YACT - DIY A/C recharge?

[Slickone]

Stores now have available the all in one R134A can with the disposable hose and gauge built it. How safe is it to do this myself? As long as you connect it to the correct fitting, there's not much danger of an explosion and/or doing damage, is there? It'll only take in as much as it can/needs to, right? I need to do my g/f's '94 Volvo. Someone else used one of these in the past to recharge it, but I've never recharged one myself (have done a decent amount of other mechanic work though).

 

[Slickone]

^

 

[nakedfrog]

Also curious.

 

[iamwiz82]

Are you sure that car takes R-134 and not R-12?

 

[djheater]

What people said when I asked.

Basically, it's not worth it.... AC is a closed system, so the fact you need a recharge indicates a leak.
Unless you're willing to get in there and fix that, you might as well take it in.

 

[Zenmervolt]

Originally posted by: Slickone
It'll only take in as much as it can/needs to, right?

Wrong. It's easy to over-charge an A/C system and overcharging it is bad. Though as long as you watch the guage, you should be able to easily avoid overcharging.

However, an A/C system does not normally lose refrigerant. If the car has lost refrigerant, it's leaking from somewhere and you'll need to fix the leak or else you will need to re-fill it all the time.

Also, 1994 was about the time of the switchover from R-12 to R-134a. You CANNOT mix the two types, so before you recharge the system you need to make sure that the car uses R-134a. It probably does, but you need to check that before adding R-134a to the system.

ZV

 

[dabuddha]

It's very easy to do. I did it myself on my honda accord whenever it needed and had no problems.

 

[Slickone]

Originally posted by: Zenmervolt

Originally posted by: Slickone
It'll only take in as much as it can/needs to, right?

Wrong. It's easy to over-charge an A/C system and overcharging it is bad. Though as long as you watch the guage, you should be able to easily avoid overcharging.

However, an A/C system does not normally lose refrigerant. If the car has lost refrigerant, it's leaking from somewhere and you'll need to fix the leak or else you will need to re-fill it all the time.

Also, 1994 was about the time of the switchover from R-12 to R-134a. You CANNOT mix the two types, so before you recharge the system you need to make sure that the car uses R-134a. It probably does, but you need to check that before adding R-134a to the system.

ZV

This car does use 134a. I seemed to remember many switched in the early(er) 90's. My '94 Toyota pickup was 134a also. You can use 134a in most R-12 systems if you evac it all first. Many don't require any component changes. A friend's shop did my '87 300ZX that way. Just had to replace the hose fittings or use adapters (can't remember).

I realize the system needs to checked/fixed for a leak (I told many people that as a service advisor years ago), but she will be selling the car as soon as she finds something else to replace it.

The only thing is finding out what PSI the system on that particular car should be charged to since they're all pretty varied. Does the CD that comes with some of the kits tell this for each car? Don't have a Haynes for this car.
Also id makes so many different kits, it's a bit overwhelming deciding which to buy.

 

[jtvang125]

I did the R-12 to R-134 conversion on my previous car by myself. Had my friend evac and refill the system. It wasn't as cold as before but better than no a/c at all.

 

[Zenmervolt]

Originally posted by: Slickone
This car does use 134a. I seemed to remember many switched in the early(er) 90's. My '94 Toyota pickup was 134a also. You can use 134a in most R-12 systems if you evac it all first. Many don't require any component changes. A friend's shop did my '87 300ZX that way. Just had to replace the hose fittings or use adapters (can't remember).

I realize the system needs to checked/fixed for a leak (I told many people that as a service advisor years ago), but she will be selling the car as soon as she finds something else to replace it.

The only thing is finding out what PSI the system on that particular car should be charged to since they're all pretty varied. Does the CD that comes with some of the kits tell this for each car? Don't have a Haynes for this car.
Also id makes so many different kits, it's a bit overwhelming deciding which to buy.

Pretty much generally correct.

R-134a cannot carry the lubricant used in R-12 and if the lubricant used with R-134a is mixed with R-12 lubricant, they will combine to form an acidic sludge, that's why you will need to evacuate the system. Note that this means you will need to also replace the lubricating oil.

The pressure shouldn't vary much from car to car. There's enough leeway that a generic range will be fine. At 90 degrees ambient you're looking at 25-30 PSI on the low side of the system at idle. At 75-80 degrees figure on 25-27 PSI on the low side at idle. This should drop by 2-3 PSI at 1,500 RPM.

ZV

 

[OrganizedChaos]

1) evacuate system to 25 microns.
2)wait 10 min or so to make sure system isn't leaking.
3)recharge to factory specs with a charging scale.

 

[xanis]

I'm curious about this myself. I bought a can o Castrol R-134a with leak-stop for $25. I think it's worth a shot considering all of the shops/dealers around here want $140 to diagnose and recharge my system.

 

[Pacfanweb]

Yes, it's easy. You connect the hose to the low (suction) side of the system, and charge it. Easy to tell which side is the low side....the high side goes to the condenser in front of the radiator.

If you have a slow leak, you can charge it up and it might last you a year or more, until you decide to fix it.

If it doesn't even last a week, you need repairs before wasting any more refrigerant.

My truck needs a manifold line, and has for the last 3 years. I charge it in the spring when it first gets hot, and it lasts until I don't need the A/C in the late fall.

A professional, like me, speaking in a professional capacity, should tell you that you should get it fixed before charging. In my non-professional capacity, follow my former advice.

 

[Pacfanweb]

Originally posted by: Xanis
I'm curious about this myself. I bought a can o Castrol R-134a with leak-stop for $25. I think it's worth a shot considering all of the shops/dealers around here want $140 to diagnose and recharge my system.

Haven't used that stuff, and I'm a little leery of anything that says "Leak Stop" with regards to A/C systems. There's a whole lot more pressure in an A/C system than there is in say, a cooling system.

 

[Rogodin2]

If you're low on freon then you have a leak.

The problem with recharge kits is that you can foul the expansion valve.

If you really want to do it yourself you'll need to disconnect the bees and pull a vacuum. Once the bees are evaporated and you do a leakdown you can fix your leak and pull a vacuum again.

Rogo

 

[djheater]

I just took my not cold blowing car to Firestone for repair.

I'll let you know how much they rape me for.