AC - Converting 90Q to R-134

[DrewQ45]

Looks like I'm the only one talking AC right now... but sooner than later, it's going to be a hot topic... pun intended. I'm going to let my other post die since it's being ignored...lol

Well,

I've finally decided on it. R12 is a hassle and I can't even find the right oil for Freeze12 without a license. On my last visit to Advance Auto, they lectured me against using it because of the high butane content... so screw it... R-134 it is. I don't care if it's a few degrees warmer.

I think I'll use the Interdynamic conversion kit. Check out their diy video here... http://www.id-usa.com/video/re...h.wmv

Here's a question I will pose to Interdynamic tomorrow... If anyone knows the answer, please chime in. The kit I saw at Advance had three cans of freon each containing 2 oz of compressor oil mixed in. They are emphatic that no more than 3 cans are to be used to charge a car's system. That makes it a max of 6oz of oil in the system... the Q requires 8oz total. They also instruct to have the compressor running for three minutes before adding freon.... That's a totally dry compressor!!! Since the system is pulled apart, I will add ester oil to it manually and recharge with gas only (no oil mixed in). See question below....

"It’s stated that the system must be charged with freon to 80% it’s normal capacity because R134 operates at a higher pressure than R12. I will be adding ester oil to the compressor from a bottle since I am having the system flushed and it’s currently pulled apart. I guess I will need a recharger kit with no oil mixed into the Freon. Will I be adding the normal amount of oil (8oz.) to the system, or does the 80% rule apply to the oil also?"

Chime in if you know the answer...

[Q45tech]

The R12 flex hose will gave to be replaced with R134a type hoses.

After the flush an ac machne will be necessary to vacuum down to micron torr minimums then the machine adds the necessary oil prior to adding freon.

You can get certified by passing the on line test and sending money [$15]

http://www.macsw.org/certification.php

[maxnix]

Read Q45tech's posts.

Basically, you have to change out everything if you want it to work right.

If you can live with 80% effiecency, there is less to do.

But DIY AC work with R12 in particular is a ferderal offense.

[DrewQ45]

http://www.id-usa.com/how_to_f...sp#10

7. Can I mix R-134a with a little remaining R12 in my system?

No, the system must be evacuated first down to a vacuum measured at approx 29 inches of water.

10. Do I have to change A/C system components to retrofit?

In the beginning, when retrofitting vehicle air conditioning systems first came up, it was assumed that major components of the system designed for use with R-12 would have to be changed to R-134a compatible components. As more research was done, and as vehicles were actually retrofitted, the industry learned more and more about the process, namely that much less had to be done than was originally thought.

If an R-12 system is functioning properly, components do not have to be changed, and the R-12 refrigerant can be replaced with R-134a without opening up the system. If, however, the system is not functioning and repairs must be made, then the defective parts should be replaced with R-134a compatible parts.

R-134a is a smaller molecule than R-12, so R-134a hoses are designed to contain it properly. In an R-12 system, the original hoses and O-rings absorbed some of the mineral oil in the system and are coated internally with mineral oil forming a protective barrier. So, if they are not damaged, R-12 hoses and O-rings do not need to be replaced.

[Q45tech]

R12 is not a hassle easiest of all to deal with.

Conversion are the hassle [to get to function correctly].................we see them every day..................half axxed conversions that don't function right and owners wanting us to fix them.

In Summer I see so many old Q in interstate and city traffic with windows down.

[maxnix]

If you read Dennis' original posts or caompare part numbers between an R134a and R12 system, you will see there are many differences in the condenser, condenser fan, expansion valve, etc. Conversion is a myth. Replacement of the whole system is what is required.

One other thought. The grille of the later cars is rumored to be necessary to allow the less efficient R134a extra cooling to match earlier R12 configurations.

The original posts are a gold mine of in depth discussion often not repeated. (fatigue does set in, memories fade, etc.).

[DrewQ45]

If you read Dennis' original posts or caompare part numbers between an R134a and R12 system, you will see there are many differences in the condenser, condenser fan, expansion valve, etc. Conversion is a myth. Replacement of the whole system is what is required.

One other thought. The grille of the later cars is rumored to be necessary to allow the less efficient R134a extra cooling to match earlier R12 configurations.

The original posts are a gold mine of in depth discussion often not repeated. (fatigue does set in, memories fade, etc.).

I appreciate the info Maxnix, but I have reasearched this thing to death and it would seem that replacement of the whole system is not necessary.

