Converting AC to R134A

[Q45-V8]

So my air conditioner isn't working that well over the past year and clearly needs more refrigerant, but it's never been upgraded, so my garage can probably do it.

Is this the kit I'll need off the bay ?

https://www.ebay.com/itm/221527838106

[elwesso]

The short answer is, no that's not what you want. There's multiple things going on here.. First of all, you don't "have" to convert the fittings on the car, however most auto shops probably wouldn't have the old style gauges. Actually, R12 cars used the same gauge connectors as most HVAC units (like AC units, commercial refrigerators, etc). I worked on an old Q a long time ago and I just used my R22 gauge set and you can vacuum/charge just fine, even though I charged with R134a.

If you want to convert to R134a fittings, you'll need these.. Those will convert your existing R12 ports to work with automotive R134a gauge sets.

http://www.ebay.com/itm/R-12-to-R-134A- ... NA&vxp=mtr

I believe when you install those you have to take the schrader core out of the existing port, which means you'll need to evacuate the system first. Basically the same idea as taking a valve stem out of a tire.

The *MOST CRITICAL* part about converting is making sure you get ALL the old oil out and replacing the filter drier (sometimes called the accumulator). That means forcing some sort of solvent through the condenser, evaporator, all the refrigerant lines, and of course changing the oil in the compressor.

On another note, if the system is working but just working poorly like it needs recharged, you could try this stuff:

https://www.amazon.com/Freeze-12-Refrig ... =freeze+12

I used it on an old BMW I had that had a completely flat system. It didn't work "as new", mainly at idle/low speeds the AC would struggle to keep up, but when cruising at normal speeds it worked great. Bottom line for the money, it was better than no AC. Note also that by converting from R12 to R134a your AC will never work as good as factory.

If your system still has refrigerant in it and doesn't need evacuated, I'd give the freeze 12 a try.

[Q45-V8]

Thanks, Wes...

The AC works fine at normal speed, even traveling at like 20 mph. It struggles at idle and the air is barely cool.

I guess I could buy a pair of cans of this freeze 12, maybe that'll help a bit at idle too...

How do I inject it directly into the system?

[3Q Jay]

best to first read the pressures and post up the results. the differential between high low as well as the absolute, including idle vs. 1200 revs can tell a lot.

[Q45-V8]

How does one read the pressures? Understand, I have literally never done any AC work in my entire life.

[3Q Jay]

'manifold set'
amazon will have a ton to choose from. careful, you may vent some refrigerant if you are not familiar with making the connections.

[elwesso]

This looks a nice set. Includes the adapters for quick-connect R134a too, pretty nice.

http://www.ebay.com/itm/R134a-R12-R22-A ... 1290302374

To read the pressures all you do is hook the high side up to the high side service port (located up by the passenger side headlight on a small metal line) and the low side to the low side service port (located on that metal can thing on the firewall on the passenger side)..

I agree with Jay, before you do anything its best to post the pressures. Knowing that your AC works fine at normal speed but not at idle could mean different causes depending on what the pressure readings say. Could be low on refrigerant, or could be the compressor is simply worn out (and if you're on the original refrigerant means probably the compressor hasn't been changed, and it's probably on borrowed time as it is).