Is the 1991 ls400 usually r134 or r12?

 

R12.

I think they switched to R134 in '93 or '94.

 

i have a 91ls400. I recently fixed my leaking a/c. I did not know that the 91's use r12. my a/c system was drained since this winter. So i put r134 in the system about 3-4 weeks ago. I have no probs so far. It's not making any noises and it works pretty good. Does anyone know if its ok to do this? Can i leave the r134 in the system? I did some fitting mods. please let me know. thanks