how do i flush the a/c lines in my car. would water do the trick?? i know freon and water make for aluminum corrosion therefore messing up the lines evaporator condensor, etc. i just want to make sure that there are no metal flakes to mess up my new compressor. if i did use water how would i dry it?? thanks

------------------

Under Construction

They sell a compound specifically for flushing A/C systems, but plain old mineral spirits works pretty well.

I used a suction blowgun to flush the evaporator and lines. Use plenty of compressed air after flushing to clear the mineral spirits and be sure to vacuum the system down for a while to remove any traces.

Don't flush the accumulator (dryer) or compressor. Replace the dryer and any O-rings just to be on the safe side.

------------------

A/C flush will work well but I don't use it for fear that some of it will remain in the system. Provided that your compressor did not burn up you can effectively flush the lines by just blowing through them with compressed air but make sure that you have a water trap on your compressor output line.
I usually take all of the lines apart and blow them all out. If air will not pass through the condenser it is clogged and will need to be backflushed or replaced.
Be aure to use all new O rings, an orifice tube and an accumulator when you put everything back. Evacuate ( a must) and then charge to specs.

------------------
87GT 3.4 Turbo Best 0-60 5.2 seconds
http://turbofiero.fierojoe.com/turbo.htm

Compressed nitroget is recommended over compressed air. C.A. still has moister in it, as opposed to C.N. which doesn't. Combined with mineral spirits, it should do the trick. As someone previously advised, avoid the accumulator.

...about this orifice tube...Is there a "better" one to use for a 134a retrofit? I thought I read a finer one is better.

------------------

DECALS,FIERO SHOWS,STUFF...www.purplefiero.com

Flushing the a/c system with a solvent (as opposed to water) is the only way to remove existing oils and contaminants trapped in the oil, including debris. Blowing your system with air alone will not remove these things. Water is the one thing you don't want to use because any water left in the system will detrimentally affect the performance of the system. Water is also not miscible with the oil. A/C flush is the recommended solvent to use because traces of the solvent left in the system after flushing will not detrimentally affect performance. The manufacturers of these products will often tell you that the solvent is non-acidic or will not turn acidic if traces are left in the system after the flushing process. A lot of DIYs use lacquer thinner to flush the system because its cheap and because it readily evaporates in air. I've used this solvent with good results. I flushed a condensor core with lacquer thinner two weeks ago and removed all of the oil along with black debris that was trapped in the oil. I don't think this would have come out if I simply used air. When you flush the evaporator or condensor, place your finger over the outlet hole a couple of times to build pressure in the system and then release it. This helps to dislodge any debris that may be stuck in the passageways. You also want to do it from both sides.

Taking the lines apart to clean them like Dennis said is always a good idea.

Farknocker

Thanks for all the help fellas. Joe, an variable orifice tube is the key. I have the website on my home computer if you want it. they run about 18-19 bucks. It is suppose to help especially with at idle cooling. I will post it later tonight.

What about using denatured alcohol to flush the lines? Any thoughts? I thought it would be better than laqeuer thinner as it's not as harsh on the hands.

The proper and best flush I have used is made by FJC and is specifically for flushing AC systems. It works with either R12 or R134a and does not harm the system if you don't get it all out. It gets trapped by the drier or accumulator and just sits there. It is extremely effective at getting all the crud from a munched compressor out of the system. This stuff is used every day at the AC shop where I used to work, with great results. I was amazed at the horrible black crud that this stuff flushed out of some systems. After a good flushing, new compressor, metering valve, & accumulator or drier, the system is as good as new.

Of course, there were some condensers that simply could not be flushed & they had to be replaced. Those were few & far between though.

Find info on FJC flush stuff here: http://www.fjcinc.com/product07.htm
and here: http://www.fjcinc.com/product06.htm

I agree with Blazerguy and have very good luck with the FJC flush. Most of the time I also agree with Dennis L, but not this time. I don't like the idea of just using compressed air. It will not get the old oil out of the lines. There is, actually, a proper flush gun that uses about a 1 qt bottle that you pressurize with compressed air after you fill it with flush and the shoot straight flush through the lines. I think the poster that suggested using the suction gun gave a good idea though and I don't see why it wouldn't work except for the fact that you will put more moisture in the lines than with the correct gun. But I really don't think it would be enough to matter.

