Changing A/c System...help Needed!

[1991LS400]

Hey guys,

I have a 1991 Lexus LS 400...

As we all know R-12 is starting to become harder and harder to find and mechanic shops in most areas of the U.S. don't have the systems needed to recharge or refill freon into an R-12 system and, of course, they do not have the R-12 freon since all cars now have the R-134a system.

I purchased a complete recharge and retrofit kit to change my R-12 A/C system to a R-134a A/C system and I have a friend who is going to help me out tomorrow morning. I already got all the R-12 freon out of my system through that tube on the top left-hand side of the engine bay (the one with the black cap, you 1st Gen DIY guys know what I'm talking about) and tomorrow morning we are going to recharge and refill it with the R-134a system.

However, before I go through with this, is it ok to do this? My A/C doesn't blow cold air anymore anyway (even though my climate control says it's blowing 65 degrees farenheit) and since I know even if it doesn't work it's not like it will harm my engine since the A/C system is totally seperate. I do not want to keep looking for R-12 so I need to switch to the R-134a.

Please, if you guys have any advice before I do this, let me know. And even if you think it will be ok let me know that as well! Optimistic outlook will be greatly appreciated!

P.S. I paid $50 for this kit so if you guys think I should refund it tell me! $50 is a lot of money to me. Even if I spend a penny, I'm a penny poorer, and vice versa.

[obergc]

I have been told that the oil used with the R12 freon is not compatible with the synthetic oil used in the R134 systems. The old oil should be flushed out of the system before putting in the R134 and you should then install synthetic oil with the R134. . Also, the o-rings used in the R134 system are different from the o-rings used in the older systems. I think you will eventually be disappointed in the results if you simply bleed out the R12 and replace with the R134. Good luck in your conversion.

[maxed_out]

Hey good luck. I did mine a couple years ago and it needed to be flushed too. I had to put in new oil compatible with 134a,new o rings, and a different drier (also compatible with 134a) . I read about the procedure online for a few days before and If I had the link I would have posted it for yah. You might want to try a search for the specific procedure before jumping.

I also took the compressor out and had an a/c shop go over it. They fixed a leak by rebuilding it. Found the leak because of all the oil drooling off compressor.

All turned out well...I'm no a/c pro but I'm pretty happy with the results...been a couple years and no problems and if I need a can I can of juice I can find one pretty easily.

I've since heard stories about folks doing a lot less than I went through and they swear by there results.

I also learned on this forum that you can get r12 on ebay. I had no idea.

Let us know how it goes!

[914lps]

There are other post on this. What you are doing is WRONG. You just dumped your r-12 into the air for no reason! Other then to screw up the planet!... If you want the recharge to work you will need to have a shop vacum down the system. If you had some old r-12 left in the system ou may have found someone to do it for free as they can sell the r-12 they pull out.

Also do not replace r12 with 134a in the same amount. About 80% of a charge with 134a works as good as a full charge if r12. If you do a "full" charge of 134a the system will act like it is over charged and not cool as well.

Your not a nice person, so I'm not going to tell you the other stuff you need to know. Hay, when you do your oil changes do you put the old oil in the storm drain!

[1991LS400]

There are other post on this.  What you are doing is WRONG.  You just dumped your r-12 into the air for no reason! Other then to screw up the planet!... If you want the recharge to work you will need to have a shop vacum down the system.  If you had some old r-12 left in the system ou may have found someone to do it for free as they can sell the r-12 they pull out.

Also do not replace r12 with 134a in the same amount.  About 80% of a charge with 134a works as good as a full charge if r12.  If you do a "full" charge of 134a the system will act like it is over charged and not cool as well.

Your not a nice person, so I'm not going to tell you the other stuff you need to know.  Hay, when you do your oil changes do you put the old oil in the storm drain!

←

For your information I did have the R-12 sucked out by a mechanic today. He had some sort of machine that caught and sucked out all the R-12. Calm down.

