R12 to R134a conversion....

[xaxis360]

This forum is interesting. There are so many conflicting views on our A/C. Since Honda is a multi-million dollar company who claims responsiblity for desiging the A/C systems we are arguing about, it may be a good idea to reference this interesting TSB that was issued in the mid-90's discussing R-12 to R-134a conversion.

"Converting R-12 A/C Systems to R-134a"

(You need Adobe Acrobat to see it)

Anyways, there are some interesting points in the article.

First, it dispells the rumours on here that you have to replace anything except the high/low valves with 134 compliant ones (if the system is working properly and hasn't been opened to the atmosphere)

Second, if you have a 90-91, you may have to buy a new receiver line if yours is mounted on a "block" and points to the alternator because the new valves will not allow clearance for the equipment to connect.

Third, it instructs the techs to subtract 1 2/3 oz. of the systems R-12 capacity when filling with 134.

Fourth, the system appears to run at a higher pressure with R-134a refrigerant.

Here's some more information I've heard repeatedly from people who work on automotive A/C systems...

NO A/C system is "leakproof" They all leak to some degree. Over time, an A/C system (especially on a car) will leak enough refrigerant out to eventually need recharged. With this in mind, if your system is not in top-shape, installing 134 will not be a good idea because it runs at higher pressures in the system, and 134a molecules are in fact smaller than R-12.

If your R-12 system is just "not blowing as cold" I would seriously consider finding an older garage that still carries it and ask for a top-off. I went to a local shop, and the guy only charged me $40 a pound! Granted, not all people know the going rate for R-12 and it is indeed very expensive. It only needed a half-pound anyways. It's been two years and its worked great ever since.

[xaxis360]

One more thing, there is a Service News article I read about a year ago.

It mentioned to make sure the schrader valves on your A/C system are sealing properly because they can go bad or not seat properly. It went on to say that the schrader valves alone aren't good enough to keep the system sealed.

It said it's very important to make sure you have the valve caps that come from the factory screwed on. Supposeldly, they are designed to seal the system tightly, and hold refrigerant in even if a schrader valve goes bad.

[xtremeskier97]

My low side schrader valve was bad....and I knew it was. He replaced it. System is charged and feels MUCH better! The only thing is, is when its sunny and hot out, we have to keep the thing on full blast just to keep us all cool. Our windows are even tinted to Louisiana state law specs. Now..once the sun goes down, but still hot out, we have to turn it down and notch and it keeps us nice and cool.

[xaxis360]

The biggest push from Honda back in the day (prolly still is) was to keep your car on recirculate for good A/C performance. They may have compensated for it by now, but I always remember them preaching that to people when they would complain about the A/C not being cool enough.

[evol90accord]

My low side schrader valve was bad....and I knew it was. He replaced it. System is charged and feels MUCH better! The only thing is, is when its sunny and hot out, we have to keep the thing on full blast just to keep us all cool. Our windows are even tinted to Louisiana state law specs. Now..once the sun goes down, but still hot out, we have to turn it down and notch and it keeps us nice and cool.

sounds about right. I've read some things about aftermarket evaporators that help this issue, but thats one more thing I didn't want to replace especially after charging the system.

First, it dispells the rumours on here that you have to replace anything except the high/low valves with 134 compliant ones (if the system is working properly and hasn't been opened to the atmosphere)

Second, if you have a 90-91, you may have to buy a new receiver line if yours is mounted on a "block" and points to the alternator because the new valves will not allow clearance for the equipment to connect.

Third, it instructs the techs to subtract 1 2/3 oz. of the systems R-12 capacity when filling with 134.

Fourth, the system appears to run at a higher pressure with R-134a refrigerant.

Here's some more information I've heard repeatedly from people who work on automotive A/C systems...

NO A/C system is "leakproof" They all leak to some degree. Over time, an A/C system (especially on a car) will leak enough refrigerant out to eventually need recharged. With this in mind, if your system is not in top-shape, installing 134 will not be a good idea because it runs at higher pressures in the system, and 134a molecules are in fact smaller than R-12

Good info, xaxis. "(if the system is working properly and hasn't been opened to the atmosphere)" I reiterate, most people wouldn't bother doing ANY of this unless there was a problem. However, since xtremeskier started this thread saying he had already replaced the compressor and accumulator/drier, it was a good idea to recommend all this other stuff to him. Much like a timing belt job, its not *necessary* to replace all the waterpump, idler pulleys, or seals at the same time its just highly *recommended*. Again, good info and interesting points. I think I've said everything I can on this subject now

[xtremeskier97]

Definitely a good thread. Good info.

