R-12 refridgerant to 134

[Itali83]

What I’ve found to be the number one overlooked thing is the low pressure cutout switch. It’s adjustable. No one knows that it seems. When switching to r134a, you need to adjust the switch to let the low side pull down to a lower pressure than it did with r-12. If not, especially at idle, the pump will cycle too much and not let the Freon evaporate completely and will give poor idle cooling and only marginal road speed cooling. I keep my trucks r-12 but my suburban was already converted to r134a. Everything worked but like you guys are experiencing, only barely. I adjusted my low side switch and I can hang meat in this truck even in the dead of summer. Yes I also have rear a/c which makes a huge difference. My 82 K10 with r-12 is stupid cold with the tiny single cab. It’s great.

Just my experience with my trucks


Ben

 

[80BrownK10]

If you are converting the AC, you need to change a few components also.
You know that, right?
I'm thinkin dryer, condenser, and orifice tube is required for 134A.
Likely the same amount to switch. It's not much..but I dunno how much juice. Aint but a couple pounds....2.2?

Not really interested in AC - Ive always let another tech have those jobs...but I converted my IROC.

Hope this helps!

Nope you use about .8 of the r12 amount or for those who can't convert % to decimal and vice versa that's 80%>

 

[80BrownK10]

DON'T CONVERT TO R134a FOR THE LOVE OF GOD!

You can still find R12 if you look hard enough. Cool part about R12 is that it actually works. The few vehicles that I've owned that have been converted sucked (including my current Burb), most you'll get out of that thing is "cool" air for a while. On new stuff that is designed for R134a it is sufficient, but for old stuff that should have R12 it doesn't really do a great job IMO

I converted my 1990 ranger. I personally converted it and did the work myself. Other than like a switch that leaked it held for years. Basically a 10 year life span when I sold it and it was still working strong then. You could hang meat in that cab. The back window here in SC would fog up along with the front corners of the side windows. Again it did loose it charge once...I figured out it was the cut out switch. Just bought a new one with a new o ring (didn't want to chance that a new ring would stop leak), and it had held charge for like 6 years at the point I sold it. I did replace the condenser when I did it all because the new one was punctured from a minor front end collision. Everything in that stystem was actually replaced except the suction line that was hard.

 

[RecklessWOT]

I converted my 1990 ranger. I personally converted it and did the work myself. Other than like a switch that leaked it held for years. Basically a 10 year life span when I sold it and it was still working strong then. You could hang meat in that cab. The back window here in SC would fog up along with the front corners of the side windows. Again it did loose it charge once...I figured out it was the cut out switch. Just bought a new one with a new o ring (didn't want to chance that a new ring would stop leak), and it had held charge for like 6 years at the point I sold it. I did replace the condenser when I did it all because the new one was punctured from a minor front end collision. Everything in that stystem was actually replaced except the suction line that was hard.

I'm not worried about it not being able to hold a charge, I'm more concerned with the refrigerant's cooling abilities. R12 produces much more "cold" in the old systems that were designed for it rather than the "good enough" R134a replacement. It's fine on new systems that are designed for it, but on older stuff it doesn't cut it.

 

[SquareRoot]

I "flushed" the entire factory system right into the dumpster. Replaced it with Vintage Air. Lost miles of useless hoses, cables, vacuum pots, ****** swinging plastic doors. Blah blah blah.

I was left with cold, reliable air and a clean firewall.

 

[75gmck25]

Another common conversion item is to switch from the GM white orifice to a Ford blue orifice, since it should work better with R134a.

I used R134a and PAG 100 because it’s an industry standard. Alternative products might work, but most shops can’t recover them or charge with them. I prefer the easy route for future maintenance.

Bruce

 

[1987 GMC Jimmy]

I "flushed" the entire factory system right into the dumpster. Replaced it with Vintage Air. Lost miles of useless hoses, cables, vacuum pots, ****** swinging plastic doors. Blah blah blah.

I was left with cold, reliable air and a clean firewall.

Ha, I laughed at that

Another common conversion item is to switch from the GM white orifice to a Ford blue orifice, since it should work better with R134a.

I used R134a and PAG 100 because it’s an industry standard. Alternative products might work, but most shops can’t recover them or charge with them. I prefer the easy route for future maintenance.

Bruce

Agreed. I did also step up to the white o-tube after my second or third time. I think it’s slightly better all around. I’ve thought about stepping up another level to orange or red, can’t remember which one, but I didn’t want to risk highway performance, and I’d rather have middle of the road performance at all times rather than heavily compromising standstill or moving cooling ability.

 

[olnick]

Check out DexCool It only takes one pound to work BETTER THAN R12 I did the conversion 5 years ago and have not touched the system since then! Still blows super coold!

Olnick

 

[Snoots]

I used a Variable Orfice Tube and changed to a Low Pressure Cutout Switch when converting mine and it'll freeze you out on a hot day.

 

[Chevyguy]

Exactly. My 87 Burb was also professionally converted about a year before I bought it. I haven't used it in years, I don't think it even works anymore because I haven't bothered recarging it. The first summer I had it when it was nice and fresh If I was going 60mph it worked alright, kept the truck "cool". But at those speeds so does rolling the windows down. When I'm at a crawl in a traffic jam or just going light to light in a more populated area it did nothing whatsoever, and I would bake to death inside the damn thing.

ESPECIALLY in a Suburban that doesn't have rear A/C, with the sun beating down on those 147 linear feet of un-tinted windows like a big greenhouse made out of magnifying glasses the poor thing couldn't even stop the heat from rising in the cab let alone cool it down. Better to just roll all the windows down and stick your head out to gasp for air

You shouldn't have to recharge your A/C system unless you have a leak in the system. If it was rebuilt by a shop and everything was done properly it should be fine.

Sent from my SM-A705U using Tapatalk

 

[80BrownK10]

You shouldn't have to recharge your A/C system unless you have a leak in the system. If it was rebuilt by a shop and everything was done properly it should be fine.

Sent from my SM-A705U using Tapatalk

Probably done by a shop years ago and is wore out now.

 

[peats]

there is another part of this whole AC thing that most don't address and that's insulation. once the floor pan heats up from the driveline and exhaust, it's that much more load on the AC. lizzard skin underneath and dynamat inside go a long way to keep the heat out as well as quieting the cab. i also have heat reflectors on the mufflers of my k5.