Cab A/C Service

[Rokrover]

Just had the under hood A/C system purged and recharged with R134a plus oil as it was becoming less efficient with the compressor cycling repeatedly. The last recharge held up for 3 years and we need reliable air in the cab now the rooftop A/C is history.

The shop tried to pressure me into a new (rebuilt) compressor claiming the original was leaking excessively. The tech claimed to have detected fluorescent dye stains with a UV light but I had already done this check myself to confirm there was no hint of a refrigerant leak. Thus I was able to resist advice to toss endless wads of cash into the rig when a basic recharge will last several years.

Some folks let their RV’s sit idle a whole season or more. In that case it’s sensible preventive maintenance to idle the engine with A/C on for 5~10 minutes every couple of weeks during storage to circulate compressor oil around. Otherwise seals will eventually dry out, especially in our older vehicles, and leak at startup. Then shops will certainly try to pass on the major expense of a rebuilt system AND conversion to handle more environmentally friendly refrigerants.

[Blue~Go]

It's so important to have knowledge, isn't it? Geez.

Since it's on topic, and may help someone, I'll tell my cab A/C story.

It worked perfectly from when I bought the rig (early 2014) until summer of 2016. Then it did that thing where you get this "did this used to be colder or am I imagining things?" feeling, which then turns into, "no, okay, now it's totally warm."

Brought it into my neighborhood trustworthy A/C shop (yay for that), and they re-filled it with refrigerant, added dye, and I think they recommended a new ... can't remember what... receiver/dryer? Something that was recommended due to them evacuating the system, IIRC. At any rate that was all about $135 so no complaints from me.

But then a month or two later (August, naturally), it got warm again. I looked around with a light at night and found dye up near the upper left (I can't believe I'm forgetting all these names, but it was just ahead of the dash on the passenger side under the hood). Brought it in and showed it to them but we/they still had a hard time finding a leak. They persisted, with pressure tests and etc. Eventually they pulled out a little green rubber o-ring/washer dealie that had a tiny, tiny, TINY groove in one spot. We couldn't find anything else that was leaking so they cleaned the area, put in a new one, re-filled, and away I went, somewhat dubiously. I would have preferred some big ugly obvious leak.

But now it's two years later and it's still working. Kudos to them for finding it (they probably could easily have talked me into a new compressor or something at that point).

[chin_k]

honest mechanics and knowledgeable customers are the reason our economy is not doing better.

This reminds me that I should take the Chinook out for a spin every once a while. It has been idle since March, and maybe I will go to someplace nice and hot, like Arizona to give the ACs a good exercise!

[Blue~Go]

I know you're just joking, but I think it's the opposite: With a good/honest mechanic, I'm more likely to take my Chinook in and let them fix it, plus I'll tell others about how great they are. Lousy ones I won't go to (I'll do it myself if it's in any way possible), and I'll let people know I had a bad experience.

In most cases it's not that I *want* to work on my vehicle - it's really just that I want to avoid a horrible experience or bad work.

[Astrodokk]

Mine is a daily driver, and believe it or not, I actually turn on the AC even when it's cold to exercise it.
My Jeep turns the AC on automatically every time I turn on the defrost. Sure don't know why it does that but hey, I leave it about 5 minutes to get it's exercise too!

[chin_k]

AC works like a dehumidifier, so if you have the mode on defrost/windshield, the AC will be on.

[Astrodokk]

Wow, cool, literally!
I did not know that. So is it best to leave it on during the whole time defrost is on? I kind of like the heat and to feel the cold when I don't want it was weird.

[chin_k]

AC + heat = dehumidifier.

If the AC continue to run when it reach the temperature, you can keep the cabin temperature nice and toasty. However, I think most cars disengage the AC compressor when the temperature is lower than the setting, so you need to keep it on defrost/windshield for the AC to run. If you keep the defrost on for no reason, it is going to affect your MPG.

[Astrodokk]

Hmmm, I didn't know that. I like my defrost on when I start her up in the mornings. Talking about my Jeep now, since it starts the AC automatically with defrost. I usually turn the AC off when that happens.
Then, I keep the defrost on the whole day just so the windshield doesn't fog or just bc I like the feeling of the heat but not on my face with the dash vents.
I guess I'll stop doing that or leave the AC on with it.
The Chinook has the MIX feature on it but the AC doesn't come on automatically, since it's manual controls as you know.