mldave

Someone installed an A/C unit in my 86 truck using R 12 parts and changed the fittings over to take R 134A.This never throws out real cold air and was wondering if putting a R 134A condensor in would make it colder?Also the A/C amp board is bypassed by a jumper wire,as the amp board in the unit is non -op.What affect would this have if any on the unit running colder?

nothingbetter

A condensor is a condensor, just a tube winding back a forth designed to remove heat and turn the high pressure gas to a high pressure liquid. Thats not your problem.

The pressures required in an r134 system need to be higher than in an r12 system for it to work the same. When the r134 was put in, if all the r12 was not recovered it can kill the a/c system by damaging seals, bearings, valves and pistons.

You may need a different pressure switch as it will cause your compressor to supply higher evaporator pressure seeing as that is required by r134. The compressor switch is usually found on the accumulator or the receiver/dryer depending on what kind of system you have, but is always somewhere on the low pressure side of the system.

Also your metering device (either a thx or an orifice tube) might be incorrect, as it also controls the compressor and the flow of refrigerant.

As you can tell, its not nearly as simple as changing the fitting and calling it a day. From what we know, the whole system could be pooched if all the r12 wasn't recovered. Or if all those things above were changed at the same time as the refrigerant was, maybe you just have low refrigerant level, or moisture in the system. Or maybe your accumulator/receiver is full of moisture as it was taken from a junkyard and sat open to air for a week in the garage. So many possibilities on something like this.

What does your sight glass look like?

abecedarian

Cold air comes not from the condenser but rather from the evaporator behind the dash and how the expansion valve / orifice tube there works.

Mandy Tuning

most times you cant use to much refrigerant of r134 as with r12 cause the high pressure.a more efficient condenser will lower your high side pressure reducing heat and accepting a bit more charge of r134.same goes installing an aux electric fan or replace the fan clutch with the villager/quest fan to mention a popular swap.you will notice the a/c cools better when truck is moving than when is in a stop.also when you spray water with a hose at the condenser it cools more and high side pressure goes down, all this is cause a more efficient condenser,so yes, a more efficient r134 condenser will make your a/c cool better compared to r12 condenser.

mldave

Thanks for the replies.Yesterday morning with the outside air at 86 degrees and some humidity the vents were blowing out temps in the low 60's.This after driving on the highway for twenty minutes.By the afternoon with outside temp at 100 degree's it was cooler with the windows down and wing vents open.If I had the cash I'd have a new unit put in..but that's just a dream at this point in time.