AC recharge season is here - please be careful out there.

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Q451990
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So the Frontier developed a leak, and it got bad enough that it was only holding a charge for a month or two, so I decided to fix it. I got a loaner vacuum pump from AutoZone, some o-rings to replace the ones at the compressor that my leak sniffer said were leaking, and went to town. In my shadetree research online, I noticed someone suggest leaving your cans of 134a in the sun to help the gas expand and feed into the system more quickly. Not to be outdone, I decided that if sitting them in the sun was a good idea, heating up some water on the stove and letting the refrigerant take a hot bath before charging would be even better.

So yeah... near boiling water, and cans of 134a aren't the best combination. Luckily, I took the pot of water outside before I put the can in. I was also fortunate that my 8 year old son actually listened to me and didn't stand right next to the can. It exploded while I walked inside to get an oven mitt, and I didn't find the top of the can until several hours later when I noticed it about 50 feet away in the road.

So learn from my dumbassery... not only, don't heat up your can of refrigerant - but be safe in general. Wear safety glasses. Wear gloves. Pay attention to what you're doing. I discovered from this article that refrigerant is packed in cans that are only designed to hold up to 180 PSI. https://www.chemaxx.com/aerosol13d.htm This poor bastard lost an eye when he sat a can of refrigerant on his intake manifold.

My refrigerant at probably somewhere around 180 degrees was pushing 400 PSI! But even a normally charged system is over 200 PSI on the high side. So mess up and open the wrong valve on your manifold to "charge" the high side and you could have a bloody mess!


EdBwoy
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Thanks for sharing Q, that is a very profound reminder.

In addition to gloves, I like to insist on eye protection as well. I am lucky/ unlucky that I have to wear glasses all the time due to visual problems, but they have saved me from a lot of dust, debris, and even unidentified liquids dropping into my eyes.


There's no guarantee that even glasses would have protected the poor chap in the case study you linked... what that one reminds me of is the inadvertent danger we put ourselves in by such innocent actions.

my12by60
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Good reminder. I just changed out the evaporator and compressor on my wife's 1998 Dodge Durango. The compressor is a simple job, but the evaporator was a long project due to the location deep under the dash. I hope my Q does not decide to start losing its refrigerant.

98_Q45
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LOL....lets not give mechanics more reason to scold us for doing a/c work ourselves, (as one mechanic told me after 1 of my drier o-rings didn't seal after a replacement condenser/drier on my maxima last year). They want to talk us out of doing a/c work ourselves, but in the summer time, they know people need it, so they charge ridiculous prices. $50 a/c recharges are now $125-150.

My thing is, as long as the system is empty...its safe to DIMyself. I topped up my Maxima the other day as it seeed slightly low, but the clutch was still engaging. I only used a half 3 ounce can of oil/r134 to bring it up to 45 PSI. The way to "speed it up" is something I would watch my mechanic do years ago: grab the throttle cable and race the engine a little, maybe hold it steady at about 1,500 rpm. The compressor doesn't do much at idle, you have to get it going to feel cold air and suck in more "freon".

Right now my Q is still without A/C. If it weren't for the tinted windows and moonroof, I'd be baked. I'm shopping around for a/c compressors, and about to hit a junkyard to see if the 98 there has a pre-11/98 compressor I can use. It's brutal. There's been several times I walk out of the car and I almost collapse while I'm walking because a car is like a damn sauna here in Florida without a/c.

But yet, these f*** want me to pay $424 to register my vehicle. And I have no A/C. Pisses me the F off.

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Heath....of all people! Just ribbin' ya--- thanks for fessin' up and giving us all a good reminder. Curious what you used for a leak detector? I remember $1000 specialty electronic 'warblers' from 35 years ago when I worked in a garage. They probably have cheapo equivalents now.

I have found using the cans that the initial pressure is fine for the first 1/3 or so of the can. since it gets colder as the pressure releases I'll just shut off the low side manifold valve when I see the needle drop to the low side pressure level (stop at about 2 psi above just to prevent backwash).
I personally think judicious warming of the can is fine after the first 1/3 is bled off. I have used a pot of hot (130F-ish) water as well as putting it in the engine side radiator fan flow to warm it in between fill pulses.
Also, there is no 'right-side-up' concern with R-134a (as opposed to R-410A--which must be fed with the bottle port inverted).

Be safe everybody :cheers:

98_Q45
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Does anyone have any tips on removing the a/c compressor on 97-99? I found a salvage yard that seemed to have an equivalent one that mine uses, but it seems there's only 2 bolts that are accessible.

I'm not going to even mess with the salvage yard compressor even though it seems like it still had a little bit of refrigerant left. Too much risk of having something go wrong down the line. Plus, each time I come across a q45 in the junk yard, it's caked from oil leaks... So I rather just buy a new compressor, but I can't seem to figure out how to get started on it. Seems like it must only be accessible to remove from the bottom

amc49
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You can slightly heat the refrigerant can but like said above, no more than 130 degrees. I do less. The can if up to full has about 75 psi in it at room temperature. I knew someone who pumped refrigerant into the highside back in the '60s and he lost 3 fingers on one hand when the can exploded. Why the recharging kits only do the lowside and the fitting cannot work on high. Liability issues.

The problem of course is that it is incompetent to charge using lowside only as the highside is what determines when you are at the optimum charging stop point. There is a whole slew of problems that show immediately on the highside but do not on lowside as well.

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elwesso
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Yikes! R134a compared to many other refrigerants is medium pressure too!

I always just used hot tap water, low side pressure on the system is only about 40 PSI, so as long as it's warm to the touch it's gonna go in.

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HansCC
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Big WOW - thanks for sharing - I follow Youtube but you got the guy that suggested SS - my upper mgr uses this all the time - don't do SOMETHING STUPID - I too could make cans fly -

sheikhnbake
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Wow, all that sounds like an awful lot of time and trouble to fix an a/c leak. I guess I'd ask myself, how much is my time worth, and what does an Infiniti dealer charge? Unless fixing cars is a passionate hobby of mine.


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