maddogandnoriko

We have a 93 4Runner, manual, 4x4, e liter V6. 10 years ago we Converted from r12 to 134. Recently the ac went out. Took it to Pep Boys and they did something for $50. I assume they topped it off. It works again. Cool. I bought guages, a leak detector, dye to track any potential leak.

What should my pressures be on high and low side for a converted system? I assume the factory r12 readings don't apply. Thanks for your help.

millball

Not possible to say, as pressures depend on ambient temps. Google r134 temperature charts. Pick one.

scope103

Millball is correct; measuring pressures without temperatures is completely pointless (even though the parts-store a/c-in-a-can will tell you to do just that.)

Here's what I know about R134a conversions: https://www.yotatech.com/forums/f116...-r134a-284801/

Even though I measured recharge with pressures and temperatures, I've since learned that is considered to be second-best. The "right" way to do it is to recover all the current refrigerant, weigh it, and recharge to the specified total charge. (An R-R-R machine does all that automatically.)

As for the R134a temperature charts, it's actually built right into your gauges.

As you suspect, for $50 Pep Boys probably just "topped it off" (using one of those R-R-R machines). But refrigerant doesn't just disappear; you have a leak. Buying gauges was a wise choice. If you care, while deliberately venting refrigerant to the atmosphere is a crime, it's not illegal to top off a system with a known leak. Go figure.