AC Learn and fix

Eveready said:

It would get up to about 50 on the low side and drop to 30 or so when the compressor came on

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That sounds about right, most cycling switches are set to shut off at ~25PSI. Some of them were adjustable, there's a small screw between the connectors on the switch if they are. If it were me, I'd try another can, slowly. I don't know what your ambient temps are but your low side should hold ~35 - 40 when running. Whe're already in the beginnings of summer here - right now my weather station shows 109*, ha ha.

PlayingWithTBI said:

That sounds about right, most cycling switches are set to shut off at ~25PSI. Some of them were adjustable, there's a small screw between the connectors on the switch if they are. If it were me, I'd try another can, slowly. I don't know what your ambient temps are but your low side should hold ~35 - 40 when running. Whe're already in the beginnings of summer here - right now my weather station shows 109*, ha ha.

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I might try to stuff one more can in it but I'm beginning to suspect something to be amiss. At least I won't be out much if it doesn't work. It does appear to be holding. I thought I might just get it pumped out, maybe flushed and that high side schrader valve replaced all at the same time. Then I would be better set to keep it going after all that is addressed.

I’m thinking, if you take it to the shop and have all that done, shouldn’t be a “need” for you to “keep it up.” At least, that’s my opinion!


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Bear 77 said:

I’m thinking, if you take it to the shop and have all that done, shouldn’t be a “need” for you to “keep it up.” At least, that’s my opinion!

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In a perfect world you would be right. Experience with old iron and especially converted AC systems tells me that most likely I will at least be adding some gas at the start of each season, which wouldn't bother me if it stays cool for the Summer. If you turn out to be correct I will revisit this thread and let you know.

One thing I learned in my study for my refrigerant license is that a compressor shaft seal that sits for 2 weeks or more is very likely to leak. My solution is to leave the ac on all year. In the winter I run ac with heat and it really doesn't do much but it keeps the seal oiled up.

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R422b said:

One thing I learned in my study for my refrigerant license is that a compressor shaft seal that sits for 2 weeks or more is very likely to leak. My solution is to leave the ac on all year. In the winter I run ac with heat and it really doesn't do much but it keeps the seal oiled up.

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Good point, I do that a fair amount in that when defrosting or "de fogging" using the compressor tends to speed the process no matter what time of year. Probably the real problem is that I don't use the truck except occasionally and it is definitely not a daily ride. I keep it as a toy, house pet and errand runner. I like having one to avoid putting building materials in my DD.

Well I do now have an update and it ain't gonna be cheap! After adding more Freon to no avail I took it in to a good service outfit and told them to go for it. I must say that temps in the 90's are a fine persuader to get the AC working. The blower had started squealing even on the high setting so I told them to go ahead and change that too as well as clean out the box.

I got a report today. The compressor and orfice tube were almost completely clogged with gunk. Most likely a PO had used the stop leak with Freon stuff to try and cure a leak and clogged it right up. Bottom line it is going to take a compressor, drier etc. Fairly big bucks. I will definitely have my 'two payments on a new truck" for this year but as I mentioned somewhere It will only hurt a little while and the AC will work.

I have about decided to continue making the truck comfortable and search out some good seats for it . I have carpet and headliner ready to install so with the AC done I may get after it. It is a really solid and essentially rust free truck with a good motor and transmission. I think it will be worth it.

Just got it back today. It was nice and cool on the way home and cycle time seems about right. Air is "cool" but not really cold in my opinion. When I got it home I put a thermometer in it. Outdoor temps were around 85 or so and air was blowing at about 55, which is certainly cool enough but not as cold as my other cars. I am wondering if I shouldn't try to stuff one more can of refrigerant in it depending on current pressures. What do you guys think? Should i just take it back to the service place and ask or just drive it and see if it changes.

Obviously if it is leaking I will know soon.

Eveready said:

Just got it back today. It was nice and cool on the way home and cycle time seems about right. Air is "cool" but not really cold in my opinion. When I got it home I put a thermometer in it. Outdoor temps were around 85 or so and air was blowing at about 55, which is certainly cool enough but not as cold as my other cars. I am wondering if I shouldn't try to stuff one more can of refrigerant in it depending on current pressures. What do you guys think? Should i just take it back to the service place and ask or just drive it and see if it changes.

Obviously if it is leaking I will know soon.

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If they are worth their salt don't mess with the charge the temp is probably being controlled by the compressor cycling switch. Some cars will blow 38° and some blow 50° I consider it normal variation. If the accumulator is un insulated or poorly insulated you may try wrapping it in foam tape or something. You might should talk to the shop they might have some suggestions. Maby a new cycling switch would pull it down lower.
If you have a guage set put on the low side guage and let us know what pressure it cycles at.

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I've been DDing it the last few days just to make sure all is right with the AC. Drove it on an errand today and before I shut it down when I got home I got this picture of a most beautiful sight! I am SO happy to have AC in the truck again!