The (hopefully) official R134a conversion thread

[clandr1]

I'm starting this thread for a couple of reasons: one, to get your feedback as I begin/perform my A/C conversion from R12 to R134a, and two, to guide future CK5 members through the conversion process if they choose to do it.

So far I have ordered the following parts for my rebuild:

Sanden 4864 compressor (ear mounts and GM pad mount) from eBay $175
Gasket/o-ring kit (P/N 801750) from NAPA $5.49
Self adjusting orifice tube (P/N 38902) from O'Reilly $20.99
134a compatible dual flow condenser (P/N 2083) from O'Reilly $109.99
Receiver accumulator/drier (P/N 208542) from NAPA $22.49
Custom lines (from Airpro Air in Mesquite) longer than stock to account for the longer Sanden compressor: $125 for the lines, and $20 for the GM pad adaptor

I started using MaxPF's thread "Wintertime AC" where he recommends a Sanden compressor that is more efficient than the standard R4 pancake compressor. It will take a little bit of trial and error when fitting it (need bolts, nuts, and possibly spacers) but it can and has been done.
http://coloradok5.com/forums/showthread.php?t=193200

Regarding installation of the Sanden compressor:

For serp setups any 6,7, or 8 will work, but only the first 6 grooves will be used. You will need some 3/8" bolts to hold it in (two 1-1/2" and two 2" long for serp belt setups), as well as some hardened SAE washers, stover lock nuts, and two .312" thick spacers (or a stack of washers). Assembly is straightforward and obvious - just make sure the pulleys line up and that the connections aren't interfered with bu other stuff (that is why I have the compressor rotated nearly 90 degrees toward the passenger side).

I will update in another 2-3 weeks when I'm able to begin replacing the items, and I'll take copious amounts of photos along the way from removal, flushing, installation, and charging.

 

[imiceman44]

If you are replacing all these items, I would first blow out all the hoses and the condenser with air, then there is a can for flushing the system for conversions run that in there and install the parts and vacuum.
Technicaly you are supposed to blow nitrogen thru so you do not get condensation inside but I use air then vacuum.

 

[Fordum]

R134 has more heat capacity than R12, which is why conversions usually fail.
OK, thats not what I meant to say.
The extra heat capacity is what causes most failures.
Thats better.
Anyway, the new condenser is the main thing. You have to get rid of the extra heat that you are going to encounter.
But, don't forget, this is also going to cause more heat to be dumped into your engine's cooling system.
So, take a minute to make sure that its up to par. If the truck was running on the hot side before, its going to get worse when the AC is on.

Also, good luck with the variable orifice. Its a great idea, and may work fine. But I bought one back when they first came out, and it did not stand up.
It stuck in one position, and cause problems.

I finally had to go back to the standard one.
If yours works, let me know, because I would love to try another one.

 

[y5mgisi]

Subscribed!

 

[77 casa grande]

At this point I would replace the hoses and evap core. Why take a chance of a contamiating your new parts. Flushing is not 100% compleate, or risk a leak in a 20+ year old evaporator.
Do it once, do it right. GMO

 

[clandr1]

R134 has more heat capacity than R12, which is why conversions usually fail.
OK, thats not what I meant to say.
The extra heat capacity is what causes most failures.
Thats better.
Anyway, the new condenser is the main thing. You have to get rid of the extra heat that you are going to encounter.
But, don't forget, this is also going to cause more heat to be dumped into your engine's cooling system.
So, take a minute to make sure that its up to par. If the truck was running on the hot side before, its going to get worse when the AC is on.

Also, good luck with the variable orifice. Its a great idea, and may work fine. But I bought one back when they first came out, and it did not stand up.
It stuck in one position, and cause problems.

I finally had to go back to the standard one.
If yours works, let me know, because I would love to try another one.

Good points, but my engine cooling is 100%. New radiator, t-stat, and hoses approximately 24 months ago. It never runs hot: for example, last summer when the A/C was working, I went on a 2 hour highway trip, then poked around some land all day (A/C going the whole time) and never had overheating issues.

At this point I would replace the hoses and evap core. Why take a chance of a contamiating your new parts. Flushing is not 100% compleate, or risk a leak in a 20+ year old evaporator.
Do it once, do it right. GMO

Normally I would agree with you, but most of the threads I've read on A/C conversion shows no correlation between using old parts vs. installing new when it comes to successful cooling (project success), with the exception of the compressor and condensor which are absolutely necessary to replace. Replacing the ancillary components is not completely necessary, and in keeping with a budget project theme I will leave the hoses and evaporator unless it is discovered that they have failed (are leaking).