The retrofit orifice tube for the 134 in a Fiero, from Carquest stores, is P/N CTC 207325. Mine cost 19.99 but I buy wholesale. One note on the flush solvent though, it is REALLY nasty stuff to work with. Not chemically or anything, it just gets on everything and is a mess to clean up. I hate it. But I still do it. Kinda like working on Fieros in general.

8-)

John Stricker

quote Originally posted by Blazerguy: The proper and best flush I have used is made by FJC and is specifically for flushing AC systems. It works with either R12 or R134a and does not harm the system if you don't get it all out. It gets trapped by the drier or accumulator and just sits there. It is extremely effective at getting all the crud from a munched compressor out of the system. This stuff is used every day at the AC shop where I used to work, with great results. I was amazed at the horrible black crud that this stuff flushed out of some systems. After a good flushing, new compressor, metering valve, & accumulator or drier, the system is as good as new. Of course, there were some condensers that simply could not be flushed & they had to be replaced. Those were few & far between though. Find info on FJC flush stuff here: http://www.fjcinc.com/product07.htm and here: http://www.fjcinc.com/product06.htm

quote Originally posted by fierohoho: What about using denatured alcohol to flush the lines?

I tried that before. It didn't work. The alcohol does not act like a solvent with the mineral oil. They do not "blend." Its sort of like using water to flush oil out for vice versa. Kinda reminds me of the time I tried to clean a brush full of a lacquer-based paint with mineral spirts!

Farknocker

Any input on the amount (in ml) of polyester oil to put in our systems?

quote Originally posted by 84Bill: Any input on the amount (in ml) of polyester oil to put in our systems?

I don't know the exact amounts. I know that if you buy a compressor, it sometimes comes with a spec sheet that tell you to drain each component and measure the amount that drains out of it. It then tells you to add the same amount back in, plus an additional "X" ounces. You're supposed to add oil to each of the components (i.e, condensor, compressor, evaporator and drier/accumultor).

Rats! I was hoping for an approximate amount since my system is bone dry. The compressor is off the engine and I intend to clean the lines as described above. Also is it ok to use the same evap/dryer with 134?

My 84 Fiero uses 8oz. of Ester oil. The compressor manual said that the oil should be split between the compressor and the accumulator.

Hope this helps...

I put 8 oz of Ester in mine, 3 in the accumulator two in the condensor and the rest in the low pressure inlet to the compressor because I could not get it intop the compresser with it on the car.

Worked out fine.

Don't tighten the compressor connector up too tight. Book say 3 ft lbs !!
I did mone way too tight first time and it leaked.

I flushed mine using flushing fluid I got from pep boys and a flushing bottle. Messy but worth it as I'd cooked the compressor.

I put a vov valve in and new accum. blows nice and cold now.

Alternator has died now !!! Arghhhhh.

Dave http://www.ltlfrari.com

The 4season part # for the variable orifice is 38903 and the part # for the correct A/C flush is 59030. It's expensive......but it's the only thing that will do the job properly.

Oil charge stated is about what I use...just make sure to put about 2oz in the new dryer and about 2oz in the condenser.

Phil

------------------
GTDude
OVER 25 years GM experience

Thanks for the suggestions...I'll be closing up my system today.

Tell me if I've missed anything...
I've got the new 134 compressor that came with the 3400 motor.
I had to splice(yuk) the old to the new lines. I'm using barbed connectors with HEAVY DUTY clamps because no one can crimp the connection.

Flushed out all the lines and parts(except compressor) with mineral spirits. I took a chance and flushed the evaporator, it kept flowing oil when I tried to get the oil out with just air. I filled it with alot of the mineral spirits and shot air through it. It worked...no more oil!

I ordered the $30 orifice tube..ouch.
I have a new accumulator.

So I'll put some oil in each, replace the o rings, and I think I'm good to go.

I've got cans of 134 with oil...do I want to use a can or more along with the oil? Don't want to have too much oil.

You can use the cans with oil, but you need to put ester oil in the dryer and condenser and of course the compressor before you begin.

Phil

------------------
GTDude
OVER 25 years GM experience

I am going to start doing the a/c soon myself and would like to know how hard it was to change out the o rings and flush the lines. I understand that it is time consuming but just curious how many o rigns you had to replace? also is there an online resource for ac diagram for the fiero? anyone? B.