What year did the AC switch to R134a?

[f-two-fiddy]

I'm looking to swap the 93 to 134a and was have heard that the OBS 134 condensers had more tubes and fins. Is that true? I'd imagine I'll need a new accumulator/drier compatible with 134?

 

[BDCarrillo]

I can't speak to the condenser sizing, but the R-134A switch happened between 93/94. Note that some early 94's may still be R12.

You definitely will need a new accumulator for R134A, port adapters, new expansion valve, and all of your old O-Rings should be replaced

 

[f-two-fiddy]

Thanks, for the hit. I plan on doing a complete flush, and was looking for a new 134 condenser. IF they actually have a different design for 134.

Aren't the accumulator and expansion valve contained in one unit on the OBS systems?

 

[The Warden]

Thanks, for the hit. I plan on doing a complete flush, and was looking for a new 134 condenser. IF they actually have a different design for 134.

Aren't the accumulator and expansion valve contained in one unit on the OBS systems?

Unfortunately, I didn't get any pictures, but comparing a condenser for a 1994 F-350 (factory R-134a) with a condenser from a 1991 F-350 (factory R-12), they're definitely different. The R-134a condenser is far more efficient...it's a plate style as opposed to the tube-style you see on the R-12 system.

DEFINITELY worth the upgrade IMHO, although it means replacing the evaporator (which I believe is also a different design) and hoses...IIRC the factory R-134a stuff uses metric fittings.

Beyond that, I'd agree with @BDCarrillo...basically, to do it "right", you'd be replacing everything, but after dealing with R-12 systems converted to run R-134a, if you can afford it, I'd go ahead and replace everything. You'll have a better, more efficient system, and you shouldn't have to touch it for a very long time Yes, it's possible to run R-134a in an R-12 system with relatively minimal modifications (fitting adapters, conversion oil, etc), but it won't be as efficient and won't cool the cab as well as it will using factory R-134a parts.

 

[MTKirk]

If you are going to stick with the R-12 condenser and hoses, I would use a hydrocarbon refrigerant (enviro-safe, red-tek) instead of R-134a. It will run just as well as the original r-12, and at lower pressures. Less draw on the engine and fewer leaks. I prefer the old r-12 condensers, they are stronger and much easier to flush.

 

[Shawn MacAnanny]

I have a note r12 1993 and vacuumed system, new compressor, orifice dryer etc flushed lines and converter to r134 is works fine. The parts 94 I had did have 134 and the condenser is bigger. I can try to get a pic tomorrow comparing them. I plan on swapping it over when swap my engine.

 

[f-two-fiddy]

I think it would be worth the cost, and effort to replace the R12 stuff with 134.

I did do a conversion on my gasser. No flush. Just a junkyard condenser and some pag. I Drew it down for an hour and added 3.5 cans of 134. The thing puts out 34 degree air at 85 degree outside temps. With over 350K miles and a LOT of rust. I really didn't care what happened to it. But, I was sure surprised at the way it cools!

My diesel is putting out 45 degree air at 85 degree outside temps.

 

[MTKirk]

I think it would be worth the cost, and effort to replace the R12 stuff with 134.

I did do a conversion on my gasser. No flush. Just a junkyard condenser and some pag. I Drew it down for an hour and added 3.5 cans of 134. The thing puts out 34 degree air at 85 degree outside temps. With over 350K miles and a LOT of rust. I really didn't care what happened to it. But, I was sure surprised at the way it cools!

I bet it works great for the two days a year you need AC in Duluth. I was in Duluth in August 2009, froze my butt off!

 

[FORDF250HDXLT]

My diesel is putting out 45 degree air at 85 degree outside temps.

it might be just me but,i'll take 85 over 45 all year long if it were possible lol.

'93 chip truck.....ripped out the a/c system.
'93 log truck............a/c works but i never use it.
'98 honda civic......a/c works but i never use it.
'68 t-bird.....a/c was ripped out and in the trunk when i bought it.....parts now in garage and will never go back in........they will go on ebay though.

 

[typ4]

Too much over tech thinking on these conversions.
I dont want specifics / criticism from ac guys, most of us are on a budget and I have done professional ac work. I love it on pickups like ours, easy, everything new sucks.
All new condensors, regardless of type are made to be more efficient with 134A. Info, Mac's radiator, portland oregon.
All the hose fittings are standard thread up thru 93 as far as I have experienced, probably more since they are all oring fittings of some type.
94 to 97 are a different size fitting on the evap to condensor end, get one for your 93.
I have 2 systems of my own and 4 others at work/ friends running on r12 hoses that wont work. Make your own decision on this one.
Drain all the oil possible out of the components and flush before putting in the pag 46 oil or use the dual compatible oil, in this case my buddy recommends the 100 grade over the 46.
The evap is the same 134A or 12. Fitting change in 94 up.
The pressure switch can be adjusted on most, I turn it up 20 lbs on low side for cutout.
Always replace the dryer and orifice tube, cheap insurance.

Oh, DONT EVER USE SEALER!!!!
That is all.

 

[chris142]

Not all new condensers are designed with r134a. We have been returning new but unusable condensers due to low quality. Less tube and fin count than the stock r12 stuff even! Last one I saw was ordered for a 1996 and it only had 4 fins per inch...junk!

We pretty much stopped using 1800radiator over this

 

[The Warden]

Not all new condensers are designed with r134a. We have been returning new but unusable condensers due to low quality. Less tube and fin count than the stock r12 stuff even! Last one I saw was ordered for a 1996 and it only had 4 fins per inch...junk!

We pretty much stopped using 1800radiator over this

That's no good at all...have you found a source that has reasonably reliable quality, or is it all hit-and-miss these days?

 

[f-two-fiddy]

Yeah, it's not bad if you stay near the big pond. But a lot of my work takes me out of the chill zone. After working 10 hrs in high heat/humidity, it's nice to have a nice cool truck to drive home in.

 

[f-two-fiddy]

Not all new condensers are designed with r134a. We have been returning new but unusable condensers due to low quality. Less tube and fin count than the stock r12 stuff even! Last one I saw was ordered for a 1996 and it only had 4 fins per inch...junk!

We pretty much stopped using 1800radiator over this

What do you think of the 4 Seasons stuff?

 

[f-two-fiddy]

Well, after adding up the cost/time for a good R134 conversion. I spent $20 and got EPA 609 certified, scored 2 14 oz cans of R12 off'n ebay for $65, and a new heater bypass valve for $16. My heater box insulation is all beat up, so I'll redo something with that. And hopefully I can get down in the 30's outlet temps.

The last charge lasted 8 years, and still cools to a fair degree. If this one lasts 5, I'll be happy. The PO of my truck must have spent some money on the system right before I bought the truck. It has Goodyear branded hoses, and the Compressor was replaced. So hopefully a top off will get me thru a few more years. I'll be doing some searching for all the right parts. And will eventually convert.


How hard is it to get to the evaporator? I'd imagine it needs a good cleaning after 23 years.