88 B2200 A/C question

When I got this truck from my sister I was told the a/c didn't work. I figured I'd take a chance and get some 134a and charge it up. Followed the directions on the can...start the truck, let it run for 3 min then check the pressure. Well I started the truck and pushed the a/c button..."Click" goes the compressor clutch. Whoa...it works??! I guess it wasn't broken after all. The air is somewhat cool but nowhere near as another car I have. I'm not complaining...any cool is good but what would cause it to not be as cool as the other vehicle? Are there certain parts that degrade the system's ability to cool? I don't know that much about A/C so any help would be appreciated. The truck was converted from R12 years ago to 134a.

Thanks in advance!

Different cars have different A/C's would be my bet.
A proper purge/charge would probably bring about some more AC power
Clean the condenser if you can, might be full of crud (exterior), if in doubt leave it be though
In the meantime, WOOHOO! Cool air!! good job

I always forget the condenser. Good idea! Thanks!

I cant believe it worked. that NEVER, NEVER happens!!!!!

Wood - don't want to break your bubble, but this won't work. If adding R134a helped, then you had (have) a leak. I hope you only added R134a and not one with a leak sealer or conditioner; only refrigerant, correct oil, and (optional) UV dye belong in an AC system.

For continued operation, and best performance, you need to find the source of the leak, fix that, then evacuate properly and add correct amount of refrigerant by weight.

If the system was essentially "empty" before you did this, then it was filled with air, and air contains moisture. So likely its receiver-drier is toast. And if the system wasn't evacuated before you added refrigerant, than you have air in the system and performance won't be optimum.

Your best case scenario is that there still was a little refrigerant in the system, so no air got in. But you still need to fix the leak (wouldn't have been low without a leak, refrigerant is not a consumable), then evacuate and charge with refrigerant correctly.

The Cuss lives in Arizona, and good AC is an absolute necessity here, over 110F here lately.

Cusser,

I did add freon but the a/c worked before I added it. I only added it to top it off because it wasn't that cold. (it's been in the 100's here too) I used the 134 in a can with the gauge and all from Oriley. It says on the can that it contains oil and dye.

What should I do? Should I take it to have it evacuated and refilled?

It's cool...but not cold by any means. I remember when it had the R12 system on it, it would blow frost out the vents.

Thanks for the help!

OK, from what you told me so far: all is good. But there is a leak, may be small, or it wouldn't have been low on refrigerant, and adding refrigerant would not have helped. So since you added dye, use a UV light and yellow glasses to look for fluorescence on fittings, hoses, compressor seal, etc. while it's dark. Also check the evaporator condensate rubber drain tube with the UV light. Or take to a real auto AC place (not a brake place or jiffy lube) to get the leak fixed and the system then adjusted to correct R134a level.

If you do see dye residue at a fitting, tighten a little, or replace O-ring if there is one (refrigeration O-ring only). AutoZone or O'Reilly should have loaner gauge sets for R134a, borrow one. Wear protective goggles, and read the pressures at about 2000 rpm with AC running. Typical pressures should be about 30psi on low and about 250-300 psi on high side. If high side reads lower than that, add 1/2 can R134a and again read pressures.

The best, and only "real" way is to evacuate all the refrigerant and add the correct amount by weight. But pressure readings may get you "there". If you don't fix the leak, technically illegal to charge a system. But you'll continue to have issues until the leak part is fixed.

Good luck.

Thanks Cusser...I'll give it a shot.

Could my old, failed resistor have caused the A/C to not work? After I replaced it I had all 4 fan speeds instead of just the top two. I wasn't sure if it would make the A/C work or not though.

Yes, the blower resistor is involved in the AC compressor operation.

See

What happens if you recharge with 134a, mines probally has r12 in it still, Ive read it could

Sorry this got a little long......... but I bet you'll get over it.....