True, when R134 was first introduced, this was thought to be the case. There is now a wealth of objective information on the web/here on NICO with people who ignored the warnings because they didn't care or had nothing to lose (crappy old cars). Years later, their systems are still cooling fine. As long as the system was working well with R12 to begin with, the drier changed, system properly flushed and the correct oil added, it should work. I'm definately not blazing any trails here. I'll let you know how it turns out for me.

[Jesda]

Freeze can be found on eBay for cheap. No license needed.

In my case, I picked it up at a local parts store. Some Advance Auto Parts and AutoZone stores have it if you call and ask.

[DrewQ45]

And the saga continues... I had AC system chemically flushed today. They use a fast drying solution to flush the lines and the condenser. The guy that performed the flush said he didn't see any gunk or contaminants expelled. My condenser had a little back-pressure for a moment but it cleared fast. He only charged me forty bucks for the flush because I brought the car to him with the lines all pulled.

Nothing like sucking the knowledge from a professional who has been doing AC work since the sixties... He and the internet schooled me a little.

The evaporator is not flushed due to it being on the low pressure side of things and being behind the expansion valve. The evaporator can hold as much as 3ozs of leftover oil. Technically, it could be flushed but is not absolutely necessary and not advisable due to the work involved. R12 and R134 oil won't mix but can coexist as long as R134 oil is 80% or greater in the system. Hoses don't need to be changed as long as in good condition and flushed clean.

When adding R134 freon, add 20% less than one would with R12. The former expands more = higher pressure.

G50 holds 44oz of R12 = 35.2 oz of R134.G50 = 8oz of oil.

Too much oil and the system won't cool properly. Too little and your compressor self destructs.

If adding oil to compressor yourself, chose initial refrigerant carefully as most DIY refrigerant kits have 2% oil already added. Buy pure freon mixed with no oil in this case. When recharging low system however, it's okay to use refrigerant laced with oil as the expelled refrigerant took oil with it.

Compressor must be removed from car and all old oil drained out via the drain plug on the side. Add new oil to compressor's suction port (it's actually labelled "suc" I think) while turning compressor by hand to distribute within. Turn 16-20 times each direction while slowly adding lubricant. Use Ester oil versus PAG as it's less hygroscopic (water absorbency). I used Castrol synthetic ester with UV dye. With UV added you can use UV glasses to spot leaks...the leaks would glow.

Use new drier but do not connect lines or open rubber plugs on new drier until just prior to vacuuming system. The drier contains a dessicant which absorbs water from air and should not be exposed to air for long less it become useless.

...I'll add more info as it comes to me.... After all this... I hope my AC cools.... LOL. I'd like to see more owners convert their AC over themselves.

Please please view the video earlier on in this thread if you decide to try this.
Modified by DrewQ45 at 9:51 PM 3/20/2007

[stock1992q45]

I'm trying to decide what to do for my 92Q.

2 options I'm consdiering:

1) buy the OEM kit for R12. $600 part + $150 freon + labor

2) a local a/c mechanic suggested an aftermarket R134 converison kit which he'll warrant for one year. He says R12 won;t be available in a year. I don't beleive him. $900 total

My original a/ went 13+ years, 200,000+ miles before needing charging.

That's why I'm drawn to the R12. I plan on keepin the car for another 5 years, 50,000 miles.

Any comments? Warning?

Thanks

[ScottJackson]

How about using R290 (propane)? Being a farmer sort, I know guys use it in their tractor A/C. Yeah, it's somewhat flamable, but not really explosively dangerous. And it's cheap. Would it work fine in a Q a/c system?

[statichead2k]

I swapped mine 93 over to r-134 at the end of Jan, yeah in AZ that was when I first wanted the air.

Any way. I was told it used ester oil so I changed the dryer ($60) added the port conversion ($30), ran a vacuum on it over night with an el-cheapo from harbor freight vacuum pump(29.99 or less), and filled it with 134A and a little oil ($30 +/-).

It has been cooling like a champ since.

Two things; my system was pretty much empty when I started (leaking around the dryer seals) and don't over think A/C. It is simple vapor phase, not rocket science. Even in a Q.

If it still seeps a little? Well R-134 is cheap and can be bought over the counter.

Now back to my Margarita.

[statichead2k]

I swapped mine 93 over to r-134 at the end of Jan, yeah in AZ that was when I first wanted the air.

Any way. I was told it used ester oil so I changed the dryer ($60) added the port conversion ($30), ran a vacuum on it over night with an el-cheapo from harbor freight vacuum pump, and filled it with 134A and a little ($30 +/-).

