A/C Questions before I do what I'm going to do anyway

Fastback86 · Post by **Fastback86** » Wed Apr 30, 2008 6:44 pm

Here's the skinny:

3 years ago when I sent my sad little 2.8 off to the big recycling center in the sky, all of the R12 from my A/C system decided it couldn't go on living without the 2.8 and went with it. It was tragic. Since then, I've been making due with no A/C, but now that I live in San Jose and will likely be moving to LA, I want my conditioned air back.

About 2 years ago, I bought a R134a conversion/recharge kit and charged it back up. The next day, I actually read up and found out it's not that easy, and my R134a magically disappeared the next day because it was afraid it would damage my A/C system and didn't want to put me through that. It left a really sweet note.

So now, I have a stock A/C system with some mix of residual R12, residual R134a and conversion oil, and air (it was exposed to the open air during the swap). As I understand it, the proper procedure would be to have the compressor rebuilt with new, R134a-friendly seals, replace all the O-rings in the system with R134a-friendly ones, flush out the lines, and replace the orifice tube and the condenser, then pull a vacuum on the whole thing and refill with the R134a and oil. I have a new R134a conversion kit and a new condenser and orifice tube, but I have not flushed the lines, replaced the O-rings or rebuilt the compressor, nor do I have the means to pull a vacuum on the sumbich.

Now, please check my logic. Presuming I replace the condenser and orifice and simply recharge the system from there, my A/C will work, but eventually the R134a is going to eat up the seals. To do it right, I've got to pull that damn compressor out and replace it (goodbye $150+) and figure out how to flush the lines and then how to pull a vacuum. To do it my way, my A/C works for a while, and at some point in the future I have to replace the compressor, flush the lines, etc etc. So either way, I have to do the same amount of work. Only difference is, I do a little extra work buying and replacing the condenser and orifice tube twice and buying the R134a recharge twice.

Now, given that I don't have a good place to work on my car any more and that I don't plan on keeping it more than another year or two, what's my incentive to do it the right way? How fast is the R134a going to eat up the seals? Overnight? Slowly over the next 10 years? Am I going to do any damage to parts I'd be replacing anyway if I do it the wrong way first and the right way later? Is it really critical to pull a vacuum on the system? I've only heard that on forums, it's never mentioned in the instructions, and the last time I tried to rent a vacuum device from Autozone, they gave me a brake bleeding kit.

The Dark Side of Will · Wed Apr 30, 2008 8:50 pm

You need a for real vacuum pump and a for real valve manifold to work on an A/C system the right way.

Buy all the parts, install them and take the car to an A/C shop to be charged up. They'll have the vacuum pump, valve manifold, etc to do it right.

If you switch to 134, do not use the orifice tube. Replace it with a "Variable Orifice Valve" (Google) for less performance reduction in a system designed for R12.

Fastback86 · Post by **Fastback86** » Wed Apr 30, 2008 9:16 pm

Ok, so that would definitely be doing it the right way. Pardon my stubbornness (cheapness), but I'm still curious about my logic. The AC compressor is a bitch to get off while in the car (couldn't even get to the upper bolt), hence my reluctance to do it the right way straight off the bat. I know that the recharge kit will work without pulling a vacuum on the system because I already tried it once, although I'm sure it won't work as well. However, it still leads me to the same question: if I do it the easy way now, will it really be any different later on when I decide to do it the right way? Either way, I have to replace the compressor, condenser, orifice and seals, right? Am I going to do any more damage to the system if I go with the cheap fix for now and do it right later? If I have to replace those parts no matter what, it seems to me I should get as much mileage out of them as I can before I do it. They're still perfectly fine now (albeit contaminated), just set up for R12.

The Dark Side of Will · Wed Apr 30, 2008 10:03 pm

Not sure how long R12 seals last with 134.
When I converted my Northstar car, I couldn't get the connections at the condenser loose, so I just left them. Since I still had an R12 orifice tube in it, it didnt perform great, although it did an acceptable job. My custom A/C lines (not crimped by me) ended up leaking and blowing out all my refrigerant.

That was probably over a period of about a year and a half... so R12 seals should last that long.

jelly2m81 · Post by **jelly2m81** » Wed Apr 30, 2008 11:49 pm

If you replace anything, be sure you replace the Accumulator. Alot of the oil stays in there and it is impossible to to drain a sufficent amount of it out. Also thats where most of the dirt and crud gets captured, you want to get rid of that also.

As far as the Condensor and Compressor, unless they are leaking of something is wrong with them, they should work just fine with R134a. When you take the compressor out, just turn it up on its end and drain out what oil you can.

At the very least, take out the orifice tube and clean it, I have no experiance with the variable one ( mine will frost the windshield with the stock tube).

I only replaced The o-rings at the accumulator and compressor when I put the 2.8 in ( because that was the only parts of the system I had apart), and my car with R134a is still blowing cold air 5 years later. I had to have it recharged in the first year, but that was due to a leaky hose to the oriface valve) so in my experiance, those old R12 o-rings should hold up just fine.

Fastback86 · Post by **Fastback86** » Thu May 01, 2008 12:21 am

Good deal, I had a feeling that might be the case. Also, I think I may be mixing up my terms. I think I'm actually talking about the accumulator, not the condenser. I'm thinking of the silver spherical thing under the hood near the blower fan.

The Dark Side of Will · Thu May 01, 2008 6:52 am

That's the accumulator... it's shaped more like a can.

