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New guy here, about to overhaul A/C system

PatrickGSR94 on Mon July 18, 2011 5:42 PM User is offlineView users profile

Year: 1996
Make: Toyota
Model: Corolla
Engine Size: 1.8L
Refrigerant Type: R134a
Ambient Temp: 90°F+
Pressure Low: -
Pressure High: -
Country of Origin: United States

Hello all, I've been searching around the net looking for tips and procedures on A/C flushing and recharging as I'm about to do a complete overhaul of the system in my wife's 1996 Corolla.

A little history: the car has about 225,000 miles and has always had ICE-COLD A/C for as long as I can remember. Then on Wednesday 2 weeks ago the car just started blowing hot air suddenly about 15 miles from home. I got to looking at it, hoping it was just a fuse or the belt or something. No dice. Looks like catastrophic compressor failure from the looks of this melted hard plastic that the clutch was spraying out everywhere:

So I went ahead and ordered a brand new overhaul kit from Discount AC Parts consisting of a brand new compressor, receiver/dryer, expansion valve, o-rings, and an 8 oz. bottle of PAG 46 oil.

While waiting for the parts to arrive, I went ahead and started removing the compressor and some of the lines. The back side of the clutch pulley looked just nasty:

Also after the compressor dropped down to the floor I noticed it made a couple piles of dust. I had noticed a similar pile of dust on the floor starting a couple of months ago, but I had no idea where it was coming from at the time. I suppose that was the first sign of the compressor going out:

I looked down the ends of the lines I removed (each line coming off the compressor and the low-side line from the evaporator to the compressor) and they all looked really clean inside. The oil dripping out of the lines also looked very clean:

I still plan to flush the lines and everything. Today I purchased a new A/C belt (cut the old one off last week) and a 25-oz. bottle of pour-in DURA-II solvent flush, along with a Typhoon blow gun to use with my shop compressor to get all the flush solvent out of everything.

The main thing I'm worried about is whether I should replace the condenser or not. Since the lines and the oil that came out of them all looked clean, I'm hoping the compressor didn't contaminate or plug the condenser or evaporator. Also I'm not sure whether the condenser on this car is the type that can be flushed or not. How can I tell? Can I just look in where the lines attach to the condenser to determine whether it's junked up or not? And what about the evaporator? I will be pulling that out of the car to replace the expansion valve. Should I try flushing that?

The other main question I have is what brand of R-134a should I buy? I know most auto parts stores will try to sell me the stuff with "stop leak" junk or the stuff with additives that supposedly increase A/C cooling performance. IMHO that all sounds like a bunch of hogwash. So should I just buy the cheapest, plain, straight R134a I can find or are certain brands better than others? Or is the only difference between brands just the additives?

Anyway, I'll be renting all the recharge equipment from AutoZone later this week. All my parts came in today and I'm hoping to have most of it installed by this evening. I just need some suggestions on the condenser so I'll know if I should order that or not. Money is SUPER SUPER tight for us which is why I'm doing all this myself, so if I can avoid another $100+ on replacing the condenser, if the old one is still good, that would be a big help.

*edit* the oil that came with the kit is Meridian premium DEC PAG 46, just to be clear.

Edited: Mon July 18, 2011 at 5:55 PM by PatrickGSR94

mk378 on Mon July 18, 2011 6:16 PM User is offline

Did the compressor seize, or can you still turn the clutch plate (which drives the internal workings of the compressor) by hand?

If the compressor did not seize and the refrigerant didn't leak out, it was just an external clutch and/or bearing failure. In that case, I'd suggest a conservative procedure of just replacing the compressor and receiver drier, add an appropriate amount of oil (from manufacturer's best guess published specs). No flushing, and don't mess with the expansion valve either.

In any case, while waiting for parts to arrive, slap the old compressor back on and make up the lines so the system is closed up and sealed against moisture and dirt.

Definitely use plain R-134a no additives. Any major brand is OK, e.g. DuPont, Genetron, or National. You could use one can with UV dye as it appears there is none in the lines now.