 

[jeff in co]

I did this whole conversion last year and replaced everything except the metal tubing attached to the fenderwell. And I cleaned and flushed that out real well before tying it all together.

It worked out great and my AC is as cool as a cucumber.

One of the more difficult things to find was the black hoses that fit my 89'. Apparently the ones from Advanced Auto, etc use the older one so the hoses go a different direction than mine. I'll look around for the part number for you......

 

[clandr1]

I did this whole conversion last year and replaced everything except the metal tubing attached to the fenderwell. And I cleaned and flushed that out real well before tying it all together.

It worked out great and my AC is as cool as a cucumber.

One of the more difficult things to find was the black hoses that fit my 89'. Apparently the ones from Advanced Auto, etc use the older one so the hoses go a different direction than mine. I'll look around for the part number for you......

Good to know it is doable.

Did you have any other difficulties I should be on the lookout for? As I mentioned above, currently the plan is to replace on the drier, orifice tube (hopefully the adjustable version doesn't give me problems) and compressor, leaving the rest of the existing system in the truck, assuming it is functional.

 

[jeff in co]

Good to know it is doable.

Did you have any other difficulties I should be on the lookout for? As I mentioned above, currently the plan is to replace on the drier, orifice tube (hopefully the adjustable version doesn't give me problems) and compressor, leaving the rest of the existing system in the truck, assuming it is functional.

I replaced everything really. Then brought it into the dealership to evacuate and charge the system. Also wanted them to handle the proper amount of oil going into the system. I got it close and then they did the rest.

It is more expensive replacing everything but b/c this is a 23 year old truck and who knows how the existing system will be.....I didn't want to chance ruining a brand new compressor because I didn't flush out the old equipment good enough or the old equipment just failed.

 

[Fordum]

I forgot to mention about the hoses.
Remember I go back way before the first R134, so I have seen all the missteps, problems, what have you.
When they first started changing over, the hoses would do fine for a while, then start leaking out the hose its self, not where the fittings were attached.
People said that the new gas was smaller and would seep out the pores of the hose, so you had to go with new type hoses.

But, it was discovered that the problem was with the oil. The old oil soaked into the inside layer of the hose, and sealed it.
When that oil was flushed out, the new oil did not do that. As soon as the small amount of original oil leached out of the hose, it started leaking.

But, the problem was erratic. Some older hoses leaked, and some didn't. I don't know the price of 134 these days, but if it has not gone too high, it might be worth the gamble.

 

[imiceman44]

I forgot to mention about the hoses.
Remember I go back way before the first R134, so I have seen all the missteps, problems, what have you.
When they first started changing over, the hoses would do fine for a while, then start leaking out the hose its self, not where the fittings were attached.
People said that the new gas was smaller and would seep out the pores of the hose, so you had to go with new type hoses.

But, it was discovered that the problem was with the oil. The old oil soaked into the inside layer of the hose, and sealed it.
When that oil was flushed out, the new oil did not do that. As soon as the small amount of original oil leached out of the hose, it started leaking.

But, the problem was erratic. Some older hoses leaked, and some didn't. I don't know the price of 134 these days, but if it has not gone too high, it might be worth the gamble.

Yeah I remember the same thing, they said the hose needs to be changed because the pores are big for the new gas, but now they have additives in the gas and oil to work with older hoses.
I have successfully changed over many cars and trucks and most go on for a long time, some require topping off after 3-4 years, which is fine by me, I check them every year and as long as they are in the right range I leave them, once they get to the min, I add a can.
One car I had converted long ago needed a can every year, until recently I guess since now they add stuff tp the oil and gas so now it's fine.

 

[Fordum]

Yeah, something in the back of my mind tells me they changed the formula of the oil
( PAG oil?) that they used and it helped a lot.
Also, they changed the specs on the conversion.
When they first started doing it, the rule was any trace of the old oil would cause problems, so people did heavy flushes.
Later they said just get as much loose oil out as you can and what is left is OK. So that probably helped seal the hoses too.

To tell the truth, if I were converting one personally for my exclusive use, I would probably use one of the Freeze12 type mixes.
I have used some once or twice, with real good results. Since its a blend, you must charge it as a liquid, and if you have a leak, you have to pump out and discard all of it and start over, but it works great.

And, while its flammable, it has an odor to warn of a leak, its not any more dangerous than a natural gas engine, and requires a lot less retrofitting than R134. Plus its less toxic.

But that is a personal decision, and I would probably not charge a friend's car with it. And certainly not one that might be serviced by someone else.
If they do not know what is in it, they can contaminate their stock.

