A/C retrofit information

[ecogabriel]

This should be added to the corresponding HOWTO on A/C conversion (excellent by the way)

First, settling the issue of whether Keihin compressors can be converted to R-134. Most people say they won't work but some reported them working.
Below there is a link to an EPA document that collects info from manufacturers regarding whether (and if so, which) A/C compressors should be replaced when performing a R-134 conversion

http://www.epa.gov/Region2/p2/comprssr.pdf

Long and boring, navigate to the Honda section and guess what? Honda recommends replacing Keihin compressors.

Second, the issue of lubricant of choice when converting to R-134. PAG or POE?
Compressor manufacturers (e.g. Sanden) and Acura recommend using PAG oils. The problem with PAG oils are two
a) highly hygroscopic (they absorb humidity/water like sponges) and dilluted oil does not lubricate
b) PAG oils react VERY badly with residues of R-12 including residuals suspended in R-12 oil. If you flush the system that would not be the problem; read the how to for specific instructions

Still, humidity is a problem UNLESS you choose one of the new-generation PAG oils: DEC (double-end capped) PAG.
They are modified PAGs that are almost impervious to humidity in A/C systems (you still need to remove it though) and far more resistant to R-12 residuals (they do not decompose as old PAG does)
A link below shows a graphic demonstration done by a technician on how DEC PAG behaves regarding water compared to regular PAG

http://www.autoacforum.com/messageview.cfm?catid=20&threadid=17571

DEC PAG does not cost more but you need to check closely to see what you are getting. The brand used in the comparison is available in different densities and can be bought online by about $10 for a bottle of 8 ounces (enough for 3G accords)

Incidentally, browse that website and somewhere you will find a document with refrigerant and oil capacities (and type of oil used) for EVERY single car on U.S. roads. Check the Honda section for specifics for our cars.

Enough said

[nswst8]

Good info, thanks.

[lostforawhile]

Honda started replacing the Keihin compressors before the generation was even over, there used to be a kit available that had the alternate compressor,bracket,belt,fittings and hoses. They were doing this because the Keihin unit was a piece of junk. They replaced so many under warranty, that back when the cars were new, the alternate compressor was often installed instead of the original. The Keihin isn't compatible with 134a, but even if it was, it would still be junk.

[nswst8]

I'd have to disagree Tim. I ran the kiehin compressor with R134a for almost twelve years. I finally replaced it only because I bought one of those Honda denso kits off ebay for $109 dollars and needed to take the car back to R12 because of the Texas heat. R134a retrofit just was not cutting it in Texas.

My system had its leak in the TXV/evap fitting and the compressor hose fittings. But I'm not the average car owner I always checked my pressure before and after summer season about every six months and if it needed freon I added it with oil. Probably increasing the life of the compressor. It was still pumping when I took it off.

I didn't know how much life it still had in it which is why I didn't take it back to R12 that and the fact I had the new Honda Denso A/C kit.

[lostforawhile]

I'd have to disagree Tim. I ran the kiehin compressor with R134a for almost twelve years. I finally replaced it only because I bought one of those Honda denso kits off ebay for $109 dollars and needed to take the car back to R12 because of the Texas heat. R134a retrofit just was not cutting it in Texas.

My system had its leak in the TXV/evap fitting and the compressor hose fittings. But I'm not the average car owner I always checked my pressure before and after summer season about every six months and if it needed freon I added it with oil. Probably increasing the life of the compressor. It was still pumping when I took it off.

I didn't know how much life it still had in it which is why I didn't take it back to R12 that and the fact I had the new Honda Denso A/C kit.you were one of the lucky ones, a few of these compressors were good, but most were junk. I remember people bitching about them back in the eighties even. We all know the name Keihin just says quality. :rolleyes:

[nswst8]

Yeah, that and the fact that I can work on my own A/C system.

[Importordomestic]

I use Freeze 12 in my r-12 systems. no need to change driyers clean compressors just vacuum charge and go. ive done it to 3 cars all using the keihin compressor still running to this day 1 of the cars was a 1g and it is still cold.

just didnt know if anyone else was using it.

[nswst8]

I have like 70lbs of R12 so I won't be needing anything else.

But that is what the shops in Texas were using with good results in place of R12.

[ecogabriel]

The fact that Honda itself recommends replacing Keihin compressors is telling on their ability to take on r-134; things are never black and white however as nsw's experience shows.
I am more impressed with the new PAG oils; humidity was the killer of regular PAG together with r-12 residues, but those new gen ones seem almost impervious to humidity and even to r12 residue.
I posted it because I thought it would be useful for someone trying to get his A/C back.

