A/C question

[Live4Boost]

I just recently bought an 89 quest that I am restoring and I was wondering if they sell a conversion kit for our a/c systems to run on the new stuff?

[JAinsworth]

Yes, you can get it converted to r-134.

Jimmy

[intense98rt]

You can buy the fittings at the auto part stores. Take it to a shop, have them remove the r12, flush the system and add it the new oil and r134a.

[notfried]

why would you want to?an R-12 car with a proper working a/c system full of freeze-12, not R-12, will be way cooler than any 134 system could ever think of being

[Contsi]

Appears to be different options here, Is the best option for a functioning a/c system the freeze-12?

Any downside as opposed to R134 retrofit? Any special requirement for adding freeze-12, adapter etc?

 

Thanks

[notfried]

Appears to be different options here, Is the best option for a functioning a/c system the freeze-12?

Any downside as opposed to R134 retrofit? Any special requirement for adding freeze-12, adapter etc?

 

Thanks

 

you don't need to do anything to make your a/c compatible with freeze-12, just have a shop evacuate the system, pull a vacuum on the system, and then charge it.

 

running a 134 system is a lot cheaper, though since R-134 ranges from 5.99 a can to 11.99 a can where as freeze-12 is about 15 bux a can and up

[newquest86]

well i am certified for mobile ac systems and r134 retrofits why would you not want to retrofit to 134 ? its available everywhere, it works very well when done right ,and colder than freeze 12 which is garbage read up about it , i retrofitted my conquest last summer to 134 and have done many retrofits over the years the problem is most people are afraid of change and listen to other peoples headaches and get discouraged and most of all most people dont know how to retrofit or use 134a my duct temps are colder than any r12 or freeze 12car out there . just my .02

[notfried]

well i am certified for mobile ac systems and r134 retrofits why would you not want to retrofit to 134 ? its available everywhere, it works very well when done right ,and colder than freeze 12 which is garbage read up about it , i retrofitted my conquest last summer to 134 and have done many retrofits over the years the problem is most people are afraid of change and listen to other peoples headaches and get discouraged and most of all most people dont know how to retrofit or use 134a my duct temps are colder than any r12 or freeze 12car out there . just my .02

 

I'm just sharing my experience with quests and 134 and I don't care what anyone uses...and I'm an ASE certified master tech, whoopty-doo. My dog can go out and get certified for a/c.

 

I have had better experiences with freeze-12 than 134 in older vehicles that have a/c systems that work properly. I don't need to read others opinions on 12 when I have my own. 34*

 

Like I said, I don't care one way or another. Everyone has their preference...I'm just givin' other options

[Contsi]

well i am certified for mobile ac systems and r134 retrofits why would you not want to retrofit to 134 ? its available everywhere, it works very well when done right ,and colder than freeze 12 which is garbage read up about it , i retrofitted my conquest last summer to 134 and have done many retrofits over the years the problem is most people are afraid of change and listen to other peoples headaches and get discouraged and most of all most people dont know how to retrofit or use 134a my duct temps are colder than any r12 or freeze 12car out there . just my .02

 

Thanks for the info - Is it possible for you to outline here the correct way to convert my 87 Conquest TSi to use 134 and the cost involved.

Anything I should ask a tech to be sure he knows what he is doing.

[newquest86]

yes every moron has their opinion

[mikec]

First, repair whatever caused the original a/c leak/failure before recharging... otherwise your new refrigerant will just leak out again. Most a/c leaks will accumulate a wet/greasy mess. Look at the joints in all of the a/c hoses/pipes for messes. If grease is everywhere (as is common on older cars) then you'll have to clean all the joints and re-fill one more time. A pro shop might do exactly this - with a ultraviolet (UV) dye added. Simple Green works well to cut through most engine grease by the way.

 

Usually, when I have a leaking o-ring seal on a car a/c system, rather than fixing only the bad joint, I replace every o-ring in the system: if one is old enough to have died, the others are probably on their last legs too. I'd rather do the work once and not have to worry about leaks for another 10 years. I often replace the rubber hoses too.

 

O-rings eventually fail and leak. The hard rubber a/c hoses often get hard/brittle at their ends, where they fit into those crimped-on caps. If you've never seen how a high pressure hose fitting works, it's basically:

* Metal pipe threaded on one end (with the o-ring trapped in there) to mate with the another pipe.

