NOS Motorcraft AC pump, can I run R134A?

[6 Nebraska IDIs]

Im probably going to buy 70post455's AC pump and parts he has for sale to use on my brown truck.
http://www.oilburners.net/forums/showthread.php?t=25316
But I am wondering if the pump can be used with R134A or not?
I've heard that you cant run R134A unless the pump was built for it.
I dont want to seize up or leak out anything, so do you think I can run R134A through that pump?

 

[160k87F250]

I dont see why you can't. They make kits to convert R12 to R134, and all thats in the kits are different fittings and different oil. I think I would definitely replace the drier also, just to be on the safe side.
John

 

[6 Nebraska IDIs]

Yea, Im going to replace all the lines, the drier, and probably have the cooler cleaned out. I'd heard something about the R134 not agreeing with R12 type seals. But maybe thats just some mechanic trying to make money, I dont know for sure.

 

[160k87F250]

If you have it all apart, replace all the o rings anyway. Then you'll be good. I've got lots of extras if you need them, but I need to know what size.
John

 

[reklund]

No issues running 134 in a R12 compressor. As mentioned, I'd clean out the evaporator and condensor thoroughly with a AC system flush kit to remove all the old oil, replace all the orings while it's apart, and replace the reciever/dryer and orifice tube.

The *MOST* important part of any AC work is to draw a good vacuum on the system for at least 30 minutes (preferably longer) to get all the moisture out of the system. Also, don't leave the new receiver/dryer uncapped or hooked into an open system too long, as it'll absorb moisture out of the air and defeat its purpose. Hook it up last, and then put a vacuum pump on it ASAP.

If you do it right, you'll be able to hang beef in the cab of your truck it'll be so cold!

Ryan

 

[RLDSL]

With a new compressor, you won't have any trouble with the seal on it. Make sure to take the cover off the ports on it and drain the oil out of it while turning the thing.

Yes, replace all the orings, and get a bottle of Nylog to lubricate/seal the things. Don't use Pag or Ester oil on them, they WILL dry up and leak.

Make sure to add the appropriate amount of oil to the system.
A variable orifice valve is a great investment to get colder duct temps

 

[RLDSL]

Also, if your old compressor siezed up or got crunchy, make sure to flush he system thoroughly before installing the new one or you'll be doing it again next year

 

[EMD_DRIVER]

Yup... I converted both my R12 systems to 134.. Cold as ice!

Gary

 

[6 Nebraska IDIs]

Where are all the orings that I am going to have to replace?
Where can I get that Nylog stuff at and how do I use it?
How is this variable orifice valve used?

 

[BigRigTech]

Geesh, all I do is recharge my R12 system with 134A every spring and it's ice cold all summer. I didn't change anything but to install the R134A fittings....My system leaks out in the winter (atleast it did last year) but I found an o-ring out of place this spring so it might hold fine this winter....Nice and cold all summer...Maybe not ideal for you southerner's but for my 30C hot day's it works great......I don't reduce my charge level either like they tell you to. I put in 2lbs-12oz.

 

[6 Nebraska IDIs]

What do you mean reduce your charge, and what do those numbers mean?
If its that complicated I'll probably just put everything together, and take it to one of those AC shops to have it serviced.
But if any of you would like to explain the process, by all means I could probably do it my self and save me some money to do my other mods to the truck.

 

[BigRigTech]

They say to reduce the required charge by 20% when you switch from R12 to 134A but I don't...The 134 doesn't work as well as R12 so in my mind a little extra refrigerant to absorb the heat isn't a bad thing....No problems with my system since I've had the truck. I have a spare used pump just in case as I refuse to drive anything daily that doesn't have AC anymore.......I must be getting old...haha

 

[sle2115]

You are supposed to use 80% R134 to the specified R12 charge. If your sticker says to use 10 ounces of R12, you would use 8 ounces of R134. The thing to remember is those stickers are only a starting point, they are not the gospel for ice cold air. You need a gauge and testing to figure that out. Overcharging any system is as bad as undercharging, it will often freeze the evaporator, thus not allowing air to flow through and it will seem like it is not making cold air, when in fact, it is making too cold air. I charge it by the gauge and modify it by my custom gauge, my face!

Here is what our 4 seasons rep told me they found:
Any hose or seal that has been saturated with R12 oil will not leak R134. They did MAJOR testing on this. So, if you replace a seal, make sure it is R134 compatible, same with hoses, but about all of them these days are. R134 will leak out of a new R12 hose or oring, been there, done that. So, just change the system out, flush it if you lost a compressor (better to do it anyway and you can get a flush kit for about $30-$40 from JCWhitney or other places), then replace any orings you care too. I would also throw an R134 orifice tube in it and a new accumulator. Vac it out for at least 30 minutes, longer is better and this is also a good test of the system. Pull a vacuum, let it sit overnight. If it still has the same level of vacuum, you are good to go. Also, as was said, drain the oil out of the new compressor and replace with the proper type.

 

[6 Nebraska IDIs]

My old pump is seized, and hasnt ran in god knows how long.
The truck sat for over 15 years in a garage without running, and Im sure thats what did the pump in.

 

[RLDSL]

Where are all the orings that I am going to have to replace?
Where can I get that Nylog stuff at and how do I use it?
How is this variable orifice valve used?

You will have an oring at each joint in the hoses and one at the quick coupler before the orifice tube ( which you will likely need a spring lock tool to open up depending on year, a couple of bucks at the parts store ) True, orings saturated with r12 mineral oil in service will usually hold, but on aged systems or ones that have been sitting without mineral oil regularly circulating on them, you can pretty well count on them being bad. You will need to replace them.

You can get Nylog here get the blue for use with PAG and Ester systems Coat the new orings with it to lubricate the ring for instalation and seal the joint.

A variable orifice valve is used in place of the factory fixed orifice tube ( which you need to replace anyway ) it adjusts the size of the hole and makes for much cooler duct temps, you can get them at advance etc, I can get a part number if needed. they run about $30-35 , but they're worth it. I stick them in every system I open.

If the old comp seized up, you definitely need to flush the system . Seperate all of the fittings, remove the condenser and lay it flat, get a quart of ac flush and you can pour it through, but a cheap siphon gun from Harbour freight works great to spray the stuff through , then let it sit a bit and blow out with rubber tipped blow gun. Flush all componants till they run clean An air drier on the shop air is strongly recomended to cut down on the time needed running the vacuum pump, as it is, really should let it run overnight after flushing and re assembling unles you have a real stout vacuum pump

You should be able to adjust the screw on the back of the pressure switch to cut out at a lower pressure , around 20 -22psi for the R134a this will make it colder