[nswst8]

Great info, didn't mean to highjack the thread.

[lostforawhile]

I have like 70lbs of R12 so I won't be needing anything else.

But that is what the shops in Texas were using with good results in place of R12.

if you have it in those green drums, watch the emergency vent hole, over time they start to leak and you may be left with an empty container, all the ones stored up in Atlanta have the vent epoxied over, i'm sure in an emergency the epoxy will go before the tank. the valves look almost like they are made to leak.

[nswst8]

I'll have to look at that. Thanks for the info.

[ecogabriel]

Great info, didn't mean to highjack the thread.

I never thought it that way; still the info should go with the howto on conversion to be a little more meaningful. Searching through countless thread can be frustrating.

[ecogabriel]

if you have it in those green drums, watch the emergency vent hole, over time they start to leak and you may be left with an empty container, all the ones stored up in Atlanta have the vent epoxied over, i'm sure in an emergency the epoxy will go before the tank. the valves look almost like they are made to leak.

So the R-12 tanks have built-in obsolescence devices??? :toilet:

[Dr_Snooz]

Great info! Thanks Gabriel!

[nswst8]

I never thought it that way; still the info should go with the howto on conversion to be a little more meaningful. Searching through countless thread can be frustrating.

I concur.

[ecogabriel]

I have like 70lbs of R12 so I won't be needing anything else.

I have a spare can of R-12 that I will keep for topping off my 3G. It cools quite good.
I'll have to fix the leak in my Civic and then probably convert it to r-134 because I do not want to pay a fortune to get it charged with R-12. It works wonderful with it though.
Or maybe get EPA 609 certification to be able to buy it legally and charge it.

[lostforawhile]

So the R-12 tanks have built-in obsolescence devices??? :toilet:

pretty much, back when I got my license to buy R12, my instructor explained it that way. they didn';t want people stockpiling it, so they made the containers so they would eventually leak,

[nswst8]

I have a spare can of R-12 that I will keep for topping off my 3G. It cools quite good.
I'll have to fix the leak in my Civic and then probably convert it to r-134 because I do not want to pay a fortune to get it charged with R-12. It works wonderful with it though.
Or maybe get EPA 609 certification to be able to buy it legally and charge it.

It's an easy test online for $20 http://www.epa.gov/Ozone/title6/609/technicians/609certs.html or some guys are selling it on ebay if you sign a statement of only using it to charge your own system. But for the $20 dollar fee you can buy it legally anywhere.

[lostforawhile]

It's an easy test online for $20 http://www.epa.gov/Ozone/title6/609/technicians/609certs.html or some guys are selling it on ebay if you sign a statement of only using it to charge your own system. But for the $20 dollar fee you can buy it legally anywhere.

they are changing the law,or trying to, in the future you will have to prove that you have all the recovery equipment, refrigerant scales, new gauges that require calibration, and have to be calibrated, and know how to do all the new paperwork ,before you can even get the license. basically to try and get rid of all home and small time users. the equipment cost will be so high no person will be able to afford it except shops

[ecogabriel]

they are changing the law,or trying to, in the future you will have to prove that you have all the recovery equipment, refrigerant scales, new gauges that require calibration, and have to be calibrated, and know how to do all the new paperwork ,before you can even get the license. basically to try and get rid of all home and small time users. the equipment cost will be so high no person will be able to afford it except shops

With the numbers of cars using R-12 declining steadily (except for some imports that seem to last forever) it makes no sense. When the ban was first imposed it would have been different; millions of cars would potentially be serviced and was economically feasible to do. Nowadays only car fans seem willing to spend $$$ to get their A/C back to service and some even go the r-134a route. Even r-12 recovery equipment is being sold on Ebay.

Do you know anyone in the area that may recover r-12? I need to remove it from my Civic before replacing port valves (those are positively leaking) and redo all the o-rings (probably started leaking after 16 years and 200K+ miles)?

[nswst8]

Bring it out here I can recover it. It's great side money.

[lostforawhile]

With the numbers of cars using R-12 declining steadily (except for some imports that seem to last forever) it makes no sense. When the ban was first imposed it would have been different; millions of cars would potentially be serviced and was economically feasible to do. Nowadays only car fans seem willing to spend $$$ to get their A/C back to service and some even go the r-134a route. Even r-12 recovery equipment is being sold on Ebay.

