rwh2toyota

I have a 2000 V6 4Runner and my A/C felt a little warmer than it had been in the past, so I charged it with an over the counter R134a kit from walmart. I followed the instructions and everything seemed fine, but when I ran it shortly after charging an awful burning smell came out of the vents and i saw smoke under the hood and now it just blows hot air. It appears there is a rubber gasket or something around the compressor clutch that has burned up and melted and now the compressor barely turns when engaged. I'm pretty sure I overcharged the system which led to whatever failure I experienced, but it still holds pressure now after I vented off some of the refrigerant. Rather than mess with what I think is a destroyed clutch, I'm just going to replace the compressor/clutch with a used one. My question is, hypothetically, could I evacuate the system by just venting the low side into the atmosphere and then hooking up a vacuum pump once the pressure was equalized with the outside air? Is there anything else that I would need to do before changing the compressor out to make sure nothing explodes in my face? I assume I would need to vacuum again before adding refrigerant after the repair to make sure no moisture got in.

I just can't see paying a shop 50 bucks to suck out refrigerant if I can do it myself. Any help or advice is greatly appreciated.

fierohink

In today's world there is a lot wrong with the idea of just venting to the atmosphere older refrigerants. They are greenhouse gases, they are poisonous to breathe, and they can cause burns to exposed skin.

You see recovery at a $50 expense a waste.

You can replace the compressor with a used one and hope for the best. You won't know how much oil is in your system which will likely lead to premature failure of your new-to-you compressor. Chances are you blew the seal in your original compressor because you used a wally-world kit and didn't hang a set of a/c gauges to know what your high side vs. low side pressures were.

And to go with your statement of:
isn't exactly accurate because they would be recovering it which you would not. And if they were a competent shop would probably also be adding a UV dye and checking to make sure your system is tight and healthy.

Again, are you hanging a set of A/C gauges when you do your vac down?

mwisham

Ditto what fierohink said. You probably overcharged the system and caused the clutch failure. You should be able to buy a new aftermarket compressor/clutch assembly for around $300. You should replace the receiver/filter/drier while you are at it. I would never ever put a used A/c component of any kind on any of my vehicles. Go ahead and spend the money to put new parts on, you'll be glad you did. Get a competent A/C shop to recover the refrigerant, swap out the comp/clutch assembly then take it back to the shop to have a good hard vacuum of at least 45 minutes put on it then recharge with the correct amount of refrigerant and oil.

rwh2toyota

The plan is to hang gauges when I vac the system myself. After installing the new compressor I'll vac the system again. Setting aside our philosophical differences about what to do to properly evacuate the system, how do I add oil to the system after the post installation evac? Sort of thought that had to be poured into the compressor before installation.

Outsane

Some compressors come pre filled

fierohink

Like Outsane said, some come pre-filled, some don't. If you are buying used, you can rest assured that thing has rolled around a bit and doesn't have all the oil it's supposed to.

Working on A/C sucks for a novice. There are a lot of parts that can go wrong. Like Mwisham said, change out your filter/drier orifice. It will save you some headache.

Read up on what to look for going through the sight glass. I think on a '00 it in along the upper rad support. (Can't remember it's been a while since I did a/c on a '00) Read about what the gauges are telling you. It isn't an exact psi you are looking for as more a comparison between high and low sides, needle movement, etc.

Good hvac guys make it look easy through skill and knowledge, not because the task is simple.

mwisham

If you have a way to properly vacuum system, great. There really is no need to vacuum the system prior to replacing the compressor. The main purpose of vacuuming the system is to lower the boiling point of water to below ambient temperature in order to remove any water vapor present in the system and also remove any air.
They make small cans of oil charge that you can use through the guages and a can tap just like cans of refrigerant. Just make sure it is the correct oil for your system.

rwh2toyota

Thanks all. Doing it tonight. This ought to be interesting. Will let you know.

mwisham

Please let us know how everything turns out.

yamaha73

Like few said before I would probably change your orifice and dryer because if the compressor failed it could have thrown debris through the line and junked your dryer. I've had it happen many times (well on cat equipment)

DailyDrive

You overcharged the system. There was too much refrigerant on the way out, so it didn't turn into gaseous form before going back into the compressor. So refrigerant in liquid form hit the compressor. You basically hydro-locked the compressor, destroying the clutch or compressor internals, or both.

Cut your losses and have a professional repair it. Based on what you did already, it's very unlikely you'll be able to fix it long term on the first try. Probably not even 3rd try. It's not a tire rotation.

sharrack

Repairing an AC system is an all or do it again process. If your compressor went dead, it has contaminated most other parts of the system. Receiver dryer, any inline filters and the compressor itself. Aftermarket parts (IMO) have become a luck o' the draw purchase these days. I've seen people go through 3 compressors before getting one that lasts longer than a week.
Do your research, choose wisely and only do it once.
Cutting corners with AC systems will have you doing it all over.

DRCOFFEE

Go ahead a vent to atmosphere. Your measly 22 ounces is nothing compared to the ruitine industrial leaks and oops that happen every day. We are made to feel like criminals for venting miniscule amounts of chemicals in our infrequent DIYs yet BP can dump millions of gallons of petroleum into the gulf of mexico and lake michigan and we are all still alive to talk about it. Any hoo. Dont sweat it.

I used these videos to help do my kids ac system. Covers most of what you can expect. Buy a set of manifold gauges from harbor freight for $45. Hopefully you found this post more helpful than the obligatory "you are too stupid to work on your own AC" reply above. Its detail oriented work, but not rocket science. Evidence all the high school drop outs now doing HVAC for a living.

DRCOFFEE

Spoken like an internet expert. The 3rd gens have an expansion valve, not an orifice tube.