How to tell if A/C refrigerant is low? Steps to recharge?

Is there a way to tell if the A/C needs a refrigerant recharge (other than the air not being a cool as it once was). My 05 Tacoma has never had the A/C refrigerant (R134?) recharged so I'd like to top it off but want to be sure there is not way to overfill. Also, I'd appreciate it if someone would provide the basic steps. I has been about 15 years since I recharged an A/C unit. I will also be doing the same for my wife's and daughter's Highlanders. Thanks!

 

Get a set of gauges. That's the only sure way to find out what's going on.
I would take it in for a service. Without a leak test, you'd waste money on refrigerant (if it was leaking). Yes, you can over-charge it. Capacities are listed on the tag in the engine bay. When they put a vacuum on the system, they can see how much was in there, if it leaks, and put in the right amount. Doing it any other way is guessing.
Do not vent to the atmosphere. Refrigerant is toxic. Can you say pulmonary edema?

 

You can get a $20 bottle w/guage at walmart. Look for the gray metal tube with the black cap (if i'm thinking right i want to say it's on the passenger side). If the ac is on that tube will be cold. Turn truck on, turn ac on high, place end of bottle rubber tube on to where cap once was, check guage. If more is needed, proceed to add.

The instructions on the bottle are all there and easy to follow.

 

Unfortunately, those gauges are cheap and inaccurate. Get a middle-quality set from autozone. It will get you both the high and low side pressures. It will still only give you a guess as to how much refrigerant is in the system. Won't tell you if there is a leak.
(Not a flame, just a heads-up)

 

The guages will tell you nothing other than operating pressures.

1. Evacuate system with a recovery machine. This will tell you how much was in there.
2. Apply a vacum to the system and make sure it holds a vacum with 0 loss for 20 or 30 mins.
3. A quality A/C machine will tell you if any oil was removed with the Freon.
4.If the system held a vacum you can recharge it with the proper amount of Freon. Note: more isn't better. Most A/C machines will allow you to inject the lost oil into the system as you recharge it.
5. After recharging start the truck and check the pressures. This is the only time the "guages" really do you any good on a simple recharge. The specs for the pressures vary with temp so you'll need a chart to see if you have the proper pressures.....

This is the minimum # of steps and procedures to do it correctly.....

This is a small portion of the "legal" method as perscribed by the BAR (a group of morons who know nothing about auto repair) for A/C service in CA. And people wonder why it cost's as much as it does.....

 

Yes operating pressures, and what's wrong with the system. Ie. Excessive pressure=blockage, excessive low pressure=very low refrigerant. Won't tell you if you have a leak, slightly low refrigerant, etc. You need an evac for that.

 

you must have an EPA license in order to handle refrigerant. fill it in the garage there are people out there that will take pictures and turn you in for a 10000$ reward. also i kind of doubt that you are low on refrigerant, have you added the incabin air filter mod to your 2005? is it really dirty?

 

Think I'll pass on diy. I did not do the cabin filter mod. Thanks for the advice guys.

 

buy the can with a gauge at any autozone or whatever. Its easy.. you guys are paranoid!

 

Yup, buy the gauge at autozone/napa/kragen. Hooks up to the low side port. I believe the ports are idiot proof, can't hook up to the wrong side.

The gauge is marked low, high, proper charge. You want to read the gauge while the compressor is running. Very easy to top off with the gauge also. Usually they sell the gauge with a can of r134a.

Legally, you can buy r134a in a small can. But I am pretty sure it's illegal to actually work on the system yourself. I would not worry about it as long as you are just checking and topping off. Most people don't know or give a shit what you are doing under your hood anyway. I wouldn't want to create a cloud of escaping refrigerant for them to see, but otherwise you should be fine. I have a friend who has done it many times!

 

That's the most confusing...I think the illegal part revolves around what is meant by 'work on the system'. I think it's legal to buy R134 in small quantities (cans) (duh...it's all over WalMart and PepBoys) and recharge your system. But it might be illegal to open it up, as to remove/replace parts, or buy large cylinders with out a certificate.

Found on WikiHow http://www.wikihow.com/Fix-Your-Car%27s-Air-Conditioner :

"LEGAL WARNING! - Checking for refrigerant by poking something in the fitting and looking for venting is ILLEGAL as it releases refrigerant into the atmosphere. (Please don't do this with R-12 especially!) Second, it's also ILLEGAL to put more refrigerant into a system known to leak (because, again, you're letting it vent to the atmosphere, albeit more slowly). [Note: The EPA web site disagrees with this statement.][It is NOT illegal to top off a leaking system unless there is a state or local law against it.]
This is why you may not find a repair facility that will simply top you off, if they suspect that you need to repair a leak first. If you repaired the leaks and failed components yourself, it is legal to recharge the system with 134 without a license, but not R-12. (However, getting a license to handle R-12 is easy online, and runs about $20.)"

 

Correct not to vent to atmosphere (they are classified as ODS's and pollutants by EPA)...but R134a refrigerant is not particularly toxic. Neither is R12.

I think you're confusing the by-products of burning them which most certainly are. It's a not uncommon confusion because an old method for finding leaks was to use a flame which changes a bright green color in the presence of Freon. Not used any more...for obvious reasons.

 

It is illegal to recharge your own system unless you hold a section 608 epa license. thats the one for cars. that being said everyone is doing it. just dont do it in a car park full of people or if you see someone with a camera get it from them. I am in no way supporting illegal action or suggesting that you do this yourself. the R-134A that you can buy from autozone is HOTSHOT this means that it already is loaded with oil also. if there is a leak which is the only way that it could be low the oil has most likely not leaked out unless the leak is in the compressor. This is not a big deal in a car ac system it will become a really big deal if you recharge your system like 5 times it will have a massive overcharge of oil and very little refrigerant. pulmonary edema dont worry about that at all. with these tiny amounts thats not going to happen unless you sprayed like 2 or 3 cans out on the inside of the truck with the doors closed, windows up.

 

And in case you wanna get the license:

http://www.epatest.com/608/

It's $25 to take it. Very interesting site...

 

Refrigerant doesn't need to be "topped off", it doesn't burn off or wear out. If the system is low on refrigerant it leaked out and the leak has to be repaired, then the system is evacuated and recharged. The easiest way to check your A/C is put a thermometer in the vent, if the temp is 20 degrees or so cooler that outside air temp the system is working. Leave it alone.

 

No matter how effective your seals are some refrigerant is going to seep out over time. Adding from 1/4 lb to 1/2 lb of 134a refrigerant with a little bit of seal conditioner to a five or six year old air conditioning system helps bring the cold back and can help extend the service life of the entire a/c system.

 

Motor vehicle A/C (MVAC) systems are covered under section 609 and it is legal to service MVAC without certification (license) if you aren't being paid...that is, it's not 'service for consideration'.

Mainstream Engineering Section 609 Manual
It's in the manual at: http://www.epatest.com/609/manual/609_section3.jsp

 

Refrigerant charge volume on 06 tacoma 570 to 630 g (20.10 to 22.22 oz)

hopelly this helps

 

In order to charge the system properly you need two things a set of gauges and a decent thermometer other wise you are guessing. Pressure follows air temp. Charts are on line. It is very easy to over charge an R134 system by adding R134 just because you did not think it was cold enough.