Anybody know how much refrigerant I should expect to put in for a full charge? I ask because I put a fresh charge in after a repair to the high pressure hose on my daughter's recently acquired '91 Explorer and it only took 2 - 12 ounce cans of R134.

This Explorer was supposed to have been converted over from R12 by a shop, and it does look like it has a newer compressor, although the accumulator has the old-style fittings. The pressure reading is right at 50-55 psi, so it seems right, but I would have expected put in more than just 2 cans. Furthermore, it's not as cool as I would expect.

I know, it won't be as efficient as the old R12 system, but I think it can do better. Would I be inviting trouble if I tried putting a 3rd can in even though it reads a full charge?

 

If a (legitimate) shop converted the system to R134, both the high and low side ports should have the new fittings on them.

Putting in more refrigerant will only serve to make it even warmer. 50-55 psi seems as though the system is already overcharged, unless you aren't getting any airflow across the condensor. Was the system already evacuated when you added the refrigerant, or was it just too low to let the compressor run?

 

rule of thumb 70 to 80% of the original r-12 charge. but to really du it right you need a set of gages that will give you both high and low side. then 2.2 x the ambant temp at the condenser for the high side