Do you know anyone in the area that may recover r-12? I need to remove it from my Civic before replacing port valves (those are positively leaking) and redo all the o-rings (probably started leaking after 16 years and 200K+ miles)?
does anything the EPA does really make any more sense? It's just like the stupid emissions in California for the small amount of old cars actually on the road, it's all about the money.

[2ndGenGuy]

I just fill my shit with propane. Works great.

[lostforawhile]

I just fill my shit with propane. Works great.

I wouldn't do that! ever see one that exploded from a leak? not a pretty sight,lots of people have died from that! AC techs have died from working on systems filled with it too. All it takes is a little leak under the hood or in the cabin and BOOM! the other thing is a lot of people run it in a mix with r12,if it burns,you're dead, that quick. Once you get a good whiff of the Phosgene gas created from it burning, it's pretty much over. I was looking up some accident statistics, and I was shocked how many people have died from R12 systems that started leaking in wrecks and the gas burned. I will never run r12 after that. Makes a good refrigerant and even better mustard gas. you'll hear people say the propane won't burn , not enough oxygen, once it leaks out of the system it's got plenty of air to mix with,. Is your ac system so leak proof that you know it will never leak again? It's a gas leak if it does,same kind of leak that levels houses.

[ecogabriel]

Hydrocarbons work great no question but the risk of fire is there. I thought about using them but discarded it after thinking of risks. There are a couple of videos on the Web about that including one in which they replicated a leak inside a car cabin with people inside... the fire was not funny at all.
Well, I might have to convert to r134a after all then...

[lostforawhile]

hydrocarbons work great no question but the risk of fire is there. I thought about using them but discarded it after thinking of risks. There are a couple of videos on the web about that including one in which they replicated a leak inside a car cabin with people inside... The fire was not funny at all.
Well, i might have to convert to r134a after all then...anyone know if the upcoming rumor about the 134a ban is true?

[lostforawhile]

Hydrocarbons work great no question but the risk of fire is there. I thought about using them but discarded it after thinking of risks. There are a couple of videos on the Web about that including one in which they replicated a leak inside a car cabin with people inside... the fire was not funny at all.
Well, I might have to convert to r134a after all then...

can you find that link? it ought to be posted here. I've seen it before and anyone who sees it changes their mind quick about propane refrigerant. I didn't know about the phosgene gas until recently, I knew about it but didn't know it was so dangerous. I have a thread somewhere about someones first hand experience. It's the one about the brake cleaner, it's the same gas, It nearly killed the original poster with one whiff.

[Dr_Snooz]

Hydrocarbons work great no question but the risk of fire is there. I thought about using them but discarded it after thinking of risks. There are a couple of videos on the Web about that including one in which they replicated a leak inside a car cabin with people inside... the fire was not funny at all.
Well, I might have to convert to r134a after all then...

It's a really easy and relatively cheap conversion. You can buy the kit from Napa, spend a Saturday doing it and you're good to go for about $100, which is a whole lot less than the cost of a single R12 charge. I recommend it heartily. I haven't noticed that it cools any less than R12 and I live in Fresno where the summers spend long weeks north of 100 deg, half the town is hot blacktop parking lots and people chop down any tree taller than 10' on principle. Once you've done it, you're no longer in that R12 no man's land either. You can buy 134 gauges from Harbor Freight for $40, cans of freon from Wal-Mart for $7, 134 oil, leak finders, etc., etc., etc. from everywhere cheap and legal. It's really not worth all the trouble that people go to to avoid converting.

[2ndGenGuy]

I was kidding about the propane thing... But I've heard of quite a few refrigerant systems running on it...

[Civic Accord Honda]

haha i was soooo glad i only filled my civics with 134 instead of propane like someone told me too... if it would of had propane id be in much pain or dead from when the compreser blew up X_X

i used 134 in the accord too and it hasent blown up yet :D tho i think it has a small leak :(

[ecogabriel]

can you find that link? it ought to be posted here. I've seen it before and anyone who sees it changes their mind quick about propane refrigerant. I didn't know about the phosgene gas until recently, I knew about it but didn't know it was so dangerous. I have a thread somewhere about someones first hand experience. It's the one about the brake cleaner, it's the same gas, It nearly killed the original poster with one whiff.

That was a couple of years ago when I was seriously considering using it. I watched the video (shot in Australia I think) on what happened with a hydrocarbon leak in a car's cabin; it was a flash of fire. The guy in the car ended up with burns (1st degree maybe?) but alive. Phosgene gas would not let us afford the luxury of a burn though.
I would use hydrocarbons in any sealed system (fridge, window A/C) no question; for a car I am kind of nervous about it.


