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time to fix the AC help please

blaster_works on Sat December 11, 2010 8:47 AM User is offline

Year: 1992
Make: toyota
Model: 4 runner
Engine Size: v6
Refrigerant Type: r12
Country of Origin: United States


i have 1 1992 toyota 4 runner . several years ago the ac system died . i went out and bought gauges etc and the system was low . so i found some of the old refrigerant on craigs list and recharged it. this lasted about 2 months and then it faded away. I just moved to texas and i want it to be like new again so what is it going to take..

my gut feel is that it is an original compressor and the seals are most likely shot.

so new pump
if i am going to convert it do you need to change the "sorry for the lack of terminology" the condenser radiator?

what if the leak is somewhere else is there an easy way to find it.

i am a pretty good mech. but really don't feel like pulling the dash ...

Cussboy on Sat December 11, 2010 10:06 AM User is offline

You need to find the leak first, not just guess. There are several ways to find leaks:
1. Visible oily residue at connections, crimps, compressor seal
2. Soap bubbles (temporarily fill with R-12, R134a, dry nitrogen)
3. Uv dye in system, with UV light & goggles
4. Electronic leak detector

Good AC mechanics can use a combination of the above techniques.

My opinion: take it to a dedicated auto AC shop, have them find the leak, then you fix it. And I agree to keep it R-12.

blaster_works on Sat February 19, 2011 4:06 PM User is offline

ok i have a new problem

i picked up all the tools to work on this sytem.
i put the sytem in vacuum for 30 min
i verified it stayed at 30 with the pump off for 30 min
i put uv dye in the sytem
i started charging the system
low side went to 75 psi
high side was at 75 pump off and 80 with the pump clutch on.
i turned off my tank and watched the presures and they were the same

Sounds to me like the clutch or the pump is shot is this correct ??????

this vehical has 240,000 on it so it has done its job
if it is bad what is the best brand denso ?


TRB on Sat February 19, 2011 6:48 PM User is offlineView users profile

How much refrigerant is in the system now? Try and get a full charge and then post the readings.


When considering your next auto A/C purchase, please consider the site that supports you:

blaster_works on Sun February 20, 2011 9:19 AM User is offline

that is all she will take.

i even pulled yhe low presure line and made sure i could get coolant through all the fittings and valves.
it acted like it wasnt pulling any thing in. but it did.
another thought would be that the air drier plugged didnt change it yet where will it be located ?

Dougflas on Sun February 20, 2011 9:32 AM User is offline

make sure both handwheels are closed on the guages. Only open the low side when adding refrigerant.

TRB on Sun February 20, 2011 10:23 AM User is offlineView users profile

I was referring to how many ounces?


When considering your next auto A/C purchase, please consider the site that supports you:

bohica2xo on Sun February 20, 2011 2:31 PM User is offline

You can't evaluate the system without a full charge on board. I show 27 to 30 ounces of refrigerant for that vehicle, along with 4 to 4.5 ounces of oil.

If the clutch was visibly engaged, and the front hub turning then it was working. If the clutch was not engaging, then it could be the gap, an electrical issue - or the A/C amplifier.

A plugged dryer usually shows a large pressure differential in the system.

An out of spec fitting or hose set can cause all sorts of odd problems, because it does not depress the schrader valve properly. When you evacuated, how long did it take to pull down to 25 inches or more?


"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

blaster_works on Sun February 20, 2011 10:17 PM User is offline

first i only open the low side to charge. i understand opening both would cause you not to have any presure. because it would flow from the high side through the gauges to the low side.

second i was also worried that my valves were not correctly opening the sghrader valves so i took the hose off at the fire wall and put it under vacuum. i put my finger over the hose and could feel the vacuum building on my finger. the valves are depressed and open. as far as how long to pull down to 30 from memeory about a minuit minuit and a half.

i unplugged and reconnected the wire to the ac clutch i could here the motor sound change and the pump make alittle more noise. i could also see the high side presure rise slightly. no change in the low side. this shows i have power to the clutch. and i can tell it is working some but it is posible its slipping.

as far as how much refridgerant in oz. i am not sure i a m not using a scale i was planning on watching presures. I am charging off a 30lb bottle.

any ideas at this point.

To me it apears that i am pulling in very little gas therefore pump or clutch.

TRB on Sun February 20, 2011 11:49 PM User is offlineView users profile

Not wise to charge by pressure. Use a cheap bathroom scale to weight your refrigerant. As mentioned, you sure the clutch is engaged when you are trying to charge the system?


