So, I have been gradually replacing things that make noise on the engine. Idlers, alternator, PS pump. Then it came the AC compressor's turn.

For anyone who doesn't want to read the story, here are the specs

Oil:
PAG46. 8 ounces.
This is total capacity assuming the system is empty. If you replace a single component the manual has a chart for how much oil to add for each.

Refrigerant:
R134a. Per the manual, 1.70 lb/0.77 kg, per the sticker on the car 1.63 lb/0.74 kg.
I went with the sticker.

Torque:
Hose to compressor bolt 33 N,m (24 lb. ft.).
Rear compressor bolts 25 Nm (19 lb. ft.).
Front compressor bolts 50 Nm (37 lb. ft.).

I first thought to replace the bearing. Bearing is cheap, like $30. However, you need like three special tools to get at it.
Then I realized the clutch plate is a bit rusted and scrapes. The clutch kit is like $80 (you can get cheaper, but I don't really trust those)
Then I thought that given that the AC system is totally empty, the compressor seals are probably dried out.

Rock Auto had a kit with the compressor, the accumulator/drier, and the orifice tube for $216. So I bought that.


I got a little bit screwed on that. They said it came pre-filled with oil, but when I got it there was a big sticker on it that said it contains shipping oil that must be drained. The oil didn't look like the regular oil, so I drained it and bought the proper oil.

Per the manual the oil charge is 8 ounces of PAG 46 oil. 8 ounces happens to be the size of the bottle that oil comes in and PAG 46 is like the most common AC oil you can find. Literally any parts store has it. And it's less than 10 bucks.

With all that in hand I got to unbolting things.

First, I would highly recommend removing the battery completely. Not just for safety, but because it makes it all a ton easier. Also, unbolt the ground lead from the battery cable. You will need to move the negative cabe and this will be necessary.

Then, unscrew the fittings on the accumulator hoses. The fittings are some stupid SAE sizes I mostly don't have. I think only one or two I had a wrench for, and it was something like 15/16. I hate the US customary measurement system.

Fortunately, the AC fittings are pretty low torque and don't tend to get stuck, so I made do with a pair of adjustable wrenches. Always, always, always use two wrenches. Those aluminum tubes aren't all that strong and you can twist them easy. No big deal on the condenser, but on the evaporator you will probably kick yourself hard enough to have a black and blue buttcheek.

With the upper hoses loose you can loosen the 10mm bolt that clamps the accumulator in the bracket and pull it out.

With that out of the way, unplug the pressure switch and the compressor clutch switch. You probably should unscrew the pressure switch at this point. It has an o-ring, and you should probably replace it.

Then, you can undo the fitting on the evaporator-condenser line (lower one of the two). The orifice tube will be in that line.

I would also remove it from the condenser - it's a clamp with a 10mm bolt. Even if you aren't replacing the condenser it is nice to keep that tube out of the way when you do other stuff.

When I pulled my orifice tube, it looked like this:



That is pretty bad news. The stuff on it is metal flakes, likely from the compressor eating itself. I was going to replace the compressor anyway, but this means that the whole system has trash in it, including the condenser. Condensers on these (and many other cars, especially newer) can't be flushed. The tubes are too small, and you can never get all of it. And if you don't, you will contaminate the nice new components you put in.

So, it was off to the parts store. The condenser for the 4th Gen is $119 anywhere, but O'Reilly has to order it and AutoZone had it in stock. So, AutoZone it was. Also, I grabbed an o-ring kit, a can of AC flush, and rented a flush kit.

The o-ring kit turned out to be important. I already had a generic AC o-ring kit that is in every parts store next to the AC stuff, but this system has a couple of sizes that were not in it. They were in the model-specific kit AutoZone had.

Back to unbolting.

After (obviously) taking the belt off you can get to the compressor mount bolts. There are three 14mm bolts on the front - top, bottom, and drivers side. There are also two 13mm bolts on the back. Those are of the devil. The engine mount is in the way, the exhaust won't let you get a ratchet on, you can't see a damn thing... The outboard bolt is the worst. Fortunately, they are pretty low torque - 19 ft-lbs, and once you get them loose they spin easy. I got the outboard one loose with a 3/8 breaker bar and an extension, the bar was smaller than a ratchet and just barely fit.

I suggest this order:
Take out any two front bolts completely. Top and side can be reached from above easy.
Take out the inboard rear.
Loosen the outboard rear.
Take out the lower front.
Unscrew the outboard rear while moving the compresor forward.

While you are underneath to mess with all this undo the lower condenser hose.

Once the compressor is loose go topside again and wangle it out, hoses and all. This is where you will need to move around the negative battery cable - it will likely be routed in some stupid way between the hoses.