* That metal pipe ends in a barbed pipe.

* The rubber hose fits tightly over the barbs

* Instead of using a typical hose clamp, a cylinder shaped metal piece is used. This fits over the end of the hose; a special tool crimps grooves into this cylinder... the grooves are spaced similar to the barbs of the inner pipe. This makes a really tight seal.

 

Unfortunately, when the rubber gets old and dries out, it shrinks a bit so the outer cylinder doesn't clamp as well. Flexing the hose (which happens when the engine "leans" as you rev it or start it) exacerbates this problem. Often you can "test" a hose by flexing it near the outer cylinder, listening for leak sounds.

 

There are a few o-rings in the evaporator core - the radiator-like part under the dash (typically) that actually cools the air. These o-rings aren't subjected to engine bay temps so they fail far less often - which is fortunate because replacing them is a big labor expense. You may gamble on not replacing them when doing all the others... it's a pretty safe bet. Also under the dash on StarQuests is the "expansion valve" which is what makes the high pressure refrigerant jump down to a low pressure - and jumping to a really low temperature too. The factory StarQuest R-12 specific part works okay for R-134a but you can buy aftermarket ones that are designed for R-134a. Pay attention to the "bulb" part and how it's hog-tied to one of the refrigerant hoses; you'll want to make sure the bulb on the new expansion valve is installed the same way.

 

To do the job yourself, and to do it right, you'll need to be able to:

1: safely/properly unbolt each joint. Usually simple - just use two wrenches just like any plumbing job. Take the hoses & pipes out where possible and hang them vertically - this will drain the old R-12 compatible oil out of the system.

 

2: If the rubber hose joints leak, take the hose to an a/c shop, NAPA, etc. and have the rubber part replaced. They'll slice the metal cylinder sleeve apart, replacing the sleeve and the hose with new "barrier" style hose - required for today's R-134a refrigerant but compatible with the old R-12 freon as well. They'll re-use only the original barbed fitting/pipes on each end. Old rubber a/c hoses are too porous for the smaller R-134a molecules... though once coated with R-12 and oil that often seals the old style hoses pretty well. That's why folks that don't fully convert get 2=5 years out of a R-134a charge anyway. Again though I like new, pliable hoses instead of old brittle ones that may fail any day.

 

3: Use R-134a rated o-rings - basically blue or green ones. They'll work with R-12 as well. The black ones are too porous for R-134a. I'd replace the receiver/dryer too; they have a finite lifetime. That's the silver canister strapped to the nose of the car near a headlight. It "filters" crud from the refrigerant... so it's easy to see why it eventually is used up.

 

4: when re-assembling, wet the o-rings with a/c system oil as you install them. Otherwise they can rip/tear as you tighten the joints. R-134a retrofit kits will include a couple of adapters to screw onto the original a/c service fittings (the fittings where you hook refrigerant cans and gauge sets). R-134a fittings are a different size from R-12 --> to prevent accidental miss-matching refrigerants. You'll need to remove (unscrew) the valve tip from the original fittings first.

 

5: with the system totally assembled, connect an a/c pressure gauge set (two gauges).

 

6: Ideally the system would be flushed out with nitrogen. This helps flush out any moisture from the atmosphere that might have gotten into the system. Shops do this; many home mechanics can't/don't because they don't have nitrogen tanks handy.

 

7: Pour or inject the proper quantity of a/c compressor oil into the system. There are two types of oil: one for the old R-12 refrigerant and one for R-134a. Use the one that matches the refrigerant... even if your car WAS R-12 originally and you're converting it to R-134a you'll need oil compatible with R-134a. The oil is "picked up and carried by" the refrigerant; R-134a won't carry the older oil. Pour the new oil into the gauge set's hose going to the "discharge" or "high pressure" side of the compressor.

 

8: Apply a vacuum pump to the system and fully evacuate it - takes a minimum of half an hour in most cases. Then shut off the vacuum pump. Let the system sit for some time - hours if possible - and verify the gauges don't budge. If they move, you still have a leak. If you didn't use nitrogen, run the vacuum pump much longer - it takes a while to get all moisture out of the system under vacuum.

