Question about auto A/C

Richard Casto · **Posted:** Tue Jun 15, 2010 2:18 pm

I believe I have to replace the compressor clutch on both of my Civics (odd that both are having similar A/C issues at the same time).

I have zero A/C experience, but I am assuming I can take the cars to somewhere local and have them evacuate the system before I remove the compressor (you have to remove the compressor to replace the clutch as best as I can tell).

I plan to seal off the ports on the compressor as well as the lines when I remove it to try to prevent moisture from getting into the system while I do this work. When they evacuate the system, I assume they don't leave a vacuum and let it return to normal atmospheric pressure? If so, do they just let regular (humid) air in, or do they use nitrogen or dehumidified air? Or do they just figure they will remove the moisture in a second evacuation that will be done prior to charging the system (even if it may damage the receiver/dryer while the system is uncharged). I may end up replacing the receiver/dryer anyhow.

Any recommendations on local (Durham) place who can evacuate and then later recharge the system?

JamesShort · **Posted:** Tue Jun 15, 2010 2:37 pm

I've always replaced the receiver/dryer when I break an a/c system apart...they generally are of negligible cost compared to the cost of the a/c job you are currently working on

. And yes, when they evac the system, they'll bring it down to atmospheric pressure and not pull a vacuum on it.

Sean O'Connell · **Posted:** Tue Jun 15, 2010 5:39 pm

there is likely to be a little bit of pressure left in the system when you take the compressor off because some of the refrigerant will be left behind and expand, so dont be shocked when it pop's apart. dont worry about plugging it off, just replace the dryer before you get it charged and the vacuum will take care of the rest.

Richard Casto · **Posted:** Tue Jun 15, 2010 9:25 pm

Thanks for the comments.

Anyone have any recommendations on who can evacuate the system for me? What should I expect to pay for that?

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

Couple of comments --

- If it's just the clutch, you may not need to open the system at all. On some (all?) cars the clutch can be unbolted from the compressor without pulling the lines, if there is room. If not you may be able to unbolt the compressor and swing it up or down to get access to the clutch

- If you do need to pull the lines you could just vent the R134a to the atmosphere at one of the schraeder valves. May not be a popular option with the greenies, but not a huge deal.

- Having someone pull the r134a into a recycling system would be ideal. Any good indy shop should have the recovery unit and will leave the system at zero (or close) pressure. I recently used Joe's auto in Cary. Be warned most mechanics charge a lot for AC work, even just pulling the existing refrigerant out will likely cost an hour of labor, $80-100. I'd call around, or check google maps for reviews of indy mechanics in your area.

- Is the clutch broken or just noisy? You might be able to rebuild them also.

Aaron Buckley · **Posted:** Wed Jun 16, 2010 11:28 am

To Mike's point, if the clutch is magnetic, it may not need to be replaced, just re-shimmed. PM me if you want info on that, for I did it on my Volvo. - AB

Richard Casto · **Posted:** Wed Jun 16, 2010 3:35 pm

Thanks for all of the comments. Let me give you some extra info...

Blue car (my daily driver). I have debugged it down to the clutch. Basically I can confirm that when the electro magnet is energized, it is not engaging the clutch. It basically doesn't do the normal "click" that you can get when the clutch engages. So I am pretty much assuming it is the clutch. The factory manual has tests to troubleshoot the clutch, but the clutch has to be removed to go beyond what I have done. Once out I will continue to troubleshoot, but unless it ends up being something simple, I will probably just go the easy ($$

) route and buy a new clutch. That is about $110.

Silver car (Tina's car). It is a slightly different story. A/C works, but on Monday she called saying car was making an odd sound. It was a sound I had never heard before. It had an engine speed rhythmic sound, but it was an odd combo of a knock and bearing noise. The sound also wasn't constant. It would come and go and seemed to maybe only be triggered at the right RPM (some type of harmonic would get it going?). It also wasn't super loud, but you could hear it. Sound was generally from the accessory side of the engine, but I was not really clear exactly where it was coming from. Since it was something I had never heard before I was a bit freaked out.

Using a mechanics stethoscope, it sounded like it was coming from the A/C compressor. It seemed that the sound would almost go away when the A/C was turned on, but was worse when the A/C was off. I remove the A/C belt and the sound was 100% gone. (Note to self. I as type this I need to check the idler pulley for the A/C belt to make sure it doesn't have a bearing going bad)

My assumption is that it's either the compressor, clutch or both. Since the sound was almost gone when the clutch was engaged, I am thinking it is more likely to be a bad (or dying) clutch. However, since I don't know much about how either the compressor or clutch sounds when dead/dying, I can't say for sure. I am on the fence about buying a new compressor clutch combo or just clutch. I don't want to have to assemble it all and then find out I didn't fix it. A compressor and clutch combo is about $300 and as mentioned a clutch by itself is about $100. I am leaning toward all new compressor and clutch on the Silver car.

Mike, to your question about not removing the compressor to get at the clutch. As best as I can tell you need a wheel puller to remove the clutch. And I don't think there is enough room to even remove the clutch off the shaft even if you didn't need a wheel puller. This area is so tight that I am barely able to get a single hand in the area let alone tools. I can tell its going to be fun getting the compressor out due to lack of space. I also expect it is going to be fun getting the dryer out as it is also buried.

Scott Lusted · **Joined:** Tue Oct 27, 2009 9:52 am **Posts:** 215

Also go ahead and replace all the oring seals in the system. Last car I had needed a new compressor since it was leaking. So I tested the valve and you could tell the pressure was really low so I just vented it. A tiny piiiissst later, yankin parts.

So replace all the orings seals, drier, and orifice.

I ended up taking it to my father in law to charge it. He first put the system on a vacume pump and ran it for a good 30min or so. This was done to get any moisture out of the system and a final leak check.
From there added oil and charge. Worked great after that!

-Scott

Richard Casto · **Posted:** Wed Jun 23, 2010 11:23 am

Parts came in yesterday evening. Even driving with the windows open on I-40 my car feels like an oven.

I need to sych myself up to work on this over the weekend.

Vincent Keene · **Posted:** Wed Jun 23, 2010 11:47 am

Scott Lusted wrote:

Last car I had needed a new compressor since it was leaking.

I had the same problem, but luckily I was advised that the compressor can be fixed for next to nothing. As it turned out, the o-ring behind the pulley was indeed the culprit. I bought an o-ring from CQ and we had it fixed in less that an hour. Save myself about $750 in the process.

Richard Casto · **Posted:** Fri Jul 09, 2010 4:49 pm

Ok, one of two is done. I replaced the compressor, dryer and related o-rings on Tina's Civic (along with the busted catalytic converter) today and had a local place evacuate and recharge the system. Seems to work great.

I will tackle my Civic tomorrow. It is just getting a new compressor clutch, dryer and o-rings.

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