Edited: Mon July 18, 2011 at 6:19 PM by mk378

PatrickGSR94 on Mon July 18, 2011 7:38 PM User is offlineView users profile

Well the compressor manufacturer requires the system to be flushed to maintain warranty. I've already had some of the lines sitting in the garage for a week so those need to be flushed anyway.

*edit* the clutch does turn by hand. The pulley itself is a bit more difficult to turn. So I could just flush the lines that have been off the car and not worry about flushing the evaporator or condenser? Why should I not replace the expansion valve?

Edited: Mon July 18, 2011 at 7:45 PM by PatrickGSR94

PatrickGSR94 on Mon July 18, 2011 8:53 PM User is offlineView users profile

Was just about to mount up the new compressor when I saw that it has a different plug on it than the factory plug. Perfect!

iceman2555 on Mon July 18, 2011 9:55 PM User is offlineView users profile

If you are referring to the wiring connector.....simply remove the factory unit and replace the aftermarket compressor connector ....simple!!!!
Replace the condenser!
The clutch failed due to lack of lubricant in the compressor. This clutch burn out has been an on going failure due to this condition. A by product is also debris in the condenser. Have seen this more than once. Spend the bucks for the new condenser.

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

PatrickGSR94 on Mon July 18, 2011 10:34 PM User is offlineView users profile

Okay so I've had one person here and one person on a Toyota forum say I only need to replace compressor and drier due to what appears to be a failure external to the actual compressor internals/oil/refrigerant, plus the fact that the lines are nearly spin'n'span inside. You say the condenser needs to be replaced because of debris in the system, yet I have not seen any indication of debris anywhere yet.

Also I removed the cover plate from the old compressor and the inside looked 100% clean. Soo not sure what to do.

I could cut off the connectors and swap them but would the warranty still be intact, considering that I already e-mailed the company and sent them pics of the 2 connectors? I was hoping to have this thing installed and all closed up tonight but I guess I'll wait until I hear back from them.

Edited: Mon July 18, 2011 at 10:36 PM by PatrickGSR94

mitchedo on Tue July 19, 2011 7:48 PM User is offlineView users profile

Since you're not going to re-use the compressor, take it apart and see if it failed. I just had the same issue on my 2006 Sienna -- melted down clutch. There are several possible reasons the clutch could melt down and the compressor (and the rest of the system) be perfectly fine. The service manual says if the clutch receives less than the optimal voltage, it can cause weak engagement, with resultant slippage, with resultant heat buildup, with resultant meltdown.

Also, someone here suggested a possible shaft seal leak gets oil into the clutch, causing the clutch slippage, with the same heat buildup and meltdown.

I took my compressor apart, and it looks absolutely fine. It turns very easily by hand, and there is absolutely no sign of any kind of particles anywhere. The system also cooled perfectly well at 108 degrees in Ft Worth the day before the clutch failed, and at 102 degrees near Tucumcari just before the clutch failed.

Since it's such a nightmare to get to things to flush them, I'm going to take a chance and just install the new compressor and receiver guts. I'd rather be out the $350 for the compressor than spend 3 days removing the dash unit and rear unit so I can take it apart to look at the expansion valve and flush the lines. If I kill the new compressor, then I'll spend the time next time to pull the system apart. ...and I'll buy all my stuff from AMA next time.

Home of the "Tunex Suburban Disaster"

Edited: Tue July 19, 2011 at 7:54 PM by mitchedo

PatrickGSR94 on Wed July 20, 2011 11:10 PM User is offlineView users profile

Yea pretty much the same for me. I removed the upper plate with the relief valve and hose connections and found the inside of the compressor completely clean.

I just pulled a vacuum on the system with all the new parts and oil, and got darn near 30" Hg on the gauge after an hour. It sat right at 29" most of the time and got to about 29.75" when I shut it off. Now it's holding a vacuum for a bit, will check it after 30 minutes.

I think I got lucky and got what appears to be a near brand-new Mastercool gauge set from AutoZone. Unfortunately I got home and realized it didn't have the quick connect fittings for the ports on the car, so I had to go back and they got them out of another kit they had which looked much older than the kit I have. Oh well, getting it done now and hopefully will have cold air by tomorrow.

Edited: Wed July 20, 2011 at 11:11 PM by PatrickGSR94

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