PO disconnected the AC hoses

Hmmm....I'm finding myself becoming a personal "home shop" AC repairs expert - on my own cars. I already scored a NOS recovery machine ($200) with built in vac pump, manifold gauges, a 30 lb recovery tank (134a), assorted hoses and fittings. This micro vac meter might be a good "tool" to have in my stash. I'm fine with "used" (aka ebay and Craigslist). Any brand recommendations to consider as better items?

Bob R.

 

LOL....reluctant ac tech- I found the same happened to me! But I confess I was more eager than reluctant, as I find this subject very interesting (I know, signs of a lunatic).

To me the idea that we can cool our cars with the simplest of organic compounds like propane is real cool. No need for the factory industrially synthesized multiply halogenated compounds that are toxic, ozone destroyers, and corrosive, expensive, and sometimes not even available.

1) Heres duracools instructions on evacuating- not what you might have thought-


CHARGING PROCEDURE

Recover any existing refrigerant charge into a suitable container, regulations vary by region and the recovery of existing refrigerant may need to be completed by an authorized technician. Leak test the system, if a leak is detected the system must be repaired prior to charging. DURACOOL 12a® is flammable and should only be leak tested with an electronic hydrocarbon leak tester, soap bubbles or fluorescent tracer fluid. If leaks are detected, ventilate the area, keep away from flames and repair the leak. After repair, continue with the charging procedure. Pull a vacuum of at least 25 cm Hg (10 in Hg). If a vacuum pump is not available be sure to use Duracool® DuraDry™ to remove system moisture.


Soooo, you see, guys, no need to pull a vac to 29++ ' Hg. I have spent much time on the phone , personally, with the chief tech guys at Duracool, as well as ES Refrigerants. ES actually does not recomend a vac at all. Some of this info is not even on their sits! You see, this HC alternatives business has a shroud of secrecy/vagueness to it. It cus in part, EPA has ostraized them as outcasts cuz they dont ascribe to the mainstream DuPont /Congress lobbyist auto ac refrigerant cult.

 

No problem, Mike. I am familiar with these reactions- Water can not react with the simple alkane - propane cuz there are no highly reactive atoms on the molecule, like Fluorine and Chlorine. Thats why a tiny amount of moisture is no big deal with HC refrigerants. Also, Your idea that water takes up space is not realistic as water (most liquids) can not expand much more that their volume at ambient temperatures or even at higher temps like gasses. Nothing no way near it. So the volume that water takes up in the ac system is insignificant.

If as you say, the system pressure will be too high, its cuz you have too much gas, NOT WATER in the system.

 

PAP might be more familiar with HC's since he lives in Australia, a country very friendly to HC's! Lucky stiff.

But, Pap, I agree that moisture is not a friend, but it corrodes no more than it does in a crankcase- moisture gets in there, and purged out occasionally with a hot engine, but it comes back again, and again, and again. Does that corrode your crankcase? Doubt it.

remember, ac dryers , contain silica, which can absorb at least 6 grams of water, even up to 10-12 g of H2O. Thats why we have dryers in our ac systems. Dont worry, be happy.

You have to evac to 28-29" Hg for R12 or R134a (this is standard procedure in at least one GM shop manual I have seen, although, even better to get to 29.5+). Get the H2O out as much as possible as it will react with the halogens to produce deadly corrosive Hydrofluoric/Hydrochloric acids. And that, the dryer can not absorb............

 

You have to remember mate, if you remove moisture properly (vac down a/c system), rarely moisture every re-enters the a/c system.

And if it does, the drier "catches" it. Yes, correct. As soon as the system is open to atmosphere, moisture gets in there.

We remove compressors at work almost daily and sometimes we open them up if we're bored and some are very coroded from not being vacced down properly.........or at all.

In the underground mining enviroment, a/c hoses blow constantly. 99% of the time, the hose gets changed on the job, a/c filled up and the a/c system never gets vacced down. So when the compressor is finally changed out due to failure to preventative maintenance, the internals are very coroded.

I should have been more clear in my post as we are talking cars here, but the fact remains that moisture does corode a/c alloy internals over time if the system has been open to atmosphere and/or has never had the drier replaced.

If you follow correct a/c service and repair procedures you should get a lifetime out of the a/c compressor.

 

Real good point, Pap. Thats where an experience like yours is very helpful. You know, I wish things could last almost forever- I still have been perplexed as to why most of these propane suppliers dont insist on vac down to 29++. (shrug). leave it to say that moisture with freon is waaaaaay worse than with straight chain HC, no question....

take care, pap.

 

All good info which brings to mind my question. If anyone has real world ,hands on experience with changing to a rotary compressor I would be interested in hearing from that person. I am on the fence on rebuilding the original or redesigning the system. We live in the far north and AC is not needed very often but after the 90F+ heat at RA last weekend we decided to reconsider. The AC didn't work when we purchased the car and it really didn't bother us but most ,if not all, events are way south of us. Lost

To be sure if anyone has done this conversion was the differential worth the investment?

 

The propane substitution is interesting.

If someone was to do this is one potentially driving around with a bomb in the dash? I'd have to declare my car a "non smoking" area maybe?

cheers

 

Not anywhere near as hazardous as that fuel you are carrying around...

 

While that's true, I don't have a fuel tank "inside the car" connected to something in harms way out in front of the car. Don't want to convert my car into an old Pinto ... spontaneous combustion upon impact .

cheers

 

Yeah, interesting question thats for sure.

Cheers mate, take care and have a GREAT weekend my friend.