While I am very swift at the auto mechanics, the ac system escapes me as it does most mechanics! My compressor is bad on my 99 s-10. I have been reading up on ac systems, and I understand some basics (I also studied chemistry and physics in college, so I understand the theory).
Can I simply remove my compressor, put the new one in and recharge the
system with store bought r134??. The AC shop wants $1000. Too much for
for my 99 chevy. Oh yea,....I live in Atlanta where summer is unbearable
with out AC!

Advice is always appreciated!
Brian

You could. The real problem is after it's reassembled you need to vacuum evacuate the system to insure there is no water in it. Living in Atlanta, that would come from atmospheric humidity. In the system, the water will freeze stopping the R134 in its tracks. After the system is pumped down then new R134 and appropiate lube is added till the system is back to capacity. Not difficult to to but the vacuum pull down takes special equipment.

You're also up against legalities, just dumping your existing R134 into the atmosphere is illegal and the stuff is considered contaminated so can't be reused, therefore, it has to be disposed of in a legal fashion which is probably a large part of the 1000 bucks the shop wants on top of labor to R&R the compressor, cost of a new compressor, cost of evacuating and cleaning the existing system, cost of refilling it with refrigerant and lubricant.

Bogie

 

Harbor freight sells a vacuum that hooks up to your compressor. It is like $20 and it is just for your R134 AC system. It worked really well on my friends truck. He bought the gauges to so we could see the High side and low side. They were $40. Less if on sale. Good stuff for Chinese junk. Pays for its self the first time you use it.

 

AC vac pump

I made mine from and old refrig. compressor. Put a brass fitting on the suction line with a compression fitting for the tubing and the other end had the threads for the hose going to the gages. Works great and didn't cost anything except the brass fitting. Just make sure that the other side of the fitting is a perfect fitting for the hose. O yes, I wired it for 120 volt and installed a switch for convenience (mine)
I start it up, open the valve and pump for about 5 min. or so. Close the valve, stop the compressor for 10 to 15 mins. then start it again and open the valve for another 10 mins. then in stall oil and freon.
It may be wrong, but sure puts out some cool air.

 

Vacuum Pump

Ya, it is a good idea to get a vacuum pump to remove the moisture from the system. If there is any air left in the system, the gauges won't give you the correct readings once the R134 is added. The gauge readings are accurate only if there is but r134 in the system. Any moisture left in the system combines with the oil & produces an acid which will go to town on the insides of the system in short order. The most immediate problem may be ice forming at the metering valve and in the evaporator. The oil you have to install is important and must be correct for the r134. Never used an open container of oil because it has the ability to absorb moisture from the air... a bad thing.

Don't think you can use the left over oil for anything because it is only a lubricant when under the influence of r134.

The first time you draw down a vacuum, leave the gauges hooked up and check to see if the vacuum holds after an hour. This will tell you if you have a leak in the system and how bad it is. Break the vacuum by adding a shot of r134 and deep vacuum again.

The next time you should go ahead and add the oil and r134 to specs.

 

Im from south west texas.We have about the same weather.It's bad on ac compressors.It would be in ur best interest to replace the orfice tube, acc/dryer.Most companys require it so they warranty the comp.If u have the money us a ac delco comp.They seem to last longer than the others.Stay away from auto zone comps.Be sure and replace all the o rings u take off and coat the new ones with the new oil.If your comp went out there is metal in the lines.(which there always is due to break in of the comp)But on a larger scale.So u need to flush the lines.By some ac flush or u can us brake cleaner.Then use compressed air to blow out the lines.Let it dry good.When u buy the refrigerant get it plain with NO STOP LEAK.(some parts stores keep this behind the counter,so ask if u cant find it)It's ok if u get a refrigerant with uv dye in it.If not u can get oil with dye or dye separate.U want this so u can find leaks later if need be.Be sure and put oil in the new comp before u start working on the car.This will give it time to settle.Pour a little in one of the holes on the comp.Turn it slowly till it reaches the other hole.Then put it on a table with the clutch down and cover it with a rag while u work.If it;s hot *** hell when u go to fill the system.U will want to run water threw the condenser to get the pressure readings right.Also u might have to jumper the ac cycle switch so it will take the first can.Unplug the connector and us a paper clip is a easy way.Hope this helps

 

Be sure replace the dryer and expanson valve too.

 

The reason the shop wants $1000.00 to do this job is that the proper recovery, evac, recycle and recharge machines cost big $$$$$. Another cost is the labour to r&r the compressor, orifice tube and suction acumulator. You MUST replace the suction acumulator and orifice tube. Not only because of the warranty issue, but because as mentioned, there will be contamination from the compressor failure. One word of caution, don't remove the plastic plugs from the acumulator until you are ready to install it. As little as 30 minutes exposed to a humid atmosphere will saturate the dessicant material in the acumulator, rendering it uselss. It can also swell the "bag" the dessicant is in, and cause HUGE problems later if/when the bag lets go, and all that dessicant gets pushed through the whole system. Also, after you have mounted the compressor (with the proper amount of oil poured in it, the instructions will tell you how much), turn it over BY HAND at least 10 times. This is done to purge the compressor of any oil that is in the cylinders. If this is not done, there will be compressor damage done immediatly upon start up.

