Hi all, first time posting here. I've done a search but couldn't find what I needed. I'm wondering if i need a new compressor or rebuild on my '93 Loyale. Did the R134 conversion but when i'm charging the A/C system and the pressure gets to about 20 psi, the compressor kicks on and the pressure drops to about 5 psi and there's no cold air. If i try to add more freon the compressor kicks off around 15 psi and then the pressure instantly jumps to and holds at about 40 psi.

 

Is my compressor shot? The dealer says they haven't sold a rebuild kit in years and Autozone/Pep Boys doesn't carry them.

are you looking at high side or low side pressures? did you have it evacuated properly? it sounds like your compressor is ok but you may have skiped some steps in the change over. at least to do it properly. not the walmart kit way.

If thats low side, thats not uncommon, you could have a resriction somewhere though thats keeping it from coming back to the low side, if its the high side, thats way too low, but be warned the R134a will leak out of the R-12 hoses, it'll take a while but it will none the less.

 

to get more in try to jump the low pressure switch, that'll keep the compressor spinning, and then it will take in more refrigerant. and have the bottle warm, like with one of those heater pads you put in your socks or gloves, not much hotter, don't, don't use a torch, thats bad, real bad.

System has been empty for quite a while and i'm using the Wal-Mart kit which conists of a hose with a gauge and R134. What do you mean do it properly? Should i not use a hose and guage setup? I know i should've replaced the receiver/dryer but was hoping i may not need to since the system's never been opened. I'm reading the pressure on the low side. Any other ideas w/o taking it somewhere and spending big bucks?

Do you know where the low press switch is and how to jump it? The Haynes manual only talked about jumping the A/C relay behind the right strut tower. Btw, i tested the relay and it clicked.

to do it properly you would have changed the reciver dryer. you have residual oil and moisture in the system that shuold have been evacuated by pulling and holding a vacume on the system. that is most likely why it will not charge.

 

did you fix the leak?

you also should have drained the oil from the compressor and added new pag oil.

 

there are more things to check but its too late for all that.

 

you should be using high and low side gauges as well with the ability to understand the readings.

 

I dont like the POS wall mart kits because they mislead people into thinking that the change over will be a simple job easy to do at home with no special equipment. IF all goes well you may be able to buy a year or maby two at the most of decent A/C operation.

 

sorry to rant but as an auto tech I find it troubling to see these things on the market. there is no place for them in a responsible auto repair market. its like slick 50 or tune up in a can. all junk designed to get your money and not fix your car properly.

Thanks for the help. Guess i'll have to do an evac, change the Rec/Drier, remove and clean the evaporator, dump the compressor oil and pull a vacuum to see if i have to replace the compressor. Will enough of the old oil come out to use PAG?

if you drain the compressor and then have a the lines evacuated after you will be all good. and dont be too concerned about the old hoses leaking. the old oil that has soaked in to them tend to help seal em up. but do try to find yor leak. look for oil and dirt by fittings or at the compressor.

Ok, i'll do that. Should i install the compressor and new rec/drier before having the lines evacuated?

 

 

I don't think i have a leak. Couldn't see any dye coming out from anywhere.

Just a couple things.

 

 

If the front seal on your compressor isn't leaking, then it's usually an O-ring. There are O-rings at every hose and line connection. Typically, they fail first.

 

Also, whenever you convert to R134A from R12, you need to change the receiver/drier. They used 2 different kinds of dessicant in the driers. The older kind is NOT compatable with R134A...so, for about $25, it's best to get a new, R134A compatable receiver/drier.

 

RedLance

change parts then pull a vacume. it helps with the charging too. good points from red lance and noahdl88

pressure in a 134a system lo is 13, and hi is 180

 pressure in a 134a system lo is 13, and hi is 180

 

I am not sure what you are getting at here. thats more than a bit vague.

 

there are lots of pressures that vary greatly depending on conditions. it also depends on what side you are looking at. engine running or not.