Questions about A/C - Toyota Nation Forum : Toyota Car and Truck Forums

azncapcom · 05-31-2011, 11:50 PM

Wondering what is the ideal PSI? and also how much freon is ideal/full.

Also has anyone used redtek? I took the corolla to the mechanic to recharge the A/C, turns out he used redtek (which i couldve bought from a parts store and done myself). However, after a couple days it seems to have leaked as its not cold anymore again.

I was thinking of buying the recharing kit myself and also getting a can of their sealant. Has anyone that had a leak use their sealant and was it effective?

Buurin · 06-01-2011, 08:27 AM

Quote:

Originally Posted by azncapcom

Also has anyone used redtek? I took the corolla to the mechanic to recharge the A/C, turns out he used redtek (which i couldve bought from a parts store and done myself). However, after a couple days it seems to have leaked as its not cold anymore again.

I was thinking of buying the recharging kit myself and also getting a can of their sealant. Has anyone that had a leak use their sealant and was it effective?

I don't use redtek because I can't be sure what exactly is that stuff. Sale of r134a is restricted to professionals so if your professional could get the right thing and still use redtek, I'd look for another mechanic. One more thing, redtek and 134a don't mix. To switch to redtek one still need to get whatever stuff in the system recovered which is another professional job, more because of law than the $3000 machine needed for the task.

I'm still waiting for someone to come up with a R744 (carbon dioxide) AC retrofit system.

blb · 06-01-2011, 12:12 PM

Quote:

Originally Posted by azncapcom

Wondering what is the ideal PSI? and also how much freon is ideal/full.

There is no one "ideal pressure" for all cases since the pressure in your system will vary with the ambient temperature. The hotter it is outside, the higher the pressure will be in the system. The same holds true for tire air pressure BTW. The ideal gas law (PV=nRT) comes in to play here for those that remember high school chemistry. The ideal amount of refrigerant in the system is the manufacturer's specification givien in terms of pounds of refrigerant. The only way to get that perfect is to evacuate the system and add exactly the specified amount of refrigerant. With that said, what is normally done on a recharge of the system, is not to evacuate the entire system, but to hook up gages to both the high and low pressure sides of the system and add refrigerant until the pressures look close to normal as read using the temperatures and pressures shown on the gages, and there are charts you can refer to to take into account the ambient temperature as you add refrigerant. A figure that will get you into the ballpark is about 30 to 35 psi on the low pressure side (suction side) with the compressor running and around 100 psi with the compressor not running.

However, in your case this is somewhat irrelevant. Given the fact that you have a leak large enough that the refrigerant leaked out in a couple of days, that, in my opinion, is too large to hope to fix with a sealant, and the leak must be found and repaired properly. The system will need to be evacuated so it can be opened up and repaired, and then the system will need to be pumped down with a vacuum pump to remove all air and moisture ( a vacuum of 29" Hg for 30 to 45 minutes is recommended) then the proper charge of refrigerant can be added. This is not difficult work but you must be clean, have gages, have a real vacuum pump (not the type that works on a venturi principal) and several cans of 134A.

azncapcom · 06-01-2011, 03:26 PM

I did find it odd when i asked how much it would be to check for a leak... and the guy said it would require topping it out and then seeing if there is a leak... i swear people use a pressurizer or something to test if theres leaks. Anyways, he checked and said there was no pressure in the system at all, so he added a can of r12a redtek... it seemed to have worked and he said he didnt see any signs of leakage. Then 2 to 3 days later... its not blowing cold anymore (it wasn't blowing that cold to start with.

Since its r12a it is legally sellable to everyone. Im not sure if whether i should bother trying with the sealant or not...

how many ounces does the system take for a full charge when empty?

Also how much would it cost if i wanted the leak to be fixed professionally? Summer is here and its getting really hot. Not sure if i can survive the whole summer again without A/C... last summer was already bad when it wasn't even that hot.

Should i spend the $70 or so on a sealant plus recharge kit?

also the mechanic only filled one can of r12a and he said it should be enough... im guessing he didnt want to pay for more cans? that way he'll be making less money?

pdq · 06-01-2011, 04:38 PM

There's definitely a leak in your AC system. Adding more refrigerant is a costly waste, as it will just escape to the atmosphere. And those cans of sealant are junk.

You should see a mechanic to find the leak, as you need expensive "sniffers" to find them. If the leak is repairable (ie a shrader valve needs replacement), those are cheap fixes. It could also be a leaking compressor, which would cost a few hundred to replace with a brand new compressor. And if it's a compressor, replace with a new, not remanufactured compressor, as the reman'ed often leak again.

azncapcom · 06-01-2011, 11:21 PM

Quote:

Originally Posted by pdq

There's definitely a leak in your AC system. Adding more refrigerant is a costly waste, as it will just escape to the atmosphere. And those cans of sealant are junk.

You should see a mechanic to find the leak, as you need expensive "sniffers" to find them. If the leak is repairable (ie a shrader valve needs replacement), those are cheap fixes. It could also be a leaking compressor, which would cost a few hundred to replace with a brand new compressor. And if it's a compressor, replace with a new, not remanufactured compressor, as the reman'ed often leak again.

would it mean my compressor is working if my defroster works properly?

Buurin · 06-02-2011, 12:01 AM

Quote:

Originally Posted by azncapcom

would it mean my compressor is working if my defroster works properly?

Defroster are heating wires on rear windshield and have nothing to do with AC.

azncapcom · 06-02-2011, 05:31 AM

Quote:

Originally Posted by Buurin

Defroster are heating wires on rear windshield and have nothing to do with AC.

im referring to the front windshield when you have it set to defrost/defog mode. The A/C light comes on to turn on the compressor to help defog/defrost faster?

blb · 06-02-2011, 07:47 AM

If you want to see if the compressor is working, open the hood, look at the front of the compressor, have someone turn on the a/c and see if the clutch engages and the very front of the compressor starts spinning. If it is not, it doesn't necessarily mean the compressor is bad since there is a low pressor sensor in the system, that disables the compressor (to protect it from damage) if the refrigerant pressure drops too low.

In your case, you must find where the leak is before you can go any further, and given the fact that your system completely leaks down in a couple of days, you should be able to find the leak easily by using a soap/water solution applied to all hoses, connections, condensor, etc (looking for bubbles) if you don't have access to an electronic leak detector. Used electronic leak detectors can be bought on ebay for cheap.

You may want to consider paying someone to find the source of the leak for you, and then you can decide if you want to attempt the repair yourself or not depending on where and what is the source of the leak.