Caincando1

My truck was equiped with A/C but it doesn't work. I would imagine it need to be recharged. Anyone ever do this, or have it done?

edwinsmith

Assuming your hoses and such are in decent shape and it still has at least a tiny amount of pressure in it, you can probably just recharge it yourself. Just go down and buy a charge hose kit and a few cans or R134a. There should be adequate instructions with the charge hose kit. You might want to add a can of PAG oil first in case it originally had R12. The new PAG oil mixes with the old oil just fine and make it compatible with R134a.

The kit I got has a cheap gauge with it to see if you have the correct amount of refrigerant if you don't have a sight glass. If you DO have a sight glass which I believe you do just keep adding refrigerant untill the bubbles disappear then stop. If you overcharge it you could damage things.

You'll need to jumper the low pressure switch to get the compressor to engage though if it's way low which is probably why it doesn't do anything. The switch is located up near the top of the firewall on the passengers side. Just pop off the connector and put a jumper wire across the terminals of the connector (not the switch) and then turn the A/C on and start the engine. If it blows any cool air at all then it's just low and you're in luck.

On mine the compressor is locked so watch for that when you jumper the switch or it will burn the clutch out quick!

If your compressor is bad or you got a bad leak then you need professional help.

Edwin

Caincando1

Thanks! I have no idea if the compressor works or not. From what I've seen the refrigerent isn't very expensive, so I guess I'm not out much if it doesn't work.

edwinsmith

See my edit.

flashgordon

Mine had to be re charged every year! found oil(leak) on the lower right had side of the condencer, replaced the condencer and charged system and hopfuly i wont have to charge it next year.

Underpsi

when I had my a/c replaced All the fittings had to be changed to the new systems

edwinsmith

You can buy a conversion kit to change from R12 to R134a. Has adapters to screw on to the old style charge fittings. It also has new seals and O-rings if you want to go that far into it. On my car I just added one of the charge fittings on the low side, added the PAG oil and charged it up. Every year I have to add a couple of cans of R134a but I've extended the life of my system a lot for not much money. But the car has just short of 200K miles and just won't die.

MoparMarv

Well I'm in the same boat. My truck that I just got has A/C that doesn't work. I have been meaning ask if people have converted to 134a and how it works in the system. I did my honda a few years ago and it worked good on the 134. If the system has no R-12 in it and is dry you should really change the drier as the dessicant will no longer be good anymore. In addtion the older desicants are not compatable with the 134a and they can come apart and go thru out the system. Also look into the Oils they have PAG and POE. From what I remember when I got my A/C training and cert the PAG oil will mix with the old mineral oil in the system and settle to the low spots and the 134 can't carry it causing a lack of lubracation of the compressor. I think for conversion POE(ester)was recommended because it didn't mix with the old mineral oil and was able to be carried thru the system. Look around though because it has been a few years since I looked around in the conversion. When i did the honda years back I had to change a few things so I took as much as i could off and flushed the lines and drained the compressor of all the old oil. Some systems take the 134 better than others. I have seen people just put the stuff in and go for a few years with no trouble and I have seen people put it in and the compressor devolpes the black death in a few weeks. If your going to do it do it smart and it should treat you fine. I had a good site that answered alot of questions about the conversion if i can find it I'll put up the link.

edwinsmith

OK, I think I made a mistake on the oil. It says it is "Premium synthetic polyolester lubricant" "Compatible with R-12 & R-134a refrigerant".

It came with the adapter and seal kit but all I needed was the adapter for the low pressure side. (DO NOT CONNECT YOUR CAN TO THE HIGH PRESSURE SIDE) Since it was a bottle of liquid and I didn't want to open my system up which would require vacuuming down again, I got the oil in the charge can so it could be injected under pressure of a bit of refrigerant.

As long as your system still has at least SOME pressure in it you shouldn't need to worry about your dryer being contaminated. There are no guarantees however but I like to try cheap first.

My car had been running for 5 years and just leaks a bit.

Edwin

jughead

i would recomend estor oil it is more compatable with the old style hoses. mine has been done for 4 years with no problems. just be sure to flush the system with a kit that is available from most parts stores.

searcher

I just fixed the ac on my '89. The PO said that he had the ac redone with a new compressor last year but that he didn't change the clutch and the clutch was now gone. Well it costs almost as much for the clutch as it does for the compressor assembly. I ordered a rebuilt assembly from Advance website at about 250 bucks (this one they couldn't get at their local stores). New is better but on the Cummins they are just too much. The charge on my system was gone. I replaced the evaporator with a used one from the U Pull It. I was actualy changing the heater case. The guy that fixed the ac before wanted to clean the evaporator so he cut a hole in the case as opposed to a days work pulling the case. I looked at the evaporator and it really looked bad from water and debris. The one at the U Pull It looked like new and since I already had it out... If you do this then try to find one that is aftermarket. The original one they used in our trucks were garbage according to the local ac folks. A new dryer and H valve from Advance were installed. Not bad at less than 40 bucks. I've paid more than that for dryers alone for other cars. I installed filters on both the high and low side to protect the compressor. Dodge says that our trucks can't be converted to 134. I guess it is because of the smaller than normal condenser. There just isn't enough surface area to allow the transfer of heat from the refrigerant to the outside air, hense the reason why 134 is not as good a refrigerant as R12. 134 seamed to be cooling the cab as I filled the system, but I think that I overcharged it maybe. I took the vehicle for a drive and when I returned it wasn't cooling. I checked and the low side hose was frozen from the filter to the compressor. Either the filter I bought had an orifice built into it or it pluged and acted like an orifice. I checked the pressure and had 80psi on the low side (semi liquid at the evaperator) I removed the low side filter and spliced the hose. Recharged with freeze12. System is working fine. I don't understand why the filter had a problem. There was no orifice in it and no sign of trash. I wish you luck on adding freon and getting back on the road. We did it on my neighbours gasser and he is still cooling after a month. I've never been that lucky. If you think the dryer is saturated then no amount of freon will fix it and you will actually do more damage. Dodge says to use pag oil for the system. Freeze 12 says use ester oil. 134 will accept either oil so Pag oil is fine. I used ester oil without a problem. The difference in freeze12 and 134 is that freeze12 works at a lower pressure than 134. Our systems have a hard time compressing 134 to a liquid (required in order to give off the heat it collected as it passes thru the condenser). Freeze12 works at a lower pressure than R12 did. Less load on the compressor. Problem is that the mollecular structure of freeze 12 causes it to leak thru a hose that would hold R12 without leaking.

jughead

they say 134 wont work in our trucks but mine has had it for 4 years and will do 38 degree air on a 90 degree day. it works better than 3 company 00 ford trucks with factory 134.

mhuppertz

You are lucky. The head pressure has to be much higher for 134a. They overcharged my 134a conversion to get it colder and it pulsed so hard it ripped the accumulator off of the fenderwell (where it still hangs today ). Mine definately doesn't work as well as the good old R12. If I had to do it over again, I'd use this http://www.refrigerantsales.com/products.html

I still might!

edwinsmith

Actually the opposite is true. The pressure needs to be LOWER for R134a to cool as well. If they put in more thinking it would cool better then that's why your's doesn't get cold.

Let some out and it will improve.

Only when you don't have enough to get all liquid to the expansion valve does it stop cooling as well. Overcharging will definately damage things as you discovered.

Edwin

mhuppertz

Guess I read wrong. I even talked to a refrige guy who told me the head pressure was higher with 134a.... Hmmmmmm

I'm game to let some out just in case .

Thanks Edwin, I'll do some more checking, and sorry to all if I had it wrong!