It's a really easy and relatively cheap conversion. You can buy the kit from Napa, spend a Saturday doing it and you're good to go for about $100, which is a whole lot less than the cost of a single R12 charge. I recommend it heartily. I haven't noticed that it cools any less than R12 and I live in Fresno where the summers spend long weeks north of 100 deg, half the town is hot blacktop parking lots and people chop down any tree taller than 10' on principle. Once you've done it, you're no longer in that R12 no man's land either. You can buy 134 gauges from Harbor Freight for $40, cans of freon from Wal-Mart for $7, 134 oil, leak finders, etc., etc., etc. from everywhere cheap and legal. It's really not worth all the trouble that people go to to avoid converting.

I already got the DEC (double end capped) PAG oil because of its resistance to water and to R-12 residue; chlorine in R-12 destroys regular PAG oil while barely affecting DEC PAG. I also got a used gauge set.

The only thing I need is a vacuum pump... and time. Autozone does not carry them for rent locally so I may end up buying one and then selling it. I have not found another place from where to rent them.
I need time to replace all the seals in the lines. Fortunately the car with the A/C problem is the Civic that has quite a bit of space to work on the A/C lines; still I'll have to remove the evaporator from the cabin so there will be a bit of work. I think it will take the conversion fine.
Good to know that 3G works OK with r134; mine still works fine; I recharged it when I got it (march 2008) and the charge kept me cool this last summer too (f... cold I should add)


anyone know if the upcoming rumor about the 134a ban is true?

I heard about it too; in WI you cannot buy it (at least Ebay sellers cannot ship it to WI unless to a shop) and CA was planning to ban it.
Dunno about EPA but I suspect once a suitable replacement hits the market r134a will follow the r12 road.

[Dr_Snooz]

The only thing I need is a vacuum pump... and time. Autozone does not carry them for rent locally so I may end up buying one and then selling it. I have not found another place from where to rent them.

My brother and I went halfzees on one we bought from Napa. It was $150 and I would never consider selling it. I use the blooming thing every summer 'cause somebody always has a leak. Mostly my Mom. We had the dealer do the conversion and they botched it. Thing has leaked ever since and I cannot find the source. Anyway, you'll use it like crazy if you buy it.

[nswst8]

I can atest to this. When my neighbors find out I can work on A/C I'm busy with side jobs when the heat starts to hit the area. Florida, Connecticut, Texas and I'm sure it will be the same here in California.

My son likes the idea I can work on A/C. I have paid for my tools from the first time I did my own a/c. Ford wanted $1200 I did it for $200 and my time.

[ecogabriel]

My brother and I went halfzees on one we bought from Napa. It was $150 and I would never consider selling it. I use the blooming thing every summer 'cause somebody always has a leak. Mostly my Mom. We had the dealer do the conversion and they botched it. Thing has leaked ever since and I cannot find the source. Anyway, you'll use it like crazy if you buy it.

I know it would be a good investment; a single job done at home will pay off all the tools' cost and more :deal:


I can atest to this. When my neighbors find out I can work on A/C I'm busy with side jobs when the heat starts to hit the area. Florida, Connecticut, Texas and I'm sure it will be the same here in California.

My son likes the idea I can work on A/C. I have paid for my tools from the first time I did my own a/c. Ford wanted $1200 I did it for $200 and my time.

Side jobs? Ummhhh.... that sounds fine considering that education jobs will pay s....:toilet:

[Dr_Snooz]

I'd have to disagree Tim. I ran the kiehin compressor with R134a for almost twelve years. I finally replaced it only because I bought one of those Honda denso kits off ebay for $109 dollars and needed to take the car back to R12 because of the Texas heat. R134a retrofit just was not cutting it in Texas.

My system had its leak in the TXV/evap fitting and the compressor hose fittings. But I'm not the average car owner I always checked my pressure before and after summer season about every six months and if it needed freon I added it with oil. Probably increasing the life of the compressor. It was still pumping when I took it off.

I didn't know how much life it still had in it which is why I didn't take it back to R12 that and the fact I had the new Honda Denso A/C kit.

