So the system on the wife’s 91 doesn’t blow cold. Not a big deal being a convertible. But figured why not fix it for those days she might get caught in the rain.


I saw video where someone used this kit to upgrade and replace their system.

https://www.rockauto.com/en/moreinfo.php?pk=12701437&cc=1251560&pt=17507&jsn=865

Price seems decent. Was curious if anyone has any experience with it?

figured I’d add some leak detection dye to the current system see where the leak is. Hopefully it’s one of the parts being replaced or a oring on a hose.

 

If the system is still r12, it's likely the connections haven't been opened in 30+ years. The lines are almost all dissimilar metals, so they love to seize. Be prepared for the liquid line to evaporator to be seized when you go to replace the orifice tube. If you're able to get it apart without breaking the lines, id recommend a Ford red orifice tube rather than the white GM. Evaporators HATE debris, both inside and out. It's fairly easy to remove the top of the evaporator housing to inspect the core for 34 years worth of leaves/organic material that may be blocking airflow and rotting the fins. If you're willing to spend the money to replace the compressor, you may consider replacing the evaporator at the same time. Make sure all the seals are in place on either the new or existing unit. Flushing is a must. You don't want any trace of the old mineral oil in the system.
Most kits don't specifically tell you, but the valve covers must be removed on the r12 service fittings to install the retrofit fittings. Any joints you take apart, make sure you replace the orings with the correct green equivalent.

Finally, most systems prefer about 85% r134a charge to the stated r12 capacity. You can ultimately fine tune it using pressures and condenser inlet/outlet temperature but it's a good place to start. Dye is a great idea as well.

91 SHOULD have barrier hoses already, but it's not a guarantee.

 

I had success with r134 conversion. Airflow details matter. Running T-tops off anytime driven, but it does still help. https://www.thirdgen.org/forums/cool...ml#post6311001

 

Currently running 134a with upgraded LS1 fans. Blows nice and cold!

Im also experimenting on my S-10 with the "air duster" aka I believe R-152a?? That seems to have really nice results as well.

 

Really need a different condenser as well.
I believe 134a uses a crossflow condenser.

 

I think I’m going to use one of these R12 compatible charge with dye to see where the leak is first and see where it goes from there.

 

sounds like a good plan if it is safe. what is compatible?

 

Seen this at my local auto parts store. Says it replaces r12.

 

I've used those, they work pretty good. If I recall lyou''ll need a hose that goes to a R-12 connector though since you still got the R-12. Almost impossible to find around here but hopefulyl easy for you.

My guess is the seal on the compressor is what's leaking.

 

I just did mine on a 87 IrocZ, I replaced the compressor with a R134a R4 heavy. Repaced the accumulator all O rings and flushed the entire system. also replaced the compressor orrifice with a R134a orrifice. all went great until pulling a vacuum/ The low side port on the back of the compressor is leaking It pulls down to zero not 35. The O rings are a little congusing they are the high pressure metal and rubber ones. One is thicker then the other and its red. the other is black. I believe the thicker one is for the high side port but it sure doesnt look correct? Im ready to try some good rubber O rings but because its a retrofit from R 12 to R 134 A Im not sure? Anyone had this problem? Or has anyone dealt with these kind of O rings? Or some call them gaskets? They did come with the new compressor.At least they are easy to switch out and easy to get to. It all went so smooth so its pretty frustrating to have this issue. any help would be great ly appreciated.

 

Any advice on the kind of oil added in for the conversion over to 134a?

 

I used PAG 150

 

Yeah I got bad o rings that came with the reman R4 heavy compressor for R134a. I can actually hear the air hissing from the low side port on the back of the compressor. Gonna go with the green donut style. Hell with these metal rubber rings. Complete junk.

 

Since you are doing a conversion, you want to make sure it is compatible with prior oil to be on safe side. I think this is what I used, and will post link that describes details. Also has link to oil research. (post #81) https://www.thirdgen.org/forums/cool...ml#post6427676

 

being I replaced the compressor and accumulator with new ones and did a complete system flush a retrofit is recomended using pag 150. The compressor
is also made for pag 150. It not too tough of a job.

 

Yeah good info. Mines a GM R4. I used the same orrifice tube as you.