Freeze 12 vs. 134a?

[spdrcr29]

Originally Posted by truckdude239

much to common believe about having to flush the system when converting you do not have to any ore just pull old out with a system put in new oil and r134a with the new fittings as simple as that

I was told the same thing as above by 3 different a/c shops.... No Flush, vac out the old stuff, replace with Ester Oil (not PAG), add R134, add new fittings, and drive down the road after throwing the mechanic 150 bucks.
2 shops also said the A/C should be 20-40 degrees colder at the vents than ambient temperature, which is the bar for measurement in their opinion, but they told me not to even try getting a good read till it was 70 degrees outside. I live in Michigan, and right now its looking like it'll be July before we get any weather in the 70's, so I'm on hold with this conundrum.

R134A molecules are smaller (faster leakdown), but the good news is, R134a is available at parts stores for about 20 bucks for the hose and a can, so if it is a small leak, you can recharge it in the spring without the hassles of R12.