Thanks guys.

[reidc]

Help???

OK- kids-
I've got no information to add to this discussion, but I do ask a wee bit o help.

I just added R-134 to my Pathfinder as it was on the low side(it was 134 from the factory), and now seems great- I should find out tommorrow during commute.

When I got my Accord last summer- the guy had it converted about a month before I bought it. By the time I looked at it- it was already dead. So I figured I'd grow some balls tonight and try it on my Accord.

The low side valve is located right next to the battery between battery and center of hood(1992 EX). There was no cap there, and I could not find the high side valve, so I figured this one had to be the one(and it fit!!!). I was extremely surprised to hear the compressor kick on after I'd had the button pressed to charge. However- the guage did not go much above 0, and I stopped the process a few times to shut off and reconnect to get a pressure check before adding more. When can appeared empty(it was not full when I started)- I went to reach for the disconnect, and before I got my hand there I heard a hissing- pretty loud actually and the shreader valve seemd to have broken. I lost whatever charge I put in there.

Could this be why it died before I bought this thing, or could I have caused further damage? I am sure this valve will unscrew fairly easily and I can buy another?

Thanks,
Chris

[xtremeskier97]

My schrader valve on the low side was bad also. Had to replace it. This very well could be the reason your car was empty. They are cheap and easy to replace (with the right tool).

[evol90accord]

Schrader valves do go bad. The tool to remove them is like 2 bucks and the valves are cheap too. There are special adapters for r134a though, so look into that. Good luck.

[John Conner18]

my car still uses R12. How is that dumb? Its what all Honda's were filled with until 1994?????

ya same here mines is a 91

[esskater892]

anybody have an idea of the pressure to charge it to? i am doing the retrofit do it nice or do it twice from the diy section on here but there is no guide telling what the actual pressure should be.

[bobbycos]

This forum is interesting. There are so many conflicting views on our A/C. Since Honda is a multi-million dollar company who claims responsiblity for desiging the A/C systems we are arguing about, it may be a good idea to reference this interesting TSB that was issued in the mid-90's discussing R-12 to R-134a conversion.

"Converting R-12 A/C Systems to R-134a"

(You need Adobe Acrobat to see it)

Anyways, there are some interesting points in the article.

First, it dispells the rumours on here that you have to replace anything except the high/low valves with 134 compliant ones (if the system is working properly and hasn't been opened to the atmosphere)

Second, if you have a 90-91, you may have to buy a new receiver line if yours is mounted on a "block" and points to the alternator because the new valves will not allow clearance for the equipment to connect.

Third, it instructs the techs to subtract 1 2/3 oz. of the systems R-12 capacity when filling with 134.

Fourth, the system appears to run at a higher pressure with R-134a refrigerant.

Here's some more information I've heard repeatedly from people who work on automotive A/C systems...

NO A/C system is "leakproof" They all leak to some degree. Over time, an A/C system (especially on a car) will leak enough refrigerant out to eventually need recharged. With this in mind, if your system is not in top-shape, installing 134 will not be a good idea because it runs at higher pressures in the system, and 134a molecules are in fact smaller than R-12.

If your R-12 system is just "not blowing as cold" I would seriously consider finding an older garage that still carries it and ask for a top-off. I went to a local shop, and the guy only charged me $40 a pound! Granted, not all people know the going rate for R-12 and it is indeed very expensive. It only needed a half-pound anyways. It's been two years and its worked great ever since.

Link dead now ,

Could use that TSB now

[93cb7h22a]

Dont use r134a, go buy some pag oil and 3cans of dustoff at sams club for $9.99 boom you'll blow 40 degrees Fahrenheit all day dont waste money on $15-20 cans of 134

[93cb7h22a]

anybody have an idea of the pressure to charge it to? i am doing the retrofit do it nice or do it twice from the diy section on here but there is no guide telling what the actual pressure should be.

With compressor on 25-35 on the low pressure side