Expansion Valve Adjustment on Dodge Van After Switching to R-134a

Because...?

Don't see a parallel-flow condenser on this list. Means you will never get really good system performance. It'll never come up to the level of a properly-functioning R12 system in the same vehicle, especially in high demand situations (slow speed, hot days). On the other hand, if you don't make high demands of your A/C system, perhaps your threshhold of "acceptable" cooling is less stringent than mine.

At what engine RPM? 165 on the high side is low.

No such adjustment is possible.

the TEV or TXV more than likely needs adjustment when changing refrigerants. You may also need to change the thermostatic charge element. ( the bulb and diaphragm assembly ) You could check superheat and subcooling figures to figure out if the system is charged and the TXV is working correctly. I have no idea what those figures would be for an automotive system or if a replacement element is even available. To learn more about TXVs go to

mark

I have heard that sometimes the

This can *sometimes* be done on stationary installations -- TXV adjustment and thermostatic charge element replacements are not possible on MVAC, at least not on this system.

And I would add "not necessary." The required operating ranges for both R-12 and R-134a are well within the operating range of the TXV, so it just does its thing and doesn't care which refrigerant is flowing through it.