When considering your next auto A/C purchase, please consider the site that supports you:

bohica2xo on Mon February 21, 2011 2:51 AM User is offline

A minute to a 30" pulldown? Either you have a ten horsepower vacuum pump, or you are not connecting to the system.

Your "test" only shows vacuum at the end of the service hose. The schrader valve is in the fitting on the system. You may not have even successfully evacuated the system, let alone add any significant volume of refrigerant.

Purge your service hoses to zero. Close the manifold valves. With the engine off, connect the low side hose to the system - what does it read? Now do the same thing with the high side hose. The readings should be the same.

What type of refrigerant are you adding?


"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

NickD on Mon February 21, 2011 5:21 AM User is offline

Says he purchased a 30# tank of old refrigerant, assume that its R-12, does have sight glass that is the most accurate means of charging these systems. Can use two sets of manifold gauges with the extra valves to switch over from vacuum to the tank without removing hoses that always lets air in. If he has never done this before, can see where he is having problems. Think we all did the first time, really have to watch those connections and valve settings.

blaster_works on Mon February 21, 2011 8:58 AM User is offline

ok. i have successfully charged this system and several other systems before so it is not my first time. to make sure all the valves were feeding r12 correctly i actually removed the low side hose on my vehicles at the firewall . i then turned on the pump . With the low side hose off and all the low side hoses all connected and low side valves on pump running. i felt the vacuum building in the system by putting my fingers over the open ac hose ports. i could feel the vacuum building in the system, and i could see the low side gauge start to build vacuum. the pump prior to my finger going on the hose was running wide open i could here it load.

then i reconnected the hose at the firewall back up "with a new oring and vacuumed the system.
i make sure the high side valve on my gauges is closed i didn't want to damage the gauge

after about thirty minuets i check the vac level it was at -30 So i turned off the low side valve on my gauges

then i unhooked the hose at the pump "so yes air gets in the hose"
then i hooked that hose to my tank
then i hooked the hose to the tank
turned on the tank
then i purged the hose to the tank. loose fitting at the gauges
then i opened the low side valve at the gauges and started the motor.

my fittings got a little cold but not as much as i normally see .. they were just slightly chilly not even cold......
now when i purged my hose it was cold..

so the only thing i am not sure of is when i vacuumed the system should i of opened the high side too?

this is when i started messing with the clutch wire . yes it had power yes the clutch grabbed just not sure if it slips or not.


"so i am ansewrring my own question. my problem is i didnt vacuum the high side just the low side....... " and at this point i will replace the dryer first. where will it be located ?

one last question. i am also injecting dye into the system for leak testing. the question is does it boil off ? do i need to add it again after vacuuming?

Edited: Mon February 21, 2011 at 10:01 AM by blaster_works

Dougflas on Mon February 21, 2011 4:27 PM User is offline

The dye will not boil off.

NickD on Tue February 22, 2011 10:28 AM User is offline

Could buy a four way manifold gauge, but buying two two way gauge sets is cheaper.

First gauge is connected to the ports, yellow is to yellow on the second gauge set, blue to vacuum pump, red to refrigerant tank with the valve closed.

For drawing a vacuum all manifold valves are opened, but make darn sure the valve to the tank is closed, switch on the pump and draw a vacuum from anywhere, including clear up to that refrigerant tank valve. Then draw a deep vacuum, nap time for me.

Both low side gauges should show a -30, could leave it to check for leaks, but not always reliable, compressor seal for one is seeing negative rather than positive pressure. Close off the blue valve leading to the vacuum pump, at this time and precharge the system by opening the tank valve. But for charging, the high side port from that gauge has got to be closed. If the temperature is in the 80's, doors open, AC on, blower at max, run the engine until you just get a clear sight glass. I leave it at that point. Couple of day or weeks later under the same conditions, if you see more bubbles, leave a couple in there, you know you have a leak. At that time the electronic leak detector comes out. But before even charging, can use a bit of R-134a to check for static leaks, even the EPA says its okay to leak off a can of this stuff, but you don't run the engine.

I don't favor dyes, bad enough adding oil as both these reduce your cooling capacity, let's not start an argument on this subject, each to his own on this matter. Last summer took my leak detector to my kids house, his contractor put dye in the system and couldn't find leaks. I found five of them with a black marker pencil. We knew there were leaks, refrigerant was leaking out. Kid called the contractor back and were repaired under warranty at the time.

Above procedure is for R-12, but can be used with R-134a as well with R-12 gauges and adapters, I love adapters, even have several for R-12 high side ports where they can't seem to make up their minds.

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