Ok now that I finally have the truck running properly I'd like to have a/c. I had never had the a/c belt on so I went and bought one. When I turn on the a/c button it lights up but the a/c does not work. The clutch does not engage at all. But when I put 12 volts to the compressor clutch it engages. Is it not engaging because the pressure is too low in the system or do I have some kind of electricle problem?

 

Sorry... 86 22re

 

Maybe, I've heard they have a low charge sensor that shuts off the compressor to protect it. Check the charge, if low you may want to convert to R134.

 

How can I check the charge?

 

Ok I'm pretty sure that my system is completly empty. I pushed in the little bike looking valve thing and nothing came...I did it on both...Now what should I do?

 

Get some de-natured alcohol and flush the system. Or find a friend that can get you R-12. You want to make sure there is no R-12 in the system. If R-12 and R-134 are mixed they will make some sort of acid, which will eat a hole through your evaporator and mess up the inside of your compressor.

 

Yeah that would be no charge alright I would take it to an AC shop and have them pull a vacumum on it for at least a few hours and recharge it with R134.

 

I've been told if you recharge it using ester oil that it is compatable with both the residue of the R-12 oil remaining after pulling a vacumum and new R-134 charge.

 

If you don't mind spending an extra $40 you can replace the old receiver/drier with a new one. I've heard that is where most of the R-12 oil remains after pulling a vacumum.

 

So you are saying if I use the oil I can charge with the r134 without getting every last bit of r-12 out?

 

As I understand it, pulling a vacumum for a number of hours will get the R-12 GAS out. What remains behind is the oil that was used with the R-12, but ester oil is compatable with both the old R-12 oil and with R-134. This info was from a Toyota tech I know locally and trust quite a bit. I chose to go ahead and replace the receiver/drier on mine just because I found they were only $40 online and I've heard that is where most of the old oil remains.

 

The oil that was given to me from a Toyota tech was Castrol Retro A/C. It is a polyol ester lubricant designed for use in R-12 or R-134a systems.

 

One more question. My magnetic clutch will not ingage unless I put 12 volts to it. I tested the wire that goes to it and I'm only getting .40 volts? Any ideas?

 

what i'd do is put 50 lb of nitrogen and a trace amount of r12 into the high side of the system. then you want to hav a leak detector to find if there is a leak. when you find it fix it and then charge it to lb specs. its best to weigh it in to get the proper charge. dont mess with the oil.

 

ps the comp wont run cause of the low pres. saftey cut out.

 

Charge it with R-12?

 

r12 is very xpensive and hard to come by in ca. for cars. if you put 134 in it it'll blow the seal and internal problems as well. a trace of 12 is to find the leak and nitrogen to give the pres. to make that happen. pulling a vacuum is only after freon is out of the system. you should pull it to 4 microns and then weigh the freon in. you can only use 134 after you retofit the system

 

Earlier you said after fixing the leak (assuming he has one of course) "and then charge it to lb specs". So did you mean for him to recharge it with R134 but don't mess with the oil?

 

well he most likley has a leak if there is no pres. in low or high side. but yiu cnt put 134 in a 12 system with out doing mods (retrofit). The 2 oils with these refrigerants are engineered to be compatable w/the refrigerant in the system so they can get back to the compressor to lubrcate. sorry if i was mis understood :pat:

 

So what do you consider a retrofit? Do you not agree that the Castrol Retro A/C ester oil is compatable with both R-12 and R-134?

I know they used to say you couldn't convert to R-134 with replacing all this stuff, but after Toyota did some field testing my understanding is that the systems will handle it just fine with the ester oil in there. This info is from a top Toyota tech at a dealership.