Hello,
I have been noticing in the automotive departments of our local Wal-Mart’s and Meijers that they sale kits to convert an R-12 system to R-134a system. This kit is like 39.99 and it includes pag oil I think, the tool to put this stuff in your system, and a couple bottles of R-134a. I opened the box and looked at the instructions. They said that you could leave the system the same, just add these things. This is granted if the system is blowing hot, like mine. They say that you can leave the mineral oil in, just add the pag then the r-134. Is this a good solution, or should I pass this one up. Local shops want 60 dollars just to look at my system, and 70 a can for r-12. I have a 92 explorer.
Thanks for your time; you guys are very helpful,
Sean

 

For the most part this is true, but you have to be carefull adding the oil, if you have too much in the system, it wont work very well. The best way to do it is to remove your compressor and poor as much of the oil out of it as possible and add the same amount you dumped out back in with the pag. Do the same with the dryer/accumulator, better yet, replace the accunulator. Also your O'rings, if your car was built prior to 1988, your seals are not compatible with the pag oil, and will eventually start leaking. In short, coverting it is fine but to do it right you should change the drier, the o'rings and drain your compressor, re-add the right mount of pag oil, and charge your system with the 134a.
I hope this helps.

 

Thanks for the advice. I also wanted to ask if this is something the average person should do? I mean do I need to know alot about A/C to do this conversion? They make it sound so simple in the instructions but I am wondering if it really is. I don't want to ruin the whole system by doing this, is it possible to do that? I am just trying to save a buck and stay cool this summer. Thanks for your time.
Sean

 

The correct way to do this is to remove all old oil possible (flush evap. and cond. to remove oil). Drain compressor. Replace accumulator. Replace all o-rings. Add Ester or Pag oil directly to components. 6 ozs. total. I put 2 in the suction port and the rest in the accumulator. At east 45 mins on a vacuum pump. Recharge at 80% of R12 capacity. Use guages. Use approved flush solvents. Wrong stuff will do more harm than good. Use proper flush system. Rotate compressor by hand at least 12 rotations to remove installed oil from top of pistons after you hook all lines back up and before you run it by the engine.

 

I've been through the conversion gamut with much of the same components you mentioned. In hindsight, I can offer the following:
Ford states there is no need to change old oil out, just use the PAG. In older systems much of the original oil is gone already. Ideally you could change out the evaporator but again Ford mentions this is not really necessary unless the system has been opened to the air for "a considerable length of time".

The condensor and high/low pressure hoses will work fine with R134a. The compressor also will work with R134a. If you have any pressure at all remaining in the current system, then you should not have to evacuate, just add in the new refrigerant. The trick is how much to add. Underfilling and overfilling will both produce undesirable results. Have a station remove any remaining R12. Initially, add 4 cans of r134 and test your A/C system for results. When the proper amount is added, the high pressure line going into the condensor and the low pressure output line should both feel equally cold. R134 is not as efficient at idle/low speed as R12. The center vent temp should be able to register 38 degrees at highway driving, on low fan speed. You wil have higher temps at idle.

If you are tempted to go the whole nine yards and buy gauges, I would not recommend the Interdynamics brand that is sold alongside these conversion kits. The gauges are very poorly made and cause more trouble than they are worth. For about the same price, you can get better gauges at ackits.com. Also, there is a wealth of information for DIY guys at the same site.

Good luck!

 

Thank you Dvinlli and aerocolorado. I'm right at that place in my rebuild of my 77.

In blowing out my "little round thing" (Dryer?) (Evaporator?) I get little peices of grit, like fine sand.
I cant seem to get it all, so I'm guessing I'll have to buy a new one of them???? Unless you guys have a better Idea?

The system's been open for two years. I'll see what's in the Compressor and if it's pretty dry, I'll put the PAG in and install it.

How about an 'O' Ring kit? Who'd have that?

 

At work our Ford Mech's (We swiped them from ford) retro'ed several E350 and SuperDutys and the PROBLEMS! Flush everything out! If you can't flush it - replace it. The the system will work great! They had the same ptoblems with the few Chevys and Dodges!

 

O ring kits, containing a selection of sizes of both rings and garter springs, are available from ackits.com. After re-reading my own post, I noticed an error. The lines at the firewall going into and out of the evaporator (not the condensor as posted - brain fart) should be equally cold at steady state conditions.

 

The receiver/dryer has a dessicant that absorbs any moisture that gets into the system. Moisture and R12 fiddle around and form ACID. Bad. Grab the moisture with a dessicant. Ta Da. no more acid. But. The dessicant is in a 'cloth baggie' of some sort that can get broken open by gremlins(?) and float around along with R12 and oil. And stop up all those expensive parts.
R134a requires an X7 or X9? dessicant that would also work with R12 if you continue with R12. The 'baggie' or container is R134a-proof. You should consider using ESTER oil or Texaco HF100, as mentioned on ackits.com board. All there point fingers at PAG as hygroscopic to the point it can ruin a good system. Also required, as mentioned, are new O-rings that will withstand R134a.
You can try the kits, but mixing R12 and R134a in a system is a recipe for disaster. To work, it honestly must be vacuumed out. I get no $$ for saying that. You will more than likely have marginal performance with R134a at low speeds because the factory condenser is just not able to transfer enough heat and the fan/fan-clutch are probably old and ineffective at low speeds.
'ust my 2 cents.

tom

 

:-) That was one heckuva good explanation Tom.

It's been awhile since I worked on that truck. I put a new Condenser (little round thing) and managed to blow some flush through the Pump and put the oil that comes with the R-134 Kit in there.

I cant remember about the 'O' rings. Whether I bought a kit from a company that was suggested or not.
When I get time to get back to the Ford, I'll have to start all over.

I was missing one little part though.

It's called a "Quick DIsconnect" and it's in between the Sight Glass and the Condenser. Just a little flexible brass connector I guess. I didn't take it apart so I just dont know what I'm looking for.

Have'nt had time to go into the Wrecking yards, or check with Ford.

Does anybody know what it is or where to get one?

 

If you want the correct method of doing this go to www.epatest.com and look at the manual listed in section 609. This will proove most of you wrong.

 

[updated:LAST EDITED ON 05-Jun-02 AT 10:42 PM (EST)]For those of you that did the partial conversion... how long ago did you do it and how well is it still working.

By the way, the Interdynamics 2 part sealer for R134 worked very well in the wife's '94 Explorer. It stayed cool for 3 weeks before. I put the sealer in and it has been 2 months and still cold.:+