Well, some people say I can change it to R-134a and some say there's a lot more things I gotta do which I don't have the money for right now. Now that I have no freon on my system should I just return the R-134a upgrade kit that I got and get some R-12 freon on E-Bay and a charging hose? Wouldn't I need a pressure gauge so I know how much to put back into my system? All the freon is out of my A/C system now. Texas is too hot without an A/C! PLEASE HELP!

[1991LS400]

Well I just looked on E-Bay and for every single auction for R-12 I need to have an EPA certifcation before I can purchase the R-12 freon. I do not have this certification, I do not have anymore R-12 freon in my A/C system, and I still have the R-134a complete recharge and retrofit kit. What do I do now? I can't waste anymore money on things that won't work. Advice desperately needed!

[larryp]

Brian,

If you can't find a local shop to recharge w/ R12 here's my recommendations:

1. Have the system vacuumed to remove all the R12. Sounds like you've done that.

2. Flush the system completely to remove ALL the R12 oil.

3. Purchase a new receiver dryer from ACPARTSNOW.COM for $16.83 plus shipping

4. Install new dryer

5. Add PAG46 compressor oil

5. Pull vacuum on system to remove all moisture and then recharge with R134a (using your retrofit kit).

You didn't mention why the system stopped working. You don't want to go through all this and then find out you have a leak.

Good luck.

[1991LS400]

Brian,

If you can't find a local shop to recharge w/ R12 here's my recommendations:

1. Have the system vacuumed to remove all the R12. Sounds like you've done that.

2. Flush the system completely to remove ALL the R12 oil.

3. Purchase a new receiver dryer from ACPARTSNOW.COM for $16.83 plus shipping

4. Install new dryer

5. Add PAG46 compressor oil

5. Pull vacuum on system to remove all moisture and then recharge with R134a (using your retrofit kit).

You didn't mention why the system stopped working. You don't want to go through all this and then find out you have a leak.

Good luck.

←

larryp,

I feel that I may have a small leak somewhere in my A/C system (don't know if it's a line or what) because when I purchased the vehicle last May (it has been exactly a year) the A/C was working fine all the way until last month (April). If I have a leak I feel it may be a really small and slow leak. I don't know how to go about finding the leak without paying a crap load of money at some mechanic shop. And the price on the dryer is pretty good but how much to install it? Can I do it myself? And where do I get PAG46 compressor oil? And do most shops have the machines to remove the R12 oil? I need a little more detailed steps in what I should do.

Thanks all.

[larryp]

larryp,

I feel that I may have a small leak somewhere in my A/C system (don't know if it's a line or what) because when I purchased the vehicle last May (it has been exactly a year) the A/C was working fine all the way until last month (April). If I have a leak I feel it may be a really small and slow leak. I don't know how to go about finding the leak without paying a crap load of money at some mechanic shop. And the price on the dryer is pretty good but how much to install it? Can I do it myself? And where do I get PAG46 compressor oil? And do most shops have the machines to remove the R12 oil? I need a little more detailed steps in what I should do.

Thanks all.

←

Brian,

The receiver/drier is super easy to install. It's behind the right headlight.

You can buy ac flush product to remove the oil but you really need equipment to do the proper flush otherwise you can't get the flush to move through the system. A shop specializing in AC repair should be able to handle. I replaced my compressor (locked up) and dryer and blew out the rest of the system with compressed air.

I also replaced all o-rings in the entire system because they say the existing o-rings are not compatible with r-134a. Over time they may deteriorate. Replacing the o-rings is not a big deal except for the evaporator which is inside the blower unit. The blower unit is behind the passenger side dash and is a bear to get out. There are only 2 o-rings to replace in here so if i had to do it again i'd take my chances on those 2 and just replace the rest.

The compressor oil is available at any auto parts store. Should take 8 oz. Remove suction side tube from compressor (labeled "S") and pour oil into compressor.

You can buy flourescent dye (for r134 systems) and a detection kit (got mine at Autozone for $12). I had a leak after doing the repairs but the dye didn't show any leaks (or at least i couldn't find them). That's when i replaced all the o-rings and found one that was damaged.

Now i'm riding cool just in time for those days where the heat index in Mississippi goes over 100.