It has been cooling like a champ since.

Two things; my system was pretty much empty when I started (leaking around the dryer seals) and don't over think A/C. It is simple vapor phase, not rocket science. Even in a Q.

If it still seeps a little? Well R-134 is cheap and can be bought over the counter.

Now back to my Margarita.

[DrewQ45]

I'm trying to decide what to do for my 92Q.

2 options I'm consdiering:

1) buy the OEM kit for R12. $600 part + $150 freon + labor

2) a local a/c mechanic suggested an aftermarket R134 converison kit which he'll warrant for one year. He says R12 won;t be available in a year. I don't beleive him. $900 total

My original a/ went 13+ years, 200,000+ miles before needing charging.

That's why I'm drawn to the R12. I plan on keepin the car for another 5 years, 50,000 miles.

Any comments? Warning?

Thanks

Just do what I'm doing.

Dryer (shipped) roughly = $70.00 (can't quite recall)Assorted O-ring pack = $4.00Bottle of ester oil and three 12oz. cans of R134 = $40AC System flush = $40

I might spend roughly $100 more when I get the hose/gauge and fittings +vacuum. I'll charge it myself.

Total = $254.

Future Freon will be cheaper than R12 and the conversion helps resale value a bit. I don't have to worry about the atmosphere and flammability is much lower than Freeze 12 (high butane content). Not dangerous for you as long as there is no leak. You be the judge.

[DrewQ45]

Well it's finally done! Cost me less than I thought to finish. Had a shop vacuum it down and charge (with the freon I provided) for $40 last night. It's cooling nice... not ice cold like R12 but seems like it should be cool enough. I'll find out today as it will be about 80 degrees in ATL.

The nice thing is that If I'm not satisfied with R134, all I have to do is evacuate the R134 and add Freeze12. No need to change the oil since ester works both ways!

Not everything went as smoothly as planned. I somehow managed a RyanH and broke the long tensioner bolt on the compressor pulley. Had to push up hard on the pulley and lock it with the lock-nut but the belt is still loose... Back to the junkyard this evening. Also, the R134 fitting that I screwed on the low pressure side started to leak/spew soon as the charging hose was removed. I hurriedly removed it for now.

...Drew...

[DrewQ45]

Sometimes I think the devil is out to get me.

As I was saying, I did a RyanH and broke the tensioner bolt for the AC compressor pulley. I’m not sure why it broke because the belt wasn’t even tense yet but there was great resistance loosening and tightening even after spraying it with WD-40. It almost seems as if it was cross-threaded, but it wasn’t. It snapped just about an inch from the head. I managed to pick up two bolts from the junkyard but what a bit*h to get the broken bolt out!!! Damn thing was possessed! To remove just the head, I had to dent the engine oil pan to gain clearance. Let me tell you, Nissan badly designed the bracket on which this tensioner glides. For one, it’s made of very lightweight and extremely brittle aluminum which cracks/breaks easily. Secondly, it’s one large unit…which also houses the compressor and the alternator. I know they were trying to keep things light but this bracket should have been made of iron considering all it does. I would have been in a world of hurt had it broken all the way… it cracked at the very top of the diagonal slot on which the tensioner slides, but not in a place where I had to replace it. Wondering if can get it welded?

To get the rest of the bolt out, I was using my channel-lock pliers to grip the shaft and it took almost super-human effort to get even a quarter turn out of it. I was gripping it so hard it broke three more times and I only had like a quarter inch left to grip on it before it finally came out. I only succeeded because I got smart and took back both my Craftsman channel-locks to Sears and exchanged for new. Fresh teeth made a big difference in the grip. I also picked up one of those “Robogrip” pliers and it didn’t help at all - made in China POS! I’m taking it back.

If anyone ever broke this bolt you’d know what I’m talking about. Glad no kids were around as my language degenerated badly!

Anyway, with the belt fully tightened my AC is cooling like a champ now with R134a freon. Conversion is no myth!!!

….Drew…

[maxnix]

Conversion is no myth!!!

Ah yes, but without data the performance is. Of course, you will have to wait for summer and some real thermal loads. It is now only 3 days into spring.

Read Q45tech's posts about idle in summer conditions and temperature drop across the coils per unit time.

At least you didn't use an explosicve gas!

[DrewQ45]

Ah yes, but without data the performance is. Of course, you will have to wait for summer and some real thermal loads. It is now only 3 days into spring.

Read Q45tech's posts about idle in summer conditions and temperature drop across the coils per unit time.

