4 runner 94 air problem

[efitz]

If anybody has any ideas what to do id appreciate it. My 4 runners air conditioning will work then not work. or vice versa. I have no idea what to look for. its like there is a sensor or valve that shuts off or on......thank you

[RIP]

More info would help. Does it quickly cycle on and off several times per minute or does it work several minutes, hours, days at a time? Have you had it serviced lately? Does it make a noise like a squeal or a hiss? When it works does it put out at least 30 Deg below outside air temp? If you have a light on the A/C on switch, is it blinking on and off or on steady?

Could be electrical or pneumatic and any number of components in those areas. The primary keys to a working system is freon servicing and an operating clutch on the compressor. Low or over serviced freon or no clutch engagement = no cool air.

You may have moisture in the system that is freezing and blocking a coolant line. You may have a sticking proportioning valve (usually under the dash with the evaporator). The receiver dryer (cylinder about a foot long) could be saturated with contaminents. These are things that need to be determined by a pro.

Some simple things to check: is the drive belt to the compressor tight enough? Normally but, not necessarily, you'll hear the belt squeal as the clutch engages if it's loose. If that's the case you'll see the light blink on the turn on switch. If the belt is over three years old change it. Measure the temperature at the center vent, on high with the recirculate button pushed. Should be at least 30 deg below the outside air temp. On a hot day it might be a tad lower until you give it some gas. If it's lower it's low on coolant. Air bubbles in the sight glass on top of the drier and a hissing noise under the dash when you turn the car off is another indication of low coolant. When the A/C button is on and you don't have cool air tap/wiggle the A/C power relay. If the clutch on the compressor engages, change the relay. You may want to change it anyway. Your manual should say where it is. Wiggle the wires going to the clutch with the A/C button on. If the clutch starts and stops you have an intermittent open in the wiring. Remove the connector on the compressor/clutch and check for corrosion. Check the power relay socket for corrosion.

The last time I saw this was on my 94 Camry three years ago. It turned out to be a bad proportioning valve. The system would work great for anywhere from ten minutes to an hour then die. Sometimes it would start working again that day and sometimes not. It had a mind of it's own. Cost me $300 to have it replaced and the system reserviced.

[MT-2500]

Originally Posted by efitz

If anybody has any ideas what to do id appreciate it. My 4 runners air conditioning will work then not work. or vice versa. I have no idea what to look for. its like there is a sensor or valve that shuts off or on......thank you

As said need more info.
But a few cautions.

And post back pressure readings would help.


Wal Mart DEATH KITS

You cannot properly and safely recharge an air condition system with them.

The one side stop and go gauge does not tell you what your system is doing or is over charged or undercharged.
A overcharged or malfunction air condition system can reach over 500 lbs of pressure.
Enough to blow up that can or system and freeze you at first and the burn you or blind you and if any propane /butane in there blow and light you up.

The stop leak crap and who knows what kind of oil in the kits there will stop your system for sure.
Just like pouring super glue in it.
And some kits even contain freon with a butane mixer.
Good for a big blast.

If you are going to do it do it right and safe.
Here is what you need to start with.
http://www.ackits.com/merchant2/merc...uct_Code=66773

In the older days you could just throw in a can and go.
But over the years just adding freon is getting harder to do.
Newer systems have to have the correct amount of freon down to the ounces.
Most will need pumped down and vacuumed down and the right and amount of oil and a set amount freon charge installed to get the air to cool right and the system to last.
If an air condition is low there is usually a leak that needs fixed and also a lose of lubricating oil from system.
Also air and moisture enters a low system
If you are going to try to do it get the proper type air condition gauge set with the low and high side gauges.
Hook up the gauges and get a reading with compressor running at idle and at 2000 rpm on the high and low side.
Post back pressure reading and we can help you.
MT