 

You'll need to change the orifice tube and accumualtor.....But you'll also need to either change or flush the condenser. The orifice tube "should" have caught anything before it got into the evaporator.

I'v only done one of these...and it was on a S10 94 i believe....(bbtw remember to take the plug out of the side of the compressor and fill it up....and keep track of how many oz of oil and 134 you put in....

Just remember if you do this.....then you have no warranty on the work....even if you get it together and something[/u] goes wrong....even if you get everything again (under warranty) theres still the labor of doing it.

Something to think about......

 

Thanks guys!
Is there any way for me to capture the 134 in the system and re-use(the system is basically full), or is that where the specialized equipment comes in?
Should I take my truck somewhere and have the system evacuated and then
go from there ?
Brian

 

Thanks guys!
Is there any way for me to capture the 134 in the system and re-use(the system is basically full), or is that where the specialized equipment comes in?
Should I take my truck somewhere and have the system evacuated and then
go from there ?
Brian

You can dissasemble & flush the system yourself. The assemble your parts and take to get it vacuumed down and filled. I wouldn't reuse any of the old coolant/oil because of contamination.

 

If you have the proper equipment, the old refrigerant can be re-used. The R134a itself won't be contaminated to the point that it cannot be filtered with the right macine. However, If you do not have the $5000+ recover/recycle/evac/recharge machine, there is really no way for you to do this. Also, without a recovery machine, there really is no way for you to capture the old refrigerant. So you will need to have this done, and likely get new refrigerant as well. DO NOT REUSE THE OLD OIL! it is NFG now, and must be replaced. The flush proceedure needs some other tools, not just some solvent and a blow gun. Compressed air + R134a + solvent = BOOM! Not good.

 

If you take it to a shop....you MIGHT get them to evac the system for free.....then you can go about flushing it, changing your parts, and installing new oil and 134.

This at least saves you from letting it into the atmosphere.....Al Gore might come after you if you dump it.

Just remember to install the correct amount of oil and 134. and get the system CLEAN!!! you can buy the flush at most auto parts stores.

 

I've been through this a couple of times with my old truck. Its not that hard, but there are a lot of steps.

If the compressor failed internally, the seals will break up into black granules. These granules will quickly plug up the system if they are not flushed out. If you are lucky, the compressor may have quit due to other problems and may not have internally self-destructed.

- Check the pressure first with one of the cheap gauges from the auto parts store. If pressure shows zero, then you can open it up without releasing any R134. If there is still positive pressure, you need have a shop recover the R134. This is very easy and they should not charge very much (1/2 hour labor?).
-Then find the orifice tube fitting and remove the orifice. If its plugged up with black granules, then quite a bit of work is needed. Your condenser should be replaced if its a parallel flow or piccolo style condenser (openings are too small and its very hard to get the granules out) If its a serpentine flow condenser (one big serpentine tube), you might be able to flush it out. If any A/C line has a muffler, the line probably has to be replaced because its hard to flush the muffler. You should be able to clean and flush the evaporator and all the lines.
- If the orifice appears to be clean, or just a little oily, you can probably get by with just flushing all the major components with A/C flush, and then blowing them dry.
- After a complete flush of all components you will reuse, install a new orifice, new filter/drier (or accumulator), and all new O-rings (use green O-rings). Install the new compressor and belt. Add the recommended amount and type of oil to the system (probably PAG for a GM system), unless you buy a compressor that is already filled with oil.
- Take it to an A/C shop and have it vacuumed for 30 minutes at 30 inches of vacuum. This will remove the residual moisture from the system.
- Have them charge it with R134 of the recommended amount. I would think that a shop should vacuum, charge and leak check the system for about 1.5-2 hours labor, plus the cost of the R134.
- While its running, have them leak check it with an electronic detector.
- A/C should now be fully functional (we hope).

Bruce

 

WOW
Thats the most response i've ever got from hotrodders!
I am trying to sell the truck, and AC is big in Atlanta.
I don't want to rig it to work for a minute just to sell the truck.
( I don't want to rip anybody off)
I'll probably drop the price and sell it as is ...ouch.
Its a nice truck! minus AC.

All Gore might should kiss my butt.
But I am a law abiding man, and.... I don't want to send r134 into the
air we all breath.

my $4000 dollar truck now is for sale for $3000. Anyone interested?
(1999 chevy s-10, fleetside, single cab, short bed, 4.3L VORTEC HO{its fast!} 110,000
original miles, plenty new parts,flip top tonneau cover,...etc)....

My Hotrod is my 88 Silverado, which also needs AC. (I should do a seperate
post). I accidentally released the refrigerant into the air when i did my rebuild.
(3 years ago)I thought the system was empty b/c the condensor was smashed in. I was wrong.