At least you didn't use an explosicve gas!

Atlanta was 80+ degrees yesterday and the car sat in the hot sun all day with windows fully closed. It cooled quickly and on the drive home, I found myself raising the temp because I was getting too cold. Granted, it's not R12 and someone who keeps the temp set at 70, may need to have it set to 68 for the same level of cool but who cares? I'm happy and that's all the proof I need brotha. I suppose I could spend a few bucks and buy a vent thermometer to prove it but why spend more than the roughly $200+ change that this conversion cost me?

Be careful what you deem a myth without actually having tried it. There are members here who might actually believe you. I spent the time, money and effort to research this and actually do it the right way and it should last for years to come.

...Drew...

[maxnix]

Yeah, and the conversion kit form Infiniti was a myth also?

Catch up with Dennis and when he does his instrumented AC test in the summer, he might let you borrow the equipment. It would be interesting and useful to compare a properly functioning R12 system vs. a R12 system with R134a. Nothing like data.

[kdkrone]

Doug, (or anyone else)

When you have a sec, I would be grateful if you could help me understand the issue with the air conditioning; I have a 92 with 114K miles and the AC is not an issue yet, but I would like to be informed in case the issue arises. I would appreciate someone filling in the gaps...

Apparently, the R12 is a compound that the gov't doesn't want around contaminating the planet so there has been a mass conversion of units that fail or need a refill. The price of the R12 is now $75 or so a pound, which is pretty expensive.

I do not understand what R134 is or when it is used, but I assume it is a compound that replaces R12 and is environmentally acceptable? Is that compound used in the original AC unit? If so, there is some conversion kit that needed, and, if so, at what price?

Now, is there also a replacement AC kit for the original one that uses a newer compound (R-134? another one?) The cost?

What else do I need to know?

ThanksKen K

[Jesda]

I had poor performance with R134. I guess its one of those YMMV things.

I'm scheduling an appointment with the dealer to flush/refill the R12 and replace the receiver.

[Q45tech]

Most people don't realize that AC systems fail progressively as the dirt builds up on evap/condenser and as an amount of R12/R134a leaks our thru orings and hoses each year.

The AC computer and compressor automatically adjusts its fan speed, blend doors, and displacement volume to maintain the exact set temperature.................so for the first few years of use nothing is apparent.

The astute ones might note the fan speed has risen or it begins to take longer and longer and longer to cool down.

Compressors wear seals and get noiser each year and the high pressure drops.

Finally it quits entirely....................then people complain.

The system is optimized for one particular gas type and will not function properly with a substitute. It will cool somewhat just below standards.

Failure to periodically replace the lube oil allows it to react with moisture and turn acidic and eat holes in the aluminum components.........this often takes 7-12 years and usually the compressor fails in that time frame so the system gets flushed.

Low cost cheapy repairs with just a 12 month warranty are never designed to return the system to brand new which would cost thousands [$2500] in parts alone...................so periodic new failures result after changing the first compressor or evap or a recharge in gas.

[RyanH]

As I was saying, I did a RyanH and broke the tensioner bolt for the AC compressor pulley.

If everyone could keep this kind of reference up, I'll soon be famous!

[maxnix]

If so, there is some conversion kit that needed, and, if so, at what price?

Now, is there also a replacement AC kit for the original one that uses a newer compound (R-134? another one?) The cost?

There was an OEM conversion kit at one time, and it included new evaporator, new condenser, and I think a different compressor. Due to all the labor (not to mention the parts cost), they probably only sold less than ten of them. Remember, true or not, the 1994+ grill was alledgedly installed to get more air to the coils so the less efficient R134a worked better.

There is a lot of detail in Q45tech's early posts. Ignore them at your car's peril!

Thus, is is generally better to maintain an R12 system by mechanically replacing the lubricating fluid, R12 and dryer periodically for a couple of hundred than spending thousands to convert to R134a. Q45tech has posted several times on this topic and how this is properly accomplished.

While the release of any hydro-carbon-flouride gas is not good, and thus illegal, the effects of R12 vs. R134a are not totally understood on the long term. Nevertheless, running a combustible gas as a substitution for either will hopefully be avoided by our members for obvious reasons.


Modified by maxnix at 9:12 AM 3/25/2007

[DrewQ45]

If everyone could keep this kind of reference up, I'll soon be famous!

Ryan my man, you already are!!!

[DrewQ45]

There was an OEM conversion kit at one time, and it included new evaporator, new condenser, and I think a different compressor. Due to all the labor (not to mention the parts cost), they probably only sold less than ten of them. Remember, true or not, the 1994+ grill was alledgedly installed to get more air to the coils so the less efficient R134a worked better.