With the compressor out you can remove the bolt holding the hose manifold on the back of it and take the hoses off. Watch for oil dripping out.

After this I took out the condenser. It's pretty easy since you have the hoses off already. Take out the airbox, the rubber donut holding it to the intake, the three bolts holding the radiator bracket. Then, reach in behind the hood latch and unsnap the two pop fasteners on the plastic flap. The condenser is held to the radiator with plastic brackets molded into the radiator and will come out if you just pull up on it (parallel to the radiator, not away from it).

New condenser goes back in in reverse.Clip the plastic to it first and remember to guide the flap behind the hood latch like it was. It was a little tight and I had to tap it with a hammer handle, but it fit fine. Weirdly, it is smaller and lighter than OE. Weight reduction, I guess. I am such a racer...

Then you can put the bracket back on and get back to the other stuff.

This is where I broke out the flush kit. It's kinda stupid.


This is an aluminum bottle with a hose. It comes with what is effectively the same as the cheapest Harbor Freight blow gun, but with a slightly bigger rubber tip. You are supposed to pour solvent inside and pressurize it with shop air. Except it doesn't come with any air fitting. You need to supply your own. And this nonsense is $68. You can get a better one with a gauge on Amazon for $20. The saving grace here is that it's a "rental", so you can use it and return it.

The bottle of flush solvent is good for about two fills of this thing. I used one to flush the evaporator, and the other to flush the hoses till clear and what was left into the evaporator again. Then I blew it all out with shop air.

The solvent is weird. I expected something like brake cleaner, but it's actually some sort of a citrusy smelling thing and doesn't feel corrosive or harsh. Got the gross old oil out pretty good, too.

I left all this stuff to dry overnight before reassembling the system. I suppose it would have been fine to just blow it out with air more, but I knocked off for the night anyway.

This is also where I drained shipping oil out of the compressor. It doesn't come out very well from the ports, and there is a drain bolt for this on the side. This bolt is also where you want to fill the compressor with oil, if you have a new one. Whole 8 ounces will go in there. Once you fill it, sit it with the pulley side down - this will lube up the shaft seal.

The reassembly starts with attaching the hoses to the compressor. New seals came from the AutoZone kit. The bolt calls for 24 ft-lbs. (33 Nm). This is one of those places where it pays to use a torque wrench, since you are compressing seals. While you are at it, replace the o-rings. Things will go much easier if you lube the rings with the PAG oil.

Then you slide this whole thing into place from above, but not all the way, just enough to have it sit there. Get underneath. Have the outboard rear bolt in the bracket. Slide the compressor back till you can start the bolt. You will likely be using an extension. Keep screwing it in and moving the compressor back. Stop when it's almost tight. Then got put in the three front bolts. They are 37 ft-lbs. It isn't really that critical, but I already had the torque wrench out.

Once the front bolts are snug, put in the other rear bolt and tighten them both. No way in hell you are getting a torque wrench back there, but also no way in hell will you be able to overtighten them.

While you are underneath reconnect the lower condenser hose.

Then go topside and reconnect the rest of the hoses. Remember to put the orifice tube in and to reinstall the pressure switch. Don't go all gorilla on the fittings, remember how much they took to get loose. And that this is aluminum.

Now comes time to evacuate. They tell you to pull a vacuum for 45 minutes, or something. I put the vac pump on and went to do stuff for a couple of hours. Too much vacuum ain't gonna hurt.

Then I shut the vacuum off and once again knocked off for the night.

In the morning I put the gauges back on and was pleased to find the system still had vacuum. That means we are good to fill.


This is where I once again hate the US Customary weights and measures.
The sticker underhood says I need 1.63 pounds of refrigerant. The can has 12 ounces. Two cans gets me 1 pound and 8 ounces. Which I now have to convert to decimal...

Fortunately, the sticker includes the conversion for more sane people and says I need 0.74 kg. And the cans are also marked in grams. So, .74 kg is 740 grams, and each can is 340, so two cans gets me 680, and I need 60 more. I used a regular home scale I have, put the can on it, and filled till the scale read 60 less

And then, this is done, and my AC blows cold.


This is what it cost:

Compressor kit $216
Condenser $119
Seal kit $9
Oil $9
AC Flush solvent $25
R134 refrigerant $27
Total $405

In retrospect, I probably should have gone for the $280 kit that had seals and a condenser. That would have saved me $64. Still, this is way less than a shop would charge. I am guessing this is probably at least a $1000-1200 job all said and done, if not more.

 

I also replaced my A/C system a few years ago. The most important part of the whole job was to vacuum out and hold it there for a few hours. The moisture in the system is what kills the ac.