NOW THAT I HAVE THE ATTENTION OF THE AC GUYS....Can I convert the 1988 system over to r134? I read that the system was set up with future refridgerants in mind. I am willing to go the extra mile to get AC in my 88.


Is my compressor toast? (all the oil and gas leaked out at once), I put the
line back, and now its been 3 years. LMC sells all the parts.

Thanks again everyone!
Brian

 

My suggestion: Replace the compressor and dryer. Take it to a shop and ask for an AC service. That typically means they remove any old refrigerant (which you won't have), vacuum it out, test the vacuum, then recharge it. My AC shop charges $79 for that.

One thing you'll need to do is add lube to your compressor. R134 uses an Ester-based lube. Each compressor is a bit different, but make sure to add it when you change compressors.

So for $79 plus parts you have all you need for icy cold AC

 

last question

can i pull apart 1999 chevy AC compressor and rebuild it ?

 

fast response

my system was full. and I don't know enough to know what that means.
High side is really high. and the comp clutch kicks on if i feed it r134.

 

Theoretically, yes, but don't even think about it. New compressors can be had for $150, but until you trial-and-error rebuilding your own, it might cost way more than that.

 

Im trying to sell the truck, and i don't want to rip anyone off.
I'm looking at a comp on ebay for about $150.

I'm starting to think about dropping the price tag for the truck....

I'm a chevy fan, but this AC quit before it should have.

 

Im trying to sell the truck.

Just do what I do when I sell a car without AC.....wait till winter time....

NEW TIRES - GOOD HEATER sells everytime

 

my system was full. and I don't know enough to know what that means.
High side is really high. and the comp clutch kicks on if i feed it r134.

How high was the high side, and how low is the low side? Is the compressor noisy, like ticking, clicking, or growling? If not, and your system is full as you say. Spray some water on the condenser, and check your pressures again. This will bring the high side down below the high pressre switch. Also check to see if the cooling fan/fans are running with the A/C on. It could be possible the A/C quit because of a fuse, or relay.

 

On converting your '88 - I'll tell you what I have done on my '75.

For my first conversion I tried to use a rebuilt A6 compressor (stock in '75; a real boat anchor) and convert the system over to R134. I flushed the system and replaced some hoses, and then tried variations of orifice sizes (R134 works better with a small size in most cases) and variations of charge, but it was never really that cold.

When the rebuilt A6 died, I decided to do a better conversion. I used a new Sentec compressor (aluminum, one piece mount, much lighter), new parallel flow condenser, high pressure cutoff, new hoses, and Ford blue orifice. When charged with R134 at 75% of the original R12 charge, my vent temps are about 35 degrees at an ambient temp of 85-90 degrees.

I can give you an idea of how you might have to "play" with the system to find the best cooling when you do a conversion. When I first charged the new system, the AC guy suggested using the same R134 amount as the original R12, and to use the GM white orifice (stock size). I had vent temps of about 55-60 degrees, at best. When I switched to the Ford blue orifice and 75% charge, the vent temps then dropped to 35 degrees. The new orifice was only about $2, and I used 12 oz less refrigerant (saved a little). The primary cost of experimenting was my paying the guy to evacuate and recharge the system multiple times.

Bruce

 

On converting your '88 - I'll tell you what I have done on my '75.





When I first charged the new system, the AC guy suggested using the same R134 amount as the original R12, and to use the GM white orifice (stock size).
Bruce

That A/C guy has no clue as to what he is doing. Even the conversion chart is not accurate to every vehicle. All of the conversion kit's I have ordered have come either with a brown, or blue fixed orifice, vehicle specific.

When converting you have to closely watch your pressures to achieve maximum cooling.

 

I think you missed the point - when I made my "conversion" the only stock item left was the evaporator. There were so many components changed that the normal conversion chart wasn't worth much.

The AC guy's initial rationale was that since I switched from the stock serpentine condenser to a very large parallel flow condenser, and also switched to a much newer design compressor, he would first try a stock GM orifice size and refrigerant charge. This was different than most conversion recommendations, but the conversion charts also assumed I was still using a stock compressor and serpentine condenser.

I agree, he could have watched the pressures, but I have not yet found an AC guy who really understands what the pressures mean and is therefore able to use them to tune the system as it charges. The AC techs are taught to plug in the machine, set it up to evacuate and recharge with the set amount, and just wait for it to get done. In most cases they will not let you in the shop bay (supposedly for insurance reasons) so that you can watch the pressure yourself. If the final pressure is within a reasonable range, they consider it good enough.

It is very similar to the problem you have with many mechanics today, who simply run through the troubleshooting procedures without understanding what they are measuring. I did find a couple of shops that would work with me to make the custom hoses and fit other parts, and they were pleasant exceptions.

Bruce

 

Gauge pressures with the engine between 1600-1800, normal cruising speed, High side as close to 225 as you can get, Low side between 26-28 just above the low pressure cut off switch, will get you low 30's out of the vents. I've had some Fords, one of if not the best systems out there, that you could see your breath while talking to anyone.

After I have reached this point, with the system blowing COLD, I then check my scale to determine how much freon was used, to charge for.