grizbait

For folks who converted their A/C systems to R134a, did you use a drier / accumulator from a 94 or 95?

Everything I read suggests you need a drier that uses XH-7 or XH-9 desiccant to properly absorb the moisture in an R134a system. R12 systems had a different desiccant in the drier/accumulator.

(So XH-7 or XH-9 would presumably be standard in a drier originally intended to work with R134a).

I have a complete system from a 92 civic dx (going in my 93 ex). I will just use a drier from a 94-95, if the line connection ports in the drier are the same size.

I'm buying a new compressor kit anyway (compressor, o-rings, drier, expansion valve), and I've no idea if the '92 kit's drier is already built for R134a coolant. But if it's not, hoping the '94-95 drier works.

Anyone one the answer to this one?

stateofjustin

I do have one question, besides the obvious reason (cost). Why did you convert to R-134A? Honda Civics have terribly small compressors and they perform inadequately in later years (my '95 for example) as they came from the factory with R-134A. R-12 is a much better cooling agent, and more recent studies have showed that R-134A has been more damaging to our atmosphere than R-12 ever was, and that a new coolant is mandated closely in the future for all new cars.

grizbait

The cost of R12 is the primary reason. There are many opinions on cooling capabilities of one vs. the other. R134A, in a system designed for R12 will not perform like R12 would in that system. I'm expecting somewhat less performance. But all the R12 substitutes that claim to perform like R12 have their drawbacks too.

I have flushed my system completely (fully disassembled), replacing all o-rings with R134A-compatible o-rings, new condenser, compressor, and removing any trace of mineral oil in the system. I suspect I'll have reasonable results, though still not perfect, it should cool fine.

Lots of debate out there on this topic... IMO - they're all right, and all wrong, every situation is different, and often proper care is overlooked when converting to R134A.

But yes... if I could go to the auto store and buy R12 for the price of R134A... yup, that's what I'd do.

stateofjustin

You can buy it at a substantial discount on eBay. I've bought 12 cans + for repairing R-12 systems. Either way, our tiny compressors suck and they really don't do a good job of cooling off the interior. My original recommendation stands, the re-man unit usually has everything you need, or tells you which oil to use with that specific compressor, if they aren't pre-filled. I've replaced a bunch of compressors and this has always been the case. No come-backs.

strategy400

You should buy a new drier regardless.
The R134a is fine but you need to completely flush the old system of all the old R12 oil or you will develop acid in the system and ruin everything.
The key to getting cold AC is a pristine clean system (no moisture or contamination), the exact amount of oil and exact amount of refrigerant.
This is going to be hard with a hybrid system because you don't know the exact amount, and R134a requires a different amount than R12.
I would have said stick with the R12 system because:
They get colder.
You can get specs for your system.
You don't have to flush the old oil out.
R12 is more available and cheaper now.
People hoarded that stuff when they banned it but now R12 cars are becoming rarer and people still have cases of the stuff in their garage. Search ebay right now, its almost as cheap as R134a. You only need 2-3 cans to charge.

stateofjustin

strategy400,

That information is a little old, that was a big concern right at the beginning
when they first started doing conversions. The oil itself does not retain any
of the R12, and thusly it is not a problem.

The order of operations is:

Using an R12 Reclamation/Charger, vacuum the system to negative pressure.
(this removes all the R12 gas that would interact with the R134A gas. The oils
don't retail enough of the gas for it to matter). Doing this leaves you ready to
crack open the system.

You would install your new R134A fittings to replace or attach to your R12 High
and Low side ports.

Remove the receiver dryer and replace it. It doesn't have to be a special unit, the
stock one is fine since all the R12 was removed. You want to put 3-4 ounces of the
recommended oil (PAG oil or Mineral oil) into the receiver dryer before installing it (it
and the compressor retain most of the oil in the system).

Charge the system with R134A, and enjoy your horrifically less efficient cooling system.
At idle you will have virtually NO cooling at all.

OR

Buy R12 on eBay, and the can tap and tube so that you can recharge with your
intended refrigerant. Keep in mind that dispersing R12 into the atmosphere is
damaging, and to do it with some R12 still in the system you need a gauge set
and know how to use it. If empty you simply charge with as many ounces/pounds
as your car requires.

My '95 Civic has R134A from the factory... I'm tempted to save weight and remove
it even in Southern California, that's how badly it sucks.

strategy400

I live in the desert, 110 during the summer and my R134a system spits ice cubes out of the dash.
3-4 oz. of oil is almost enough for the entire system. Be careful to rid the system of all the oil before adding that much or risk ruining your compressor.
Perhaps you have overcharged your system with oil and that can account for the poor performance of your R134a system.

stateofjustin

You have a Del Sol... which means you have like 1/3'rd of the air inside your cabin than my car does, so I'm not surprised it is more than adequate for you.

As to *my* R134A levels, they are exactly where they are supposed to be, as are my gauge readings. The compressor and system is simply too small for
the car. My '97 VW Golf, similar interior size had a compressor 3 times bigger. Now THAT was great AC, even for R134A.

http://www.flickr.com/photos/30955309@N06/8427063073/http://www.flickr.com/photos/30955309@N06/8427063073/ by http://www.flickr.com/people/30955309@N06/, on Flickr

Some more realistic numbers on the oil. I must have been daydreaming of better air conditioning at the time I was typing since I typed 3-4 when I meant 1/3-4.
Anyway, these are straight Honda spec from my 92-95 Service Manual.

strategy400

39 degree vent temps would be fine for any size cabin. Much colder and you'll have a block of ice in your dash.
Again the critical points of cold AC:
Clean mechanically sound system (no moisture/contamination).
Draw a deep vacuum.
Charge with proper type and exact specified quantity (weight) of both oil and refrigerant.
Are the specs you posted for R12 or R134a? The oil quantities are identical with R12 specs. I'm too lazy to look up the oil P/N.

stateofjustin

Where did 39 degrees come from... your car? I know mine doesn't blow anywhere near
that cold, even in the shade, with a long thermometer in the vent.

The specs are for 92-95 Civics, so since there is no alternate table, my guess is that all
92-95 Civics are equipped with R-134A.

strategy400

I want to say they started switching from R12 to R134a in '94. Yes I get 39 degrees with a digital thermometer in the vent. I picked my cousin up from the train station last summer and after a few miles he remarked that his ears hurt from the cold.

99FormulaM6

All 92s were R12 and in 93 they started the switch, so some 93s had R12 and the rest were R134 and all 94+ are R134.

stateofjustin

Got it. Good information to have. Mine doesn't have an alternate table because it's the factory manual for my specific year ('95).

I'm jealous of the A/C performance in the Del Sol though, in a full size Civic like mine, the AC isn't good enough for the driver or passenger, let alone anyone in the back seats. Just too much airspace and too small a system for it. Add taking out the rear seat and you have the trunk's airspace to remove heat from too. It's just way too much. I wonder how many pounds the entire system weighs... I would get a pretty serious weight reduction I bet if I removed it all. Would certainly improve gas mileage, then again, so would driving around on a quarter tank all the time.