AC compressor help..Jeep XJ

Folks...noob question on AC. I would just post it on NAXJA but I've come to hate that site.

I don't know diddly about AC. Mine has needed a charge for a couple years now and I've ignored it. I finally took it to the garage and had them charge it up and it blew ICE cold for a few days until the clutch on the compressor started grinding. I saw some vids on YouTube with the exact same noise and they all said the compressor was shot. I did some research and learned that on my year ('98) the clutch cannot be replaced by itself. Had I had a '96 or older I might be in luck.

Anyway...a brand new compressor from teamcherokee.com is about $500. Since this is still a relatively nice car with only 140K miles I'm inclined to just pony up for it...I'm shooting for 300k out of her. My question is that I have read that you need to get the system purged?? before you run with a new compressor? seems like you can't just yank the old one off and bolt the new one on without risking damage? I had planned to just slap the new one on and drive to the garage for some refrigerant (or just try one of those DIY kits from Wal-Mart).

Is there anything special that needs to be done when replacing an AC compressor?

thanks

IIRC it depends on the sort of damage - if there's any chance that metal shavings got into the system, you're looking at compressor, receiver/dryer and a system purge.

XJs use sanden 5 or 7 series ( most likely a 7 series for a newer xj) - pick n pulls are loaded with $20-$40 ones.

Driers are just that, dessicants. That means they remove moisture which is what kills A/C systems. They also filter metal particles. For as cheap as they are, I'd replace the thing. Also, many mfgs won't warranty a compressor unless the R/D is replaced at the same time. Don't mess with reman compressors, they are trouble.

Before you buy a new compressor locally, check these folks:

http://www.discountacparts.com/addtocart~year~1998~make~Jeep~model~Cherokee~descript~A-C_Compressor~part~60-01315.asp

New compressor for $235.00. I bought a new compressor and R/D for the Trooper from them, absolutely no disappointments.

wow Curmudgeon....that's a good find

You might also try these guys: http://www.techchoiceparts.com/

http://www.techchoiceparts.com/ShowItem/100770-1996%20-%202002%20Dodge%20Jeep%20AC%20Compressor.aspx

(HA HA, BEAT YOU JM, MINE'S $155 NEW, YOUR'S IS 235 NEW)

I got a new compressor for my Esprit Turbo (Sanden 508) for like $130 with the clutch from those guys. I can't even get a clutch for the Rolla compressor for that from O'Reilleys.

Get a new receiver/drier when you replace a compressor. Just cause. Sucking down the system is always a good idea, but MANY have been put back together without that and everything worked out just fine.

I really, really, really HATE automotive AC systems. Especially English ones.

how does one "suck down the system"?

with vacuum.

... and some special tools. IIRC the vacuum system they use stores the evacuated refrigerant which is then either recycled or even reused.

Might be worth getting the local a/c place to do that for you, replace the compressor and r/d yourself and then go back to them and have them fill up the system.

Dr. Hess wrote: You might also try these guys: http://www.techchoiceparts.com/ http://www.techchoiceparts.com/ShowItem/100770-1996%20-%202002%20Dodge%20Jeep%20AC%20Compressor.aspx (HA HA, BEAT YOU JM, MINE'S $155 NEW, YOUR'S IS 235 NEW) I got a new compressor for my Esprit Turbo (Sanden 508) for like $130 with the clutch from those guys. I can't even get a clutch for the Rolla compressor for that from O'Reilleys. Get a new receiver/drier when you replace a compressor. Just cause. Sucking down the system is always a good idea, but MANY have been put back together without that and everything worked out just fine. I really, really, really HATE automotive AC systems. Especially English ones.

[Ronald Reagan] 'Well, ya got me there.' [/Ronald Reagan]

About evacuating the system: the biggest reason to do that is to remove moisture. For that reason, you definitely want to keep the R/D capped until just before you replace it, leave it open to the atmosphere as short a time as possible, then have it evacuated for at least 30 minutes to check for leaks and remove residual moisture.

new compressor and drier arrived today (thanks Crumudgeon). They are exactly like what is already on the Jeep. No surprises!

Now my plan (like BoxerheadTim suggested) is to install the drier and compressor myself and drive it to the garage for a professional evac and refill.

Question: what do I need to expect when I open the system to atmosphere? How much pressure are we talking about? I searched YouTube high and low and everyone on there is pulling a vacc on theirs. How do I depressurize it? Just pull the connector block off the compressor? Or hold a nail against one of the shrader valves? I've heard too that this is illegal to do but there is little chance I will get caught.

How do I proceed?