I think your anecdote is more proof of why you shouldn't use the Keihin and I'll explain why. The problem with the Keihins is bad design. Here's a pic of the compressor:

http://www.allacparts.com/images/products/medium/4796225686.jpg

Notice the cap held on with four torx head bolts. There are four of those caps on each side of the compressor. Below each cap is a little piston that compresses the freon. The pistons compress outward toward those caps and the only thing sealing the caps is a long thin oring. Basically, a flimsy little piece of rubber is sealing the highest load part on the compressor. There's no way for that design to last very long. Those thin orings take only so many cycles before they start leaking and I would bet that was why you lost freon. You can try to rebuild the compressor, like I did, but there are no parts or kits available. You can drive around town to all the parts shops looking for orings that might fit, like I did, and end up not finding any. Or you can take that lousy piece of garbage off the car, pitch it in the trash and put a Denso in and drive happy for the rest of your life, like I did and like you also did eventually.

I appreciate your persistence, but the Keihin is no compressor to be wasting any time on. I paid $600 for the replacement Denso from Majestic. It came with a mounting bracket and two new hoses. The compressor has worked like a champ for close to ten years now with R134. Obviously not everyone is dumb enough to put a $600 compressor into a car worth $500 but when facing the 134 conversion question, the Denso is definitely the right choice.

[nswst8]

I think your anecdote is more proof of why you shouldn't use the Keihin and I'll explain why. The problem with the Keihins is bad design. Here's a pic of the compressor:

http://www.allacparts.com/images/products/medium/4796225686.jpg

Notice the cap held on with four torx head bolts. There are four of those caps on each side of the compressor. Below each cap is a little piston that compresses the freon. The pistons compress outward toward those caps and the only thing sealing the caps is a long thin oring. Basically, a flimsy little piece of rubber is sealing the highest load part on the compressor. There's no way for that design to last very long. Those thin orings take only so many cycles before they start leaking and I would bet that was why you lost freon. You can try to rebuild the compressor, like I did, but there are no parts or kits available. You can drive around town to all the parts shops looking for orings that might fit, like I did, and end up not finding any. Or you can take that lousy piece of garbage off the car, pitch it in the trash and put a Denso in and drive happy for the rest of your life, like I did and like you also did eventually.

I appreciate your persistence, but the Keihin is no compressor to be wasting any time on. I paid $600 for the replacement Denso from Majestic. It came with a mounting bracket and two new hoses. The compressor has worked like a champ for close to ten years now with R134. Obviously not everyone is dumb enough to put a $600 compressor into a car worth $500 but when facing the 134 conversion question, the Denso is definitely the right choice.

I'm not saying that the design isn't flawed. I'm just saying that I'm not the average Joe when it comes to A/C.

Like I said I changed compressors only because I was able to get the kit you described off ebay. $109 shipped. It sat on my shelf for 2 years before I decided to switch back to R12. And instead of using a 19 year old compressor I used the brand new denso kit.

But when I took off the old one it was still holding and pumping freon. Texas heat proved to be to much for R134a conversions.

I tried to find a paralell flow design condenser to increase the the effciency of R134a but couldn't, so I took it back to R12.

To most I would recommend converting to R134a or freeze12 but for me the system was designed for R12 so I kept it R12. With me doing the work, it was cost effective.

[ecogabriel]

I read somewhere that compressors with Viton seals would not work with r134; that included Keihin.

No wonder Honda recommended replacement; anyway, there is always a "black sheep" or ns' case a white one that works against the prediction. That's the way things work I guess.

Does anyone has an idea whether the vacuum pump below may work? It seems OK for light work but I have yet to work on A/C

http://www.tooltopia.com/mastercool-90062-a.aspx

[Dr_Snooz]

That looks almost exactly like the one I have. Only better. I can't really see the connectors on it, so it might be well to make sure you'll be able to connect your gauges to it, but yeah, that looks like it will be fine.

[nswst8]

Yeah, that will just fine. A Robin air 2 stage 1.2 cfm pump will work just fine as well. I have seen them pull down a big rig truck A/C system. And is lighter and easier to store.

You can find them all over ebay.

[ecogabriel]

That looks almost exactly like the one I have. Only better. I can't really see the connectors on it, so it might be well to make sure you'll be able to connect your gauges to it, but yeah, that looks like it will be fine.

it seems to have a T-type connector for both R12 and R134a; that is pretty much standard stuff from what I've seen.
I asked because there are one-stage pumps (like that one) and two-stage pumps. The latter are said to be better because they can pull deeper vacuum. Anyway, I won't be servicing A/C on a daily basis so I may be well served with the more economical one.

[ecogabriel]

crap!!! posting twice!!!:mad: