DIY Vehicle A/C Recharge

[SamC.]

Pelican Crew, the A/C in my 2001 Suburban is noticeably warmer /less cool this summer season. That's not surprising given the last recharge of freon was 6 years ago. I am considering doing this as a DIY project as opposed to going a local shop or dealership.

As I have no experience with DIY refrigerant recharge, I would appreciate some input on this. Do I tackle this with a AutoZone kit or bite the bullet and let the professionals do it? Thanks for the assist!

Sam

[Scott Douglas]

I wouldn't waste my time and let the pro's do it. Unless you can pump down the system to see if it'll hold vacuum you're spinning your wheels.
My wife complained that her car wasn't getting cold like when new a couple years ago. Found a guy with a sale on re-charging/checking the system for $49. He had a Snap-On device that evacuated the system, pumped it down, checked for leaks and refilled that was pretty slick and non-polluting too. Car blows ice cold to this day. It is a 2013 model that had never had the system checked out before. No leaks, it just needed a refresh.

[1990C4S]

Top up or evacuate and start over?

For top up I recommend buying a set of gauges, then going online to watch YouTube video. I learned a lot from there.

Evacuation? Others will chime in, you need a good vacuum pump, and they aren't cheap. You are also 'supposed' to recover the refridgerant.

[GH85Carrera]

It depends.

Are you interested in learning a new skill, and learning something new and buying more tools? Will you be doing more than that one car?

To do anything much at all to an AC system you really need a set of gauges. A good set of gauges, and the hoses is step one. A cheap low level set of gauges is going to be 40 bucks, a good set is 100 bucks, and you will need a vacuum pump as a minimum. A used recovery system is a really nice thing to have.

Many times it is just a low refrigerant charge, but certainly not always. The entire system needs a pressure check, what are the high pressures, what are the low pressures when running. On my El Camino the orifice tube is often the culprit from a clog of gunk after 6 or 7 years. A $2 orifice tube replacement required recovery of the old refrigerant, open the system, and I always replace the receiver-dryer as a matter of course, and the orifice tube. Then recharge.

There are different types of AC systems, so you will need to learn about that system and how it works.

AC work is pretty easy, just a lot to learn, and proper procedures to avoid releasing refrigerant to the air or overcharging you system and causing a total system failure of the compressor.

[JackDidley]

Its a 20 year old vehicle, I would not spend big money on it. This guy makes adding 134a very simple.

[cabmandone]

First, since you said it's not as cool I'm assuming it's working just not as well as it should be.
Now, go to autozone, get a can of 134 that has the low side fitting on it. Put it on the low side and open the can with the can right side up (I mention right side up because if you invert the can, you will be liquid charging which isn't something a novice should be doing) As the system draws the vapor off of the can, you'll need to have some hot water to put the can in. The hot water will boil off the liquid and build pressure in the can which will allow more vapor to be pushed into the system. You want to add refrigerant until you see the suction line starting to develop condensation "sweat" on it. As you're adding vapor it's also good to have a thermometer in the vent to check vent temps. As a rule you want to be 25-30 degrees below ambient outdoor temp. If you've got condensation and you're in the temperature differential range call it good.

Note: You can over charge but it's pretty easy to tell when that happens. When you add refrigerant your vent temps will actually increase rather than decrease.

Remember: You're looking for condensation to build on the suction side which is the larger line. The liquid line will be hot to the touch as the system is running.

It's nice to have gauges on the system to see what the high side is doing but again if you look for sweat on the suction line it's typically running "okay".

[Rusty Heap]

good chance you have a leak somewhere, freon just doesn't "go away". take it to the professionals.

[flipper35]

I did DIY for the truck, but my BiL had the vacuum pump and I had to replace the compressor so there was no refrigerant in the system to begin with.

If yours is just low, I would take it in somewhere.

[fastfredracing]

Im in the if it works , but just not ice cold, toss in a can , and you may get through the season camp. If it gets warm quick, then you need a professional able to dye , check for leaks, repair leaks, evacuate , and properly recharge .
Just put in regular r 134. Don't buy anything fancy with stop leak, or reconditioner . Dye is o.k, maybe even preferred .
Its not rocket appliances .

[Zeke]

I do my own and I dread every minute. Right now I have 3 out 3 vehicles that have zero AC due to leaks. What sours me is I paid 2000 dollars to a well known Porsche shop that Wayne uses to replace the evaporator in the Boxster. The entire dash and steering wheel had to come out and then codes rest. Lasted one year. I added a can and it barely was enough to get the switch on the dryer to come on. Leaked out overnight. I won't go through the trouble on the Boxster if the leak isn't an easy one. Too hard to work on.

The other 2 I'm getting ready to put the dye in as it's 90º here today. I hope I find the leaks easily. I have the vacuum, good gauges and plenty of r134a. If I can't do it I'm selling the cars as is.

Most AC guys are hacks. $2000, eh??? Makes more sense to put the money towards another used car. I'm not talking about my '06 Chey PU here. That I can suffer through regardless.

If you do take your car in, take it to a shop that does nothing but AC, not someone who is changing drive axle boots in the morning and posing as an AC tech in the afternoon.

BTDT.

Some of these idiots don't know to lube the seals with compressor oil while assembling. You just waste your money on a fool like that.

The point is, if I can do it, then anyone can do it haphazardly. I'm not properly trained. That doesn't mean I don't get lucky sometimes.

BTW, I do the house AC as well with R410a. I'm not trained for that either as I don't fully understand 'super cool'. You really need to know that one.

Edit: Wayne Dempsey messaged me asking which shop. I told him of a shop in Torrance and he told me he hasn't used them in over 10 years for similar reasons.

[asphaltgambler]

Originally Posted by GH85Carrera

It depends.

Are you interested in learning a new skill, and learning something new and buying more tools? Will you be doing more than that one car?

To do anything much at all to an AC system you really need a set of gauges. A good set of gauges, and the hoses is step one. A cheap low level set of gauges is going to be 40 bucks, a good set is 100 bucks, and you will need a vacuum pump as a minimum. A used recovery system is a really nice thing to have.

Many times it is just a low refrigerant charge, but certainly not always. The entire system needs a pressure check, what are the high pressures, what are the low pressures when running. On my El Camino the orifice tube is often the culprit from a clog of gunk after 6 or 7 years. A $2 orifice tube replacement required recovery of the old refrigerant, open the system, and I always replace the receiver-dryer as a matter of course, and the orifice tube. Then recharge.

There are different types of AC systems, so you will need to learn about that system and how it works.

AC work is pretty easy, just a lot to learn, and proper procedures to avoid releasing refrigerant to the air or overcharging you system and causing a total system failure of the compressor.

^^^^Excellent reply^^^^^^

[mattdavis11]

High side service port on those vehicles is the worst design I've ever seen. One time use. There's a a little rubber ball looking thing that will leak. Look under that cap for oily residue, if leaking, you will need to replace it. There is a tradition style shraeder valve replacement. Local flaps should have them. Vacuum and recharge.

I don't let anyone near my a/c systems, never know what residuals there are in their gauges/machine. I like doing a/c work, easy peasy

[Brian 162]

The only thing that I will add is to wear safety glasses and gloves. The refrigerant is very cold and can give you frostbite if things go sideways.

[WPOZZZ]

I filled my 88 cab by myself. Got the hose with gauge along wit a can of r134. I did this on a whim as I already had the hose and can from when I used to top off my 91 turbo. Plug the hoe into the ac connector, cranked the engine, turn on ac to high. Squeeze the trigger and watch the pressure. Voila! I had working ac in the 88!

[RANDY P]

Originally Posted by WPOZZZ

I filled my 88 cab by myself. Got the hose with gauge along wit a can of r134. I did this on a whim as I already had the hose and can from when I used to top off my 91 turbo. Plug the hoe into the ac connector, cranked the engine, turn on ac to high. Squeeze the trigger and watch the pressure. Voila! I had working ac in the 88!

( EDIT: I thought you meant 88 Chev.)- anyhow:

The A4 compressor is a worthless POS. in the 10 years and 50K miles I've had my truck I've swapped it 3x. There are no good variations.

This is what I ultimately wound up doing- a full Sanden conversion end-to-end (parallel condenser, elec. aux fan and 7 blade late model fan. Wasn't cheap but now I don't have to worry about it coming apart every 24 months, and contaminating my system with metal shavings.

Cold as hell, reliable and quiet now.

[mattdavis11]

^^^ They had R4 compressors, and good ones can be found. Stay away from ones that are 4 Seasons/Murray. They have used the wrong size yoke? yolk? in them for a long time and they will rattle even right out of the box. I've seen some that have vibrated so much that the metal high and low lines (manifold hose assembly) at the back of the compressor crack and break.

That's a nice set up that you have there Randy!

[Baz]

Yo Sam......you can add some refrigerant yourself. I have done so for my '02 Silverado, which is similar to your 'burb.

There are a bunch of videos on YT that show you how to do this, along with bits and pieces of other info on your system. Worth watching just to develop your knowledge base.

This video goes through the basics although it's not your vehicle. I get my refrigerant from Walmart. They have an assortment of products, including the lubricant which is also helpful to add.

I've also had a worn o-ring at my switch that I had to replace. Something else to consider if it doesn't stay cold after adding the refrigerant.

[Baz]

I ended up replacing my switch as well because it was faulty.

[Baz]

$25 at Walmart:

[aschen]

for a mild top off, you cant really rely on pressures once they are close. I find a cheapo thermometer in the vent is help for these approximate refills. IF the vent temp is coming down while adding refrigerant its a good sign.

I have done alot of AC work in the last few years. Living in houston and liking crappy cars has made it a bit of a requirement. I have gotten by pretty well with a 99$ vacuum bump and 40$ service gauge set from HF. You don't need super fancy stuff for most jobs i have found.

My lawyer has advised me not to talk about my reclaim procedure though. The spray air duster you use to clean keyboards and the like is often R134A.