Monday, May 27, 2013

Time to fix the AC!

When  I bought the truck, the AC worked great, which I thought was awesome. When I got it back from the shop, the AC still worked. But weeks later, it died, quickly. That indicated a massive leak, not something simple. Rather than take it back to the shop and not know if it was done right, I decided to fix it myself. I'd done AC one time before with a friend who did things like that for a living, so I had a hands-on overview. And, I have to say, YouTube sure helps make it easier.

It took very little time to find that the condensor had a hole in it from a bolt in the grille. Someone leaned against it and it worked its way in over time. The solid motor mounts didn't help, I'm sure.

AC parts have come down tremendously and I was able to order a replacement condenser. At the same time, I decided to convert it to R134A since R12 has become so hard to get and I want to be able to self-service the system in the future.

Skeptically, I used the Harbor Freight compressor-driven vacuum pump and their AC manifold. It leverages the venturi effect to create a vacuum. It worked quickly and pulled a pretty decent vacuum, I must say.

Since I didn't take pics, I'll leave the installation part to some google searches. :) However, I feel it is very important to call out a very neat feature Toyota included in their AC setup - the ability to easily change the RPM at which the compressor kicks on.

After doing the install and conversion, the AC worked GREAT - underway. At stoplights, the compressor kicked off and the dash was quickly pumping outside air into the cab, bringing in heat and any humidity. Yech!

Behind the glovebox (snap down the vinyl), there's a little black or green (mine) box with a knurled aluminum knob poking out the top. Wish I had a picture for you. Warm the truck up fully and put it in Drive if it's an automatic (have someone standing on the brake so you don't get run over) or idle in Neutral if not, turn the headlights and any other power-hungry electrics on so the system is fully loaded, and turn the knob (can't remember the direction, was months ago) until the compressor kicks on. Then about 1/8 turn more just to be safe. NOTE: This assumes the idle VSV is working as expected.

R134 is inherently less efficient than R12, so long periods of idling will mean the AC isn't quite as cold, but once underway, it's quite good. It gets expensive trying to improve this, so you'll have to chalk it up to Treading Lightly on the environment resulting in reduced AC performance. While you could turn the idle up, there are lots of reasons that's not a good solution.

Another issue was that the AC would intermittently stop working. Nothing I'd changed would cause this. We were in Houston after a hurricane in 95+ degree super-humid heat when we found out this tidbit. Man oh man, was that uncomfortable!!

While adjusting the AC amplifier, I found a connector had hooked itself onto the glovebox light switch bracket and was intermittently shorting out. That must have been it, as it's been months and the AC works as expected. Thank goodness, I wasn't looking forward to trying to change some of the sensors under the dash!!

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