Shifty762

My 87 22R has the factory cooling installed still running r12 as far as I know. When I activate the "A/C" button on the dash, the compressor engages as well as the VSV for the idle up.

There are no strange noises, all damper doors seem to work, yet there is no cooling effect. I have noticed the idle up is not tuned correctly as the RPM's barley come up and when the compressor clutch engages it doesn't put any noticeable load on the engine.

What could be causing this? I would assume the pressures are correct since they are not triggering the High and Low pressure switches and cutting off the compressor.

What would cause this?


Thanks in advance,

highonpottery

iTrader: (1)

my truck's A/C does the same thing. took it in for diagnosis and they said it's related to some valve in the system located under the dash in the cab's heat exchanger unit. they said besides a leak, these valves are usually the part that causes the A/C issues since it gets stuck closed when not in use frequently. since it's so deep in the dash and everything has to be taken apart to get to it, it's not a cheap repair - of course! my quote to have it fixed was around $350...2yrs ago...

you can check the sight glass to see if there's sufficient fluid in the system, but that wouldn't help you if you've got a blockage in the line keeping the fluid from exchanging heat in the cab. i dunno what else to suggest. i'd suggest doing some searching.

myyota

You refering to the expansion valve, they can go bad and you have to remove the dash to get to the evaperater under the dash to replace it. not a hard job but if your paying shop to do it there is a lot of labor involved to do it. If possible i would pull the fan housing out from under the dash and make sure the duct between the fan and a/c isn`t plugged with leaves, that`s a common problem the restricts air flow through the a/c.

Shifty762

I have been thinking about pulling the dash appart to dust everything while the carpet is out. It was a farm truck before so its really dusty. I'm really ADD about some things.

Is the dash pretty simple to take down?

How is the valve fixed; a solid thump from a ball peen?

If it needs replacing do I need a recharge? Its R12 I think.


Thanks for the assistance,

myyota

Removing the dash is not that hard, its just a matter of taking everything loose and finding a few hidden bolts. Ive replaced heater cores in 86 4Runners before, so i have experiance removing the dashes. To replace the expansion valve you have to remove the freon and pull the evaperator out of the truck and remove the plastic box that its in and replace the valve, then put it all back together and have the a/c recharged. Cleaning the heater ducts is also a good idea, they get very dirty inside. On my 4Runner the heater ducts were very dirty inside.

Shifty762

How do I go about recharging? Is there anyway to recharge with R12. From the reading I have done here it seems like converting to 134 is hit or miss, mostly miss with seal issues and trouble flushing teh system before its addition.

I know I can get R12 through ebay but I have no clue when it comes to air conditioning.

highonpottery

iTrader: (1)

yeah, i forgot to mention that evaporator. might as well replace it while you've got access to it.

to evac. the system, you've gotta use an A/C vacuum machine to properly collect the R12 since it's an ozone contributor. then after you do your repair, check for leaks then put the r12 back in and top it off.

the systems are actually fairly straight forward, it's just all the stuff having to do with reclaiming the fluids and keeping it out of the air that makes working on it so difficult. also, i believe some places will even buy your old r12 because it's of value.