Saturday, October 17, 2015

Air Conditioning

Let me begin this post by saying that it is for me. It's going to be painfully detailed and of import to nobody but me. You will be bored by technical details of something that doesn't really matter. I suggest you read no further.

On the other hand, if you can't resist an odyssey, then by all means, read on.

The purpose of this post is to chronicle the saga of the air conditioning system in my Land Cruiser. Over the last two years I've been putting money into the system a little at a time. At each step I thought that there was just some little thing to do to get the system back online. Each time I enjoyed AC for a short time, only to have another part of the system fail. So let's get started.

First some basics. Here is a diagram of my AC system. The major components are the compressor, condenser, drier, expansion valve, and evaporator. They are labeled on the diagram. The evaporator and expansion valve are behind the dashboard, everything else is in the engine bay. The refrigerant flows from the compressor to the condenser, through the drier, next the expansion valve, finally the evaporator, and back to the compressor.

Starting in the summer of 2013 I found that the AC wasn't making the air cold. At this point I didn't know jack about automotive AC, so I started the process of troubleshooting and figuring out what I needed to do. Soon I decided I needed to get this thing sorted out because I had to go to Utah in October 2013 to see my family and get some machinery.

The first step was to get it into a shop for some diagnostic. This is done by charging the system with a dye which shows brightly under UV light. It is very effective. The process of charging the system is relatively time consuming and requires special equipment, the two main contributors to expensive repairs.

9/4/13 $232
The first round of diagnostics. This determined that the shaft seal on the compressor was bad. 18 years was all it could take. This required replacement of the compressor. I also learned at this time that when the compressor is replaced you also need to replace the expansion valve and drier. The shop was kind enough to provide an estimate of $1125 for the repairs.

9/5/13 $285
I ordered all the stuff necessary to do this job. The compressor, drier, expansion valve, and other small parts. I was able to get all this stuff replaced on a Saturday, but I still had to take it back to the shop to get it charged and leak checked.

9/19/13 $204
This finished the initial repair. They charged the system and returned it to me. At this point I had saved $636. The system was online and I thought I was in the clear.

That feeling was relatively short lived. My trip to Utah had been cancelled, but the AC would have worked. A couple of months went by and I noticed that the air wasn't blowing cold anymore. As you might imagine, this was disappointing, but now it was winter so I decided not to act.

5/16/14 $42
I had the truck back in the shop for another diagnostic. For as little as they charged me, it seems more like a token charge than anything. Anyway, they found that the pipe between the compressor and the condenser was bad.

5/23/14 $438
I had them do this work because the savings would be relatively small to do it myself. They ended up changing the pipes on both sides of the compressor and recharging the system. Again, I figured I must surely be in the clear.

Again, this feeling was short lived. If you're keeping track, now I'm up to $1201.

And it still doesn't work.

Now we're into the summer of 2014 and this began a long period of procrastination. Fall of 2014 was extremely busy for us. I was busy at work and at home getting ready to go to Japan. Dealing with this was LOW on the priority, but it still bugged me. Of course, then we were in Japan, and it mattered even less.

This past summer in 2015, getting the AC working was a high priority for me. I wanted the functionality back because I hate it when the truck doesn't have full functionality. I figured the system had leaked dry again, and at its last charge it had dye in the system. The only part of the system that hadn't been leak checked was the inaccessible portion inside the dashboard, namely the evaporator and expansion valve. When I had removed the evaporator to replace the expansion valve in the first place, I cleaned a lot of dried leaves and crud off of it. I think this allowed some deterioration of the thing. So I pulled it again and looked it over with a UV light that I had bought. Sure enough it had dye all over it. Time to replace it.

6/18/15 $80
New evaporator core. The swap out is pretty straightforward. It had better be, anyway. This was the third time I took it out. Now the total is $1281.

By this point I was tire of taking my truck to the shop for AC charging. My buddy Ned is good at refrigeration and he has many of the necessary tools as well as a bulk container of R134a. After changing the evaporator I took it to Ned's for a charge.

The charge seemed to be going well. The engine was running nice, all the indicators were good, and we again seemed to be in the clear. Then we turned the engine off and noticed a loud hissing. We thought the joint at the top of the drier was leaking, but we wanted to put eyes on it. You have to take apart the grill and the headlight to get in there. When we got in there we discovered the pipe on the outlet side of the drier was leaking like crazy.

At least this is a good smoking gun. Proof positive that there is a problem and you know exactly what it is.

7/17/15 $154
New AC pipe and drier. Note that this is the second new drier. It was relatively easy to swap out. AC isn't really that hard, the trick is knowing the certain little details that will determine your success or failure. On the day I did this swap, I also borrowed Ned's tools to do the charge myself. There were two little snafus in this section of work. I'll go into those later.

The bottom line is I got the system running that day. The final total is now $1435, but it was working.

A friend at work said that it seems like I'm destined to never have AC in that truck. I sure showed her.

Until this last Thursday. October 15, 2015. I was out doing some errands when the engine suddenly began whining with a shriek I never knew a car could make and still otherwise run fine. It was the AC compressor clutch slipping. I later determined it was slipping because the compressor is seized. Compressors that are designed for gas are done in by compressing liquid. If they were for liquid we would call them pumps.

This is what I think happened. Oil level in the system is a critical attribute. Too little and you will burn up the compressor. Too much and you might seize the compressor. I'm pretty sure I had too much oil in it. The instructions that came with the drier said to put a small amount of carefully measured oil in it prior to assembly. I measured it with a syringe. As I was adding oil, it overflowed well below the specified amount. There was also a discrepancy between the Chilton manual and the pamphlet that came with the drier. I was going with the pamphlet because I figured it must be more accurate than the Chilton. When it overflowed I got confused and didn't know what else to do, so I dumped out about half of what I had added and proceeded with the installation. This was the first snafu. The second was that the system charged much faster than I thought it would. Before I knew it I was about 0.1 pounds over the charge specification. It's a small amount but could be enough.

While it was running during the last three months I noticed the expansion valve was very noisy. I don't know if that had anything to do with it. Maybe excess oil causes the flow dynamics to change which causes extra noise. I may never know.

So here I am. I have a broken AC system that has cost me $1435. If I was to allow myself further down the rabbit hole, the next step would be another $285 for a compressor, expansion valve, and drier. Having acquired the skills to charge it myself I would avoid more shop charges for that work. I hate to spend more on this broken system, but on the other hand, the other system components are now in great shape. By replacing the compressor and drier I would be able to start from a clean slate. I now know how to add the correct amount of refrigerant as well as the correct amount of oil. It's just one tiny step and I'll be back up and running for another 15 years.

It seems like I've heard that line before. Time to tap out.
And I thought the power steering story was expensive.


At 2:52 AM, Blogger Ambrose said...

My mother drives around without air conditioning in her little Saturn, and I simply can't understand how she deals with it during the summer time. While it may seem like a gigantic hassle, having a reliable air conditioner, especially on long road trips in hot climates, can make all the difference in the world, as you no doubt know!


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