47-59 Old Air System

[Zippi]

I have an Old Air Hurricane system in my 49 pickup. The Air does seem as cold as it should be. Can I use R-134a Refrigerant in this system?

[fauXGT]

Looks like the company was started in '89.
Do you have a model# serial#?
That might get you closer to manufacture date. I think it was the mid '90s that 134 started coming out. Have heard that old and new don't play well together, but I could be wrong. And a few have said that changing the evap and condenser will let you take 134. Check the fill ports to see if they are newer 134 or not would be my guess.

[mr48chev]

A quick eyeball check will tell you if your system was designed for R 12 or R 134A

Note that they used to have screw on adapters to use R 134A on converted rigs. If the push on connectors are built in it is for sure R134.

[1project2many]

I have retrofit many older systems to R134. It's usually possible without trouble but there are some changes that can make the new refrigerant work better.

First, old hoses are more likely to leak. The mineral oil used with R12 coats the inside of the hoses will act like a seal for R134 but it won't be a perfect seal. New design barrier hoses are much better.

That old system probably works with a thermostatic valve which should be fine with 134. If for some reason you have a fixed orifice cycling system, it helps to install a smaller orifice and lower the cutout pressure slightly.

Use an oil-based flush so you don't wash all of the mineral oil out of the system. Just like in the hoses, mineral oil will help o-rings and fittings seal properly.

I like using a synthetic oil compatible with r134 rather than PAG oil. PAG oil is glycol based and like brake fluid will absorb water.

Make absolutely certain you vacuum that system. In fact, don't be afraid to leave a vacuum running for an hour or more. Moisture left in an r134 system will react with fluorine gas in the refrigerant to create hydrofluoric acid. Hydrofluoric acid is strong enough to etch glass and does lots of damage to aluminum parts in an AC system.

If your system uses an electric fan you may need to adjust the turn on and off pressures and or temperatures. If the fan just turns on when the system is on you may be good.

Ultimately, there's a lot of videos and folks that will tell you you can install retrofit fittings then pressurize it with R134 and you will be good. In my experience those type of conversions don't last long and often come into the shop with more troubles than they had before the retrofit.

[Zippi]

Thanks for the info guys. My charge port measures about 14mm on the barb. This is the charge port by the firewall. The build on my 49 was started back in 2015 so the system could be as old as 9 years.

[mr48chev]

That system was designed for R134A No question there.

[1project2many]

Agree with mr48. No worries about adding R134. If the system is cool but not cold enough, topping off the charge might be just what's needed. Take a few extra minutes to hose down the condenser first and make sure it's not full of dirt and garbage.

[Zippi]

Thanks everybody. I called Old Air Products and confirmed that the system does take R-134a.

[mr48chev]

Wise thing to check with them. I'd follow 1project2many's suggestion and take the hose and flush out the condenser and the radiator at the same time to wash any dirt, bugs or what not that might have gotten in the fins.

We can't go down and buy R134A in this state since the state banned the sale of it but I can have my son bootleg me some from where he lives. I'd suggest putting the gauges on it or having someone do it to be sure of exactly what you have going on before you just add a can though. That might include watching the sight glass for bubbles.