Hey guys....This is right up my alley... I am a HVAC/R technician for a living. First off, I have to vent a little about the whole issue of r-134a refrigerant. It is a HORRIBLE refrigerant (for several reasons) when it comes down to the actual properties of the refrigerant itself. They three biggest reasons that it is a horrible replacement for a r-12 system is:

1) Because of the properties of r-134a it requires a different type of oil in the system to operate correctly. All types of refrigerant "carry" oil molecules with them when they "travel" around the system. R-134a will not "carry" the mineral based oils that were used in the original r-12 system, therefore in order to CORRECTLY convert a r-12 system to r-134a the oil must be replaced to keep the compressor from failing. The majority of the time this is not done, especially at the "cheaper" repair shops, or by the car owner if they are doing it them self. If the oil change is not done it typically takes a couple of years and then the compressor fails.

2) R-134a is a fairly good "cleaner". It will flush any lodged material from the system and makes it start floating around. Hopefully the drier/filter will catch it... Also r-134a was not designed to run in a r-12 system and the rubber hoses and o-rings get eaten away. R-134a "eats" standard rubber (if you say that the system was converted a couple of years ago, this may be the case, also the other prone area of leakage is the compressor shaft seal). A system that was designed to operate on r-134a has different hoses, gaskets and o-rings that can take the abuse. That is why Cusser said to use a o-ring that is designed for refrigerant and not just "any-old-o-ring".

3) R-134a is a horrible "drop-in" replacement for r-12 because of the density of the gas itself. R-134a is much less dense and therefore IT WILL NEVER COOL AS GOOD AS THE ORIGINAL R-12 DID!! Think of it this way. The r-12 compressor has a pre-determined set displacement. Meaning that for each rotation of the compressor it is supposed to pump a certain amount of r-12. Well since the r-134a is less dense it cannot pump as much as it is supposed to, therefore giving you less cooling. (Kinda like running E-30 or E-85 ethanol fuel in a older gas engine ((lets leave the fact alone that it would hurt the fuel pump and engine if the engine was not designed to run these fuels)). You get horrible fuel economy because there is less "power" in the fuel and you have to have the accelerator pushed down more to get the same horsepower out of the engine.) That being said if you were to spin the compressor faster you could get better cooling, but you cannot easily find a smaller pulley. Now don't get me wrong, if the system is designed from the factory to operated on r-134a it will operate fine. It just isn't a good replacement in a system that was designed for r-12.

The reason that the car manufactures use r-134a refrigerant is because it is what we call a hydroflorcarbon or HFC. R134a is a single HFC compound. No chlorine content, therefore no ozone depletion potential. I am sure that most of you have heard of the chlorofluorocarbon or CFC? R-12 is a CFC. The difference between the two is the chlorine molecule. They think (they have not proven) that the chlorine molecule is what is causing the ozone layer to shrink. So the reason that they use r-134a is because one of the biggest freon consumers was the auto industry. Think of how many people just cut the lines.....and let it blow out. Or think of every time there is a front end car collision. Or think of how many times people just top-off a system and don't find the leak. That is why they use a non-chlorine based refrigerant.


Now the part that you have been waiting for. I should make a title "HOW TO MAKE YOUR OLD R-12 SYSTEM COOL THE WAY IT DID BEFORE". This is simple.....get rid of the r-134a in the system. Now just because r-134a has a ozone depleting potential of 0 does not mean you can just vent (blow the charge) the system. The EPA still requires it to be recovered by a licensed technician with a 609 certification. So remove the r-134a and install a better r-12 substitute. Like FR-12. This is a refrigerant that is almost the same density as r-12. I use this all the time and it always works perfectly. It won't eat the hoses or o-ring either. You will actually have a little lower head pressure than the r-12 did. Also you do not have to change the oil!!!!! That means the compressor and engine do not have to work as hard. Here is a great link " target="_blank" target="_blank of course you won't need 12 cans but maybe you can find it else where. Remember that you are supposed to be licensed to do this.....but I 'm sure you are

Oh and lastly....don't bother talking or asking a automotive repair shop about this conversion.....they won't have a clue. They have been brain washed about " R-134a is the only way". But I can guarantee the technician has converted a system before and had the customer complain about the poor performance after the conversion. Sorry if I have offended anyone with my above opinion.

If you change to the refrigerant I suggested it will work perfectly for you. Good Luck!

oh... one more link " target="_blank" target="_blank