 

9: Connect the gauge input hose to a source of refrigerant. Leak a little of the refrigerant where the hose joins the gauge set (loosen the fitting slightly while the refrigerant tank is open) to flush air out of that hose. Then re-tighten the input hose. Open the gauge valves and allow refrigerant to flow from the pressurize refrigerant tank into the car. Pro shop equipment will measure the weight and/or volume of the refrigerant so they know how much went into the car. You'll probably just count cans of refrigerant. If using the cans, stick them into a pan of hot (but not boiling hot) water; that'll raise their temps and thus the refrigerant pressure in the can so you can get more out of each can.

 

10: once one can is in the system, close the gauge valves, fully open the needle valve on the refrigerant can, then remove the can, and replace it with a new/full one.

 

11: Turn on the engine and set the a/c to max cool, lowest temperature, full recirculate. There should be enough pressure in the system for the a/c compressor to engage: StarQuests (like most cars today) will NOT run the compressor if the refrigerant pressure (and thus refrigerant quantity) is too low because no refrigerant flowing through the system = no oil flowing with the refrigerant either.

 

12: stick a thermometer into a center dash vent. Monitor the air temps coming out of the system as you fill with the second refrigerant tank.

 

13: the factory service manual for the car, or the manual that came with the gauge set, will show the proper "suction side" and "discharge pressure" for your a/c system as a function of outside/ambient air temperatures. Use these as a guide... adding refrigerant until your gauges indicate those pressures. You'll probably need a helper to hold the engine RPMs up a little. Watch the thermometer we stuck into the dash vents... if that temp starts rising, the system has just passed "enough" refrigerant.

 

Factory R-134a systems use a larger condensor (the a/c radiator in front of the engine) than an equivalent capacity R-12 system. You can either replace the stock condensor with a thicker one (if you can find one...) or tweak the electric fans. I re-wired one car's pusher fan to run whenever the a/c system is ON; on a stock StarQuest it only runs when the a/c is working extra-hard. On my car I didn't bother with this and the a/c works fine anyway.

 

mike c.

[Edde]

You can buy r12 on evilbay. But it's pricey.

[TexasQuest]

I thought you had to have a special certification to buy r-12?

[87TsiOwner]

No but you can only buy small cans of it.

[Edde]

You have to state that you're buying it for resale to a qualified tech. http://www.starquestclub.com/forum/public/style_emoticons/default/smile.gif

 

Reminds me, I need to leave feedback.

Edited July 15, 2010 by Edde

[ucw458]

Guys there really is no retrofitting nescesary for converting to 134a. Just fix the leak, pull a vacuum and recharge with 134a. Yes the oils are different but they still mix ok. I could go into detail about how they are different but lets keep it simple. Add about 4oz of 134a oil when you recharge and you will be fine.

 

I am an HVAC tech by trade and I have NEVER done any conversion to 134a on any vehicle. I simply fix the leak and add 134a with a little oil. I have NEVER had a problem with my AC from doing that. Even my 67 ford was done that way 10 years ago and the AC still works. The whole deal behind needing a retrofit was started by the EPA because they don't want refridgerant leaking out. Doing a "conversion" assures that all the seals are leak free.

 

 

I'll give you a big hint as to where the leak probably is. The large vapor hose leading from the firewall to the compressor probably leaks. Every one of my SQs leaked there. $50 to have a new hose made and problem solved.

[Edde]

Guys there really is no retrofitting nescesary for converting to 134a. Just fix the leak, pull a vacuum and recharge with 134a. Yes the oils are different but they still mix ok. I could go into detail about how they are different but lets keep it simple. Add about 4oz of 134a oil when you recharge and you will be fine.

 

I am an HVAC tech by trade and I have NEVER done any conversion to 134a on any vehicle. I simply fix the leak and add 134a with a little oil. I have NEVER had a problem with my AC from doing that. Even my 67 ford was done that way 10 years ago and the AC still works. The whole deal behind needing a retrofit was started by the EPA because they don't want refridgerant leaking out. Doing a "conversion" assures that all the seals are leak free.

 

 

I'll give you a big hint as to where the leak probably is. The large vapor hose leading from the firewall to the compressor probably leaks. Every one of my SQs leaked there. $50 to have a new hose made and problem solved.