Fastback86 · Post by **Fastback86** » Fri May 16, 2008 3:10 pm

:mumum:

Ok, so I replaced everything today. New orifice tube, new accumulator, new o-rings. I have your standard R-134a recharge and conversion bottle with fancy inline pressure gauge. According to the bottle, I should start the car, put the AC on max, and let er rip. I should then stop adding coolant/oil mix when the system hits 45psi, which should take 10-15 minutes. Well, it hit 45psi in about 30 seconds, and it sure as shit ain't blowing cold air. I was filling through the low pressure port on the accumulator. So what am I doing wrong? Shoulda had it evacuated first? Wrong port? AC system fuckzorzed?

whipped · Post by **whipped** » Fri May 16, 2008 3:34 pm

Umm, yes. Now you have an AC system with 1/3 air and 2/3 refrigerant when you need 100% refrigerant. (Or less, since it sounds like you didn't make it past 1 can)

You need to have a vacuum in your system before adding refrigerant. Also, the inline pressure gauge could be reading off the can instead of off the line. Close the valve before making readings.

Fastback86 · Post by **Fastback86** » Fri May 16, 2008 3:50 pm

whipped wrote:Umm, yes. Now you have an AC system with 1/3 air and 2/3 refrigerant when you need 100% refrigerant. (Or less, since it sounds like you didn't make it past 1 can)

You need to have a vacuum in your system before adding refrigerant. Also, the inline pressure gauge could be reading off the can instead of off the line. Close the valve before making readings.

I did close the valve, it was reading well over 100psi from the can. Alright, time to stop being a Fiero owner and get a shop to pull a vacuum on it. Any suggestions on this? Just walk in and ask them to pull a vacuum and thats it? Can I get a vacuum pump from somewhere and do it myself? The last time I asked Autozone for a vacuum pump they gave me a brake bleeder.

lucky · Post by **lucky** » Fri May 16, 2008 3:57 pm

ac vacuum pump is rare for purchase under $1000. just go to a shop and have em vac & fill it. preseason specials at most chain shops should begin anytime. return your unused cans of refrigerant.

Fastback86 · Post by **Fastback86** » Fri May 16, 2008 4:03 pm

Gotcha, I'll just tell em to vacuum and fill it. With the number of times I've done this the wrong way, it's probably fine on oil. Or will the oil vacuum out? I don't think so, but I've never asked before.

I should mention it was 95* outside when I was doing this, so that probably threw off the pressures slightly. I shoulda done this months ago. And I definitely never shoulda got that aluminum shift knob.

whipped · Post by **whipped** » Fri May 16, 2008 5:10 pm

I picked up a vacuum pump for about $100. It was hydrolocked, but a simple fix.

When they're pulling a vacuum, they will be able to tell you how well the system holds it. If you have a leak, it's better to know then than after the AC is added.

Anything will boil with enough vacuum, but most pumps aren't strong enough.

Fastback86 · Post by **Fastback86** » Fri May 16, 2008 8:25 pm

whipped wrote:I picked up a vacuum pump for about $100. It was hydrolocked, but a simple fix.

When they're pulling a vacuum, they will be able to tell you how well the system holds it. If you have a leak, it's better to know then than after the AC is added.

Anything will boil with enough vacuum, but most pumps aren't strong enough.

Good deal. I don't need the pump for anything else, so I think I'll just have a shop do it.

When they pull the vacuum, does it suck out the oil, or does that stay?

whipped · Post by **whipped** » Fri May 16, 2008 8:55 pm

Oil stays. Stuff in the oil (water) will boil off. This is good.

Fastback86 · Post by **Fastback86** » Fri May 16, 2008 9:34 pm

whipped wrote:Oil stays. Stuff in the oil (water) will boil off. This is good.

Gotcha, thanks. I'll just tell em I busted an o-ring (true story, I ripped one while I was working on it) and ask em to vacuum it and refill with 134.

lucky · Post by **lucky** » Sun May 18, 2008 2:46 am

Fastback86 wrote:... I definitely never shoulda got that aluminum shift knob.

Why not, I love mine. It's coated with frost in the winter and burns my palm in the summer....it's the best of both worlds.

Blue Shift · Post by **Blue Shift** » Mon May 19, 2008 2:35 am

lucky80 wrote:
Fastback86 wrote:... I definitely never shoulda got that aluminum shift knob.
Why not, I love mine. It's coated with frost in the winter and burns my palm in the summer....it's the best of both worlds.

There is no such thing as frost in the PRK, aluminum shift knob or not.

lucky · Post by **lucky** » Mon May 19, 2008 3:19 pm

Blue Shift wrote: There is no such thing as frost in the PRK, aluminum shift knob or not.

well, i'm in New England where it's below zero in the winter and over 100 in the summer.

flimbob · Post by **flimbob** » Tue Jun 17, 2008 2:07 pm

If the trip to the local shop identifies leaks, you will probably have to have some hoses rebuilt. The shop will offer to rebuild them for a hefty price. Instead of paying them to have it done. Ask them for the name and number of the guy who fixes their hoses. Don't ask the salesman, ask the mechanic working on your car. Chances are you can have your hoses rebuilt for a lot less if you're willing to remove them yourself. Had both the long one (front to back) and the short one (side to side ) rebuilt for roughly $80. You can then recharge yourself. Remove the pressure cut-off switch connector (located on the accumulator for 2.8l) and short the contacts with a paperclip. This will cause the compressor to kick in and accept the charge from the can. Once you have over 25 PSI, remove the paperclip and reinstall the connector. Your compressor should be cycling on and off. Continue to fill until you get roughly to 36 PSI. Enjoy that cool air you made happen.