Hope that helps.

Larry

[maxed_out]

Hey how did this turn out????

[JPI]

Brian,

If you can't find a local shop to recharge w/ R12 here's my recommendations:

1. Have the system vacuumed to remove all the R12. Sounds like you've done that.

2. Flush the system completely to remove ALL the R12 oil.

3. Purchase a new receiver dryer from ACPARTSNOW.COM for $16.83 plus shipping

4. Install new dryer

5. Add PAG46 compressor oil

5. Pull vacuum on system to remove all moisture and then recharge with R134a (using your retrofit kit).

You didn't mention why the system stopped working. You don't want to go through all this and then find out you have a leak.

Good luck.

←

larryp,

I feel that I may have a small leak somewhere in my A/C system (don't know if it's a line or what) because when I purchased the vehicle last May (it has been exactly a year) the A/C was working fine all the way until last month (April). If I have a leak I feel it may be a really small and slow leak. I don't know how to go about finding the leak without paying a crap load of money at some mechanic shop. And the price on the dryer is pretty good but how much to install it? Can I do it myself? And where do I get PAG46 compressor oil? And do most shops have the machines to remove the R12 oil? I need a little more detailed steps in what I should do.

Thanks all.

←

Hey Brian,

I would advise you to find the leak and then convert it over to r134a. Here are the common problems on the Ls400: leaky compressor(front seal), leaky high pressure hose(this hose coming off the compressor) and leaky evaporator core. Apply 1 pound of freeze 12 into the system and the the dye. Get black light and find your leak. Once the leak is located, go ahead and replace the unit. Flush all the lines and replace all the 0-rings. Don't forget to add some oil, change out the fittings, vaccum the sytem. Close both manifold gauge to see if the pressure do hold. Apply the right amount of r-134a and you are good to go. I do miss a couple of items but feel free to email me. Have a cool summer because it's hot in Dallas :( .

JP Importz

[VGR]

Six points 1991LS400:

1. For 10 years there has been lots of R12 available on ebay and the price has been going DOWN in recent years because the supply EXCEEDS the demand. ANYONE can buy R12 and the charging hose on ebay, by simply supplying the seller with a letter stating you intend to resell it or give it to a licensed person to install. No one in government or law enforcement is actually going to track what you do with your cans of R12 after the sale. So in reality, nearly all of the tens of thousands of people who have purchased R12 on ebay over the past 10 years are ordinary do-it-yourselfers like you and me.

2. A week ago your system probably merely needed to be topped off with a can or so of R12. However, since you recently hired a mechanic to get rid of the existing R12 in your system your system is now depressurized, allowing some atmospheric moisture to enter and contaminate your system. So now recharging is going to be a more complicated and expensive affair because instead of simply hooking up a charging hose, the system must first be vacuumed for 30 minutes using a vacuum pump (to remove system moisture) and then 3 cans of R12 charged into the vacuum. And only AC shops have this vacuum pump.

3. Few auto shops will recommend sticking with R12 because they make much more money on R134a conversions and all the system modifications needed to convert (like new barrier hoses, a new receiver drier and special R134a compatible 0-ring seals, the flushing chemical, etc).

4. Unlike nuclear waste, R12 is not going to stored for centuries deep inside Yucca Mountain Nevada. All R12 is going to end up in the atmosphere one way or the other so one should not feel guilty venting small amounts of it to the atmosphere, especially considering it's still legal for millions of people in 3rd world countries to buy and vent R12 to the atmosphere.

5. 1991LS400, if money to repair your slow R12 leak is tight right now, then just get the system vacuumed and recharged with 3 cans of R12. Then if the system ever gets low on R12 again, buy a can of R12 on ebay together with the charging hose and top the system off yourself. Just don't ever allow ithe system to become totally discharged again or else you will have to go through the vacuum pump routine again.

6. If you decide you can't resist the unrelenting peer pressure and auto repair industry pressure to "upgrade" to R134a, beware you will permanently lose the ability to monitor system charge using the sight glass built into your system.