 

 

Good info. Question for you: What would cause the compressor to not work until the car goes into closed loop?

[ucw458]

Good info. Question for you: What would cause the compressor to not work until the car goes into closed loop?

 

 

You got me on that one. IDK.

 

 

wait, I may have an explination. First some background info. Is your car an 86-87? Non Auto trans? If so you may have the AC switch hooked up wrong. My 87 has 4 connectors in the temp sender area. One is for the temp sensor (ecu) Then 2 single wire connectors, one for the AC switch and one for the temp sender (gauge) and finally another 2 prong connection for an auto trans temp sender.

 

The T stat housing holds the AC overtemp switch. Below that is the temp sender. If you have a 2 prong sender one side is for the gauge and the other is a switch to not let an auto trans go into OD until the engine is warmed up. Any chance you have the AC switch wire connected to a 2 prong temp sender?

[Edde]

Positive that stuff is correct. It's an 87 w/88 ecu. I didn't fully charge it yet - hate to bust a second can. Don't know. I got what looks like a generic temp switch from rockauto cause it was only part # I could find. Could be that I guess.

[Autox77]

Hello, I am trying the conversion also but my mechanic cannot find the fittings of the correct size..he found the low side but not the high side...could anyone tell me the part number or how to identify the correct pieces at NAPA or Auto Zone? Thanks

[Coke]

This is very good information. It should be stickied.

[tsi_tom]

I need to do this so bad. It is very hot in Pennsylvania now. Jeff you did replace all the o-ring seals?

 

Edited July 31, 2015 by tsi_tom

[Sharpshifter]

The main argument for converting from R-12 to R-134a is the compatibility of oils. An R-12 charge requires mineral oil, while R-134a requires ester oil.

 

I have been running a R-134a synthetic in my stock A/C system with no problems, courtesy of the 'adapter' fittings available at most auto supplies. Freeze-12 or other synthetic R-12 replacements would come much more highly recommended and offer a much more suitable(read: compatible) alternative to R-12. Seriously, this stuff is under $10 per can. Don't waste your money on an expensive full 134a conversion which requires swapping out of your condenser to a 'high efficiency' type.

 

High efficiency? Oh because of the low efficiency gas. Right.

 

Again, having said that, the R-134a has been fine in my system. Incompatibility with the oils supposedly creates issues with the old seals, but the jury's still out on that, in my opinion.

Edited August 3, 2015 by Sharpshifter

[ucw458]

Again, having said that, the R-134a has been fine in my system. Incompatibility with the oils supposedly creates issues with the old seals, but the jury's still out on that, in my opinion.

 

 

The problem behind that is the oil must be miscible with the refrigerant. Meaning it must mix with the refrigerant to be carried throughout the system. If it can't mix then all the oil could end up in the condenser or evaporator. When that happens the AC stops working and the compressor can burn out. Ester oil and mineral oil will mix somewhat with each other but r134a wont mix with mineral oil and r12 wont mix with ester oil.

 

What I do is on a known good system I fix any leaks then add a 2 oz ester oil charge then r134a. If it's a new compressor on a system that's been pieced together I use an 8 oz ester oil charge. Any residual mineral oil in the system will get pushed around by the ester oil charge.

 

 

 

You don't need to change filter/driers in the system either. They are not like oil/air filters. All they contain is a small metal screen, a piece of fiberglass and some desiccant. Desiccant is small balls of material that absorb some water vapor. Proper vacuuming of a system before charging removes the water vapor. It can also remove the water vapor the desiccant has absorbed if under vacuum long enough. So there's no need to replace the filter/drier.

 

 

SQs may not have it but lots of newer cars have a fine screen like filter on the high pressure hose connection at the firewall. That screen prevents debris from getting into the TXV and damaging it. I have seen those filters get plugged up. Especially when a system was pieced together. Clean or replace those filters as needed.

[Sharpshifter]

Good information to know. I'll wager a good amount of my success is the residual R-12 charge that was in the system before I topped it off.

 

It blows icicles on the highway... but warms up a bit when stopped at a light. I'm not complaining, but I have plans to flush it all out and charge it with the R-12 replacement. I did this on my old 68 Jeep and it's like a meat locker.