There is a lot of detail in Q45tech's early posts. Ignore them at your car's peril!

Thus, is is generally better to maintain an R12 system by mechanically replacing the lubricating fluid, R12 and dyer periodically for a couple of hundred than spending thousands to convert to R134a. Q45tech has posted several times on this topic and how this is properly accomplished.

While the release of any flouride gas is not good, and thus illegal, the effects of R12 vs. R134a are not totally understood on the long term. Nevertheless, running a combustible gas as a substitution for either will hopefully be avoided by our members for obvious reasons.

Yawn....

Do some research other than searching under "Q45tech".... Understand that at $200, I really don't care if it only last for 5 years. I will still be making out like a bandit. Any futher work I do will be less the cost of an evaporator and flush so that cuts the $ number more than half.

R12 is a hassle and that hassle increases exponentially as years pass. I actually started out trying to convert to Freeze12 which is the most available R12 substitute. Heard stories of smokers igniting while running AC from which R12 was leaking from evaporator directly in the cabin or while performing DIY. Safest and most legal gas to work with DIY = R134 . You can vent it into the air if you want which would land you in the clinker with R12!

Doing a little research will show that it's suggested to stick with R12 if your system is working fine, however, if doing major work such as compressor replacement, after which you should flush + replace drier anyway, thats the time to consider converting. I'm not knocking R12, just making things a lot ea$ier from here on. Had the conversion not satisfied me, you can bet I'd be going back with the quickness.

Point blank, the car cools and cools more than adequately. The system was flushed, new drier installed and Castrol synthetic compressor oil with UV dye added. The compressor was used, but a recent remanned which runs very quietly and had clean yellow oil flowing out of it when I opened it. It will last for years.

Remember that I'm driving a 210K car. Do the logic.

You can keep contributing to global warming (AC-wise) if you want. A cruel twist to all this is that the more you use R12, the more you will need it!
Modified by DrewQ45 at 11:57 AM 3/25/2007

[maxnix]

Safest and most legal gas to work with DIY = R134 . You can vent it into the air if you want which would land you in the clinker with R12!

Most definitely not true, and anyone who passed 8th grade genreal science should know that venting flourohydrocarbons is not a good idea.

"In fact, it is illegal to vent any type of refrigerant from a vehicle, including R-12, R-134a or any other alternative or unknown refrigerant. The prohibition against venting includes even a small charge of refrigerant that may have been added to a vehicle for purposes of detecting a leak. If there is any refrigerant in the system at all, it must be recovered and not allowed to escape. Period."

http://www.aa1car.com/library/2003/ts30324.htm

[DrewQ45]

Most definitely not true, and anyone who passed 8th grade genreal science should know that venting flourohydrocarbons is not a good idea.

"In fact, it is illegal to vent any type of refrigerant from a vehicle, including R-12, R-134a or any other alternative or unknown refrigerant. The prohibition against venting includes even a small charge of refrigerant that may have been added to a vehicle for purposes of detecting a leak. If there is any refrigerant in the system at all, it must be recovered and not allowed to escape. Period."

http://www.aa1car.com/library/2003/ts30324.htm

Well you got me there, but it's much less damaging to the ozone than R12...When mentioning eight grade, at least spell "general" right.

Here's something that might interest you.... had the car sitting in the driveway all morning. It's 84 degrees in ATL (go check CNN) so it was a furnace when I got in. Took a ride to the store and back. Along for the ride was my Brookstone house clock which has a temp sensor on the front . It's the best I could do since I won't spend money to prove it to you. The ambient temp is being displayed on the HVAC display.

Can you see the myth hard at work? Hopefully this will put an end to our discussion . Either way, I'm done and will enjoy the summer riding in the cool...

Oh, one more thing.... a shameless plug for the products I'm selling in the parts forum. Pics below the myth. Half price for you Maxnix....NOT!

...Drew...

[maxnix]

Vent temperature at 95° F ambient should be ~43° F.

Predicting a sweaty summer in that car, but better than nothing. But not as good as R12 in an R12 system.

"Member's standards vary." - Q45tech.

[DrewQ45]

That wasn't vent temp my friend. That big thing I'm holding is no vent thermometer. Also, I hadn't even turned on recirc (forgot).

Atlanta averages 86-89F degree temps in the summer so we are close to average already.

Case closed. I think we have beaten this thing to death.

...Drew..