 

[imiceman44]

I don't know about too much to convert, I got the conversion kit which is 2 adapters for low pressure and high pressure ports and the cans containing the r134 and oil and additive in the same can.
I vacuumed for a few minutes then charged it till I got the right pressure.
Can't get easier than that.
Never changed anything either, unless there was something wrong, bad parts etc...

Yeah, something in the back of my mind tells me they changed the formula of the oil
( PAG oil?) that they used and it helped a lot.
Also, they changed the specs on the conversion.
When they first started doing it, the rule was any trace of the old oil would cause problems, so people did heavy flushes.
Later they said just get as much loose oil out as you can and what is left is OK. So that probably helped seal the hoses too.

To tell the truth, if I were converting one personally for my exclusive use, I would probably use one of the Freeze12 type mixes.
I have used some once or twice, with real good results. Since its a blend, you must charge it as a liquid, and if you have a leak, you have to pump out and discard all of it and start over, but it works great.

And, while its flammable, it has an odor to warn of a leak, its not any more dangerous than a natural gas engine, and requires a lot less retrofitting than R134. Plus its less toxic.

But that is a personal decision, and I would probably not charge a friend's car with it. And certainly not one that might be serviced by someone else.
If they do not know what is in it, they can contaminate their stock.

 

[nsxxtreme]

subscribed. I want to do this also.

Couple questions.
1. what belts are you using, vdrive, serpantine?
2. One complaint I always had was the amount of air that comes out really sucks for how big the cabin is. Doing anything to address that?

 

[Kainedogg]

Subscribed.

 

[imiceman44]

subscribed. I want to do this also.

2. One complaint I always had was the amount of air that comes out really sucks for how big the cabin is. Doing anything to address that?

Blazer or truck?
Or is it a suburban?
On the truck it's pretty good, but for a blazer or crew cab, it's not enough for the size of the cabin.
On a suburban or a Van (and I have both) it's nice that you can have the dual units one in the front and one in the back.

 

[clandr1]

subscribed. I want to do this also.

Couple questions.
1. what belts are you using, vdrive, serpantine?
2. One complaint I always had was the amount of air that comes out really sucks for how big the cabin is. Doing anything to address that?

1. serpentine setup as it came from the factory

2. Whatever is in my dash that directs the air to the floorboard, dash, or defroster vents sucks ass. I've removed the glovebox and zip tied the actuator arm to full open, so all the air pours out of the dash vents. Before it would be split between the dash and floorboard even on "max A/C". I'm sure I have a vaccum loss somewhere or bad actuator, but for 5 minutes and a zip tie I just do that for the summer, then cut it off when it starts getting colder so the heat comes out on the floorboard. Perhaps looking for a higher volume blower motor/fan would be a good start, but in my opinion the volume coming out of the vents is adequate for my application. I don't often have passengers in the back seat, but even if I do, aiming the middle vent to the rear should keep them from sweating

 

[nsxxtreme]

Blazer or truck?
Or is it a suburban?
On the truck it's pretty good, but for a blazer or crew cab, it's not enough for the size of the cabin.
On a suburban or a Van (and I have both) it's nice that you can have the dual units one in the front and one in the back.

You described the problem exactly. I think the unit they used in the blazer and other vehicles is the same one use in the trucks. For a truck with a small cabin probably ok but anything bigger then a truck and it reallys sucks!!!!

 

[nsxxtreme]

1. serpentine setup as it came from the factory

2. Whatever is in my dash that directs the air to the floorboard, dash, or defroster vents sucks ass. I've removed the glovebox and zip tied the actuator arm to full open, so all the air pours out of the dash vents. Before it would be split between the dash and floorboard even on "max A/C". I'm sure I have a vaccum loss somewhere or bad actuator, but for 5 minutes and a zip tie I just do that for the summer, then cut it off when it starts getting colder so the heat comes out on the floorboard. Perhaps looking for a higher volume blower motor/fan would be a good start, but in my opinion the volume coming out of the vents is adequate for my application. I don't often have passengers in the back seat, but even if I do, aiming the middle vent to the rear should keep them from sweating

Thanks I have the basterdized version of serpentine and vbelt setup. GM always like to do things half assed. I need to switch to the serpentine setup.

 

[imiceman44]

Thanks I have the basterdized version of serpentine and vbelt setup. GM always like to do things half assed. I need to switch to the serpentine setup.

So you have the serpentine setup but the A/C is V belt right?
Yeah, they could have done it seperate but ribbed instead of Vbelt, and that is what I would do if I were you.
I like having the A/C seperate so if you seize a compressor, you don't lose everything.