compressor go out and had my mechanic replace it and he said he converted it over to r134. Well its not cooled right since and I got to looking it over and what I understand to be the low pressure port on the passenger side is still an r12 port and the only r134 port is the one right above the compressor. So I'm wondering if this work was done correctly or does this seem weird to y'all as well? I've always been under the impression that the ac on the trucks was recharged at the port on the far passenger side not on top of the compressor and regardless shouldn't all of these ports be switched if it was converted? I'm wondering if this might be part of my problem since I had nice cold ac before the compressor went out. Was this work just not done correctly or am I missing something? Thanks in advance.

[prodjay10]

It's hard to say if it was done right or not. I've heard some people say that r134a in an r12 system will never cool enough and others say that it can be done right, you have to replace and add the right parts and play with the amount of refrigerant until it's cooling just right.

Personally, I've never seen a converted system cool as well as one with the right refrigerant.

[TheCougarine]

Yea the all the right parts part is what's concerning me. I'm mostly curious as to why the system still seems to have an r12 fitting on it and if that's a normal thing. I always thought you charged ac through the low pressure port and that seems to be the one that's still r12
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[prodjay10]

I've heard of some AC guys charging on the high side. Not sure why.

[Bigdav160]

You charge from the high side if you don't want (non compressible) Liquid getting into the intake of your compressor. Normally you wouldn't be doing this with small cans.

I think the consensus is these trucks are not good performers with R134a. The condenser is way too small, the compressor seals leak it out, the POA set point is wrong and then you have the issue with non barrier hoses deteriorating with PAG oil. (ester oil might be OK)

[TheCougarine]

Thanks guys that's the info I was looking for.

[TheCougarine]

Update: Talked to my mechanic and all he did was fill it up with r134. What all needs to be changed for r134 to actual cool at all? Apparently just filling the system up with r134 isn't going cut it. Any advice?

[engineer_gregh]

The system should have been throughly flushed, vacuumed, filled with the correct oil for 134a, and the POA valve adjusted for the increased pressure as a minimum. I have two that have been converted, one with a modern condenser and one with the original. The one with the newer condenser is colder. I'm not an A/C expert but done a lot of reading on the subject. I'm sure others will chime in with their experience as well.

[F.A.A.benny]

Originally Posted by engineer_gregh

The system should have been throughly flushed, vacuumed, filled with the correct oil for 134a, and the POA valve adjusted for the increased pressure as a minimum. I have two that have been converted, one with a modern condenser and one with the original. The one with the newer condenser is colder. I'm not an A/C expert but done a lot of reading on the subject. I'm sure others will chime in with their experience as well.

This is correct. it would need the poa valve recalibrated and a parallel flow condenser, and I change the drier. If you not flushing then drain the oil in the compressor and use eater oil as it is compatible with both refrigerants. Personally I would go back to r12 as its really not that expansive and with a lot less work since your system was working fine with it. You can find r12 on CL or on ebay

[davepl]

I have no changes from stock other than a parallel-flow condenser, and when it's not leaking it blows fairly cold air. It was converted before I got the truck, so I'm only assuming the POA valve was adjusted properly.

[truckdude239]

Originally Posted by Bigdav160

You charge from the high side if you don't want (non compressible) Liquid getting into the intake of your compressor. Normally you wouldn't be doing this with small cans.

I think the consensus is these trucks are not good performers with R134a. The condenser is way too small, the compressor seals leak it out, the POA set point is wrong and then you have the issue with non barrier hoses deteriorating with PAG oil. (ester oil might be OK)

Not totally true , i was taught to alway charge though the low side, not sure why but it was on my ase cert test to charge though the low

[Bigdav160]

All my machines charge through the high side as a default.

I can change it to low or both.

[TheCougarine]

I mentioned switching back to r12 and he acted like that was impossible to do and got upset that'd I mentioned it even though he'd charged the old system before with r12 so go figure there. At this point I don't think I'll be taking the truck back him. What do you guys think would be my best choice going forward since the things already full of r134