Thanks in advance

do not just release the manifold block off of the compressor a fully charged 134a system at cool temps is going to be 75 to 100 psi on avg depending on atmospheric temps. loosen a shrader valve and let it seep out slowly. then loosen the other one. once it stops. remove block from compressor remove from car. use ac flushing solution through the pressure side of that manifold. fill up system.... let sit for 10 minutes. blow out with air gun. install new compressor dryer and h-block/orifice tube)

pull vaccumm to 20 inches for 35 minutes. charge system.

Legal advise from teh intrawebz, y0, is not worth what you pay for it.

For the home mechanic to blow a charge is not illegal. I challenge anyone to show me the actual law that says it is. A professional shop can not blow a charge. That is illegal. If you work on your neighbor's car for money and blow a charge, you are probably breaking a law. If you work on your mother's car for no money, you probably are not.

Now, if you just took a hose where it connected to, say, a compressor and unbolted or unscrewed it, depending on how it was held in, and kinda undid it slow like and then stuff started coming out, well, stuff would eventually stop coming out, wouldn't it? And then you could take it the rest of the way off.

ok...update

I donned my safety glasses and using the backside of a drill bit I blew the charge at one of the shrader valves. Glad I didn't forgo the glasses...wow!

I then got out my shiny new compressor and dryer (thanks again Curmudgeon!) and installed them.

Here's my question: This Sanden compressor says on the box "Contains full charge of Sanden SP-15 PAG oil". Am I now good to go for a trip to the garage for an evac/recharge? Do I need to do anything else? I DON'T want to mess up this new compressor.

What if I postpone the garage until Monday and drive it this weekend sans AC?

Thanks

Has oil in it, so you're good to go there. Now, then, as for vacuuming it out, it is my totally amateur opinion that once you hook up that new compressor, breaking the seals and putting a new drier in, you should vacuum it out as soon as possible.

Shame on you, Dr. Hess. Advocating adding to the ozone that is causing global warming for shame.

A401cj, without refrigerant in the system, the compressor won't run, the clutch won't engage. And shame on you for releasing the Freon into the atmosphere.

R134a doesn't cause damage to the ozone layer. R12 doesn't either, according to the guy that got the Nobel prize for saying it did. R134a theoretically causes "global warming," just like your breathing, iceracer, according the the Fed's BS course.

r134a has more of a chance of causing issues.... r12 doesnt at all since it doesnt get over 18 inches off the ground.

KATYB wrote: pull vaccumm to 20 inches for 35 minutes. charge system.

The reason for pulling a vacuum is to boil off moisture in the system. You need to pull at least 29.2" for this to happen. Unfortunately, pulling twenty inches, no matter how long you do it, will not accomplish this.

BTW, while I am as skeptical as anyone when it comes to environmental "facts", both R134A and R-12 are currently considered dangerous to the environment. That's why our industry is moving away from them and in the next few years will be phasing out R134A in favor of R-1234-YF.
It may interest some of you to know that no more than 6 years ago the front runner in our research for a safe refrigerant was CO2, the gas that some (crazy) people now think is a danger to the environment.

In reply to a401cj:

My company is an official Sanden distributor. I can likely beat any other price you will find. Let me know what engine you have and I can get you a price if you want.

BoxheadTim wrote: ... and some special tools. IIRC the vacuum system they use stores the evacuated refrigerant which is then either recycled or even reused.

In a charging station, the recovery process is what reclaims the refrigerant and recycles it. Evacuation refers to the vacuum process used after recovery to remove air and boil off moisture from the system.

well...I took it to the charging station this morning. I'll let you know how it goes.

bravenrace...thanks for the heads up on the low cost compressors. I'll keep that in mind next time.

Looks like cool weather here in the east for the next few days so just in time

In reply to a401cj:

Crap, sorry, I somehow missed your post before this last one. I wouldn't have said most of that if I had known you had already taken action.
One thing related to one of your questions. The oil is only there to lube the compressor. It has no other function in the refrigeration system. And too much oil degrades performance. If the compressor comes with oil in it, and all Sanden compressors do, you never need to add any additional oil unless you have an extremely long suction line, or a suction line with a low spot in it's routing. The low pressure in suction lines can sometimes allow the oil to fall out of the flow of the refrigerant, and it can also get trapped in looped areas. WIth normal hose lengths this still isn't an issue, but with long suction hose runs of about 12 feet or more, then it's sometimes a benefit to add a few ounces of oil.
When repair work has been performed, like replacing a heat exchanger, it's a good idea to add a few ounces to make up for whatever may be in the component. When refrigerant is recovered using a machine, it will take a certain amount of oil out of the system. You can drain that and measure the amount, and then just add back in the same and your good to go. None of this really matters to you right now, but since you asked about oil I thought I'd mention it. Good luck.