I recharged the A/C and put something like 20 oz to 24 oz ,and A/C is cooling good so far.But when I was charging a/c if I turn all a/cs on inside(the front,med and the rear) the gauge passes blue to yellow line if turn on the front only the gauge goes down to mid blue (I got the can with charging hose from walmart).
First time doing this.

 

You're going to have to first explain what you mean by "tool".

 

I'll tell you from a professional standpoint that those cans can get you into trouble. They have additives in a lot of them that are questionable too. I'm not sure what you mean by the colors without seeing the gauge and I'm not traveling to walmart to check them out. If you posted pressures that would be better. I'm assuming blue is the "green" zone.... and yellow would be high. The colors then indicate pressures. I suppose it's possible you have some sort of an obstruction in the line, causing the pressure to rise like that. But, you can't properly diagnose this unless it's been properly recovered, vacuum pulled, and properly charged. You might even benefit from a new drier and orifice tube while at it. Also, with using only one "gauge" you have no idea what the pressures are on the high side.

 

That was the green (low),blue(good),yellow(alert),red(high).Thanks for ur reply.

 

+1 here, you need to use the proper manifold gauges to recharge the system correctly. Autozone has them for rental, though Advance Auto & Oreillys don't. When I recharged mine 2 months ago, I bit the bullet and bought a set along with a can tap. Also, Walmart has plain R134a for $4.88 per 12oz can. My 97 Expedition with rear A/C used 5 cans. The exact amount you'll need is on the emissions label under the hood, I believe it is 56oz for trucks with rear A/C.

The reason your "guess-o-gauge" is sweeping is because the compressor is cycling on and off because your system is either undercharged or overcharged. This is why you need pressure readings on BOTH sides. Go get the proper gauges and get some pressure readings.

In lieu of the proper specifications not being in my FSM CD, I have found that ~50psi on the lowside gauge and ~225psi on the highside gauge will produce nice, chilly a/c. This is what I charged the system to 2 months ago. When recharging due to a leak last week, I charged it to 50/180 and am still quite pleased with the results. The reason I didn't go all the way to to 225psi on the highside is that I know my system is leaking somewhere and I've not had the time or space to thoroughly examine the system to fix the leak properly.

 

I will do that ,by the way where did u get your gauges.I did get that 4.88 tooand looks like I am off 3 more cans.I will get the tool and hopefully I can figure out how to use it.

 

Mine are Matco, but for home use Harbor Freight should suffice. They're halfway decent gauges

 

I got mine from Oreilly's as I needed to get things done the same day. Harbor Freight's gauges should be fine too. The only flaw I can see (more of me nitpicking, FYI) on Harbor Freight's gauges is that the service port valves might be difficult to use, specifically the highside valve. My set has the valves about 4" back from the service port connector.

Just keep in mind to NOT open the big red valve with everything hooked up. Doing this connects the High Pressure side to the middle refrigerant can hose. I did this once by accident and it dumped refrigerant out, nearly making the can burst. The small red valve stays open to monitor the highside pressure.

 

I found this(made in usa) mastercool(66661) brass manifold gauge set,72.68 at amazan.I will get it in a week or 10 days.I let you know how did it go.ty

 

Keep in mind that the system doesn't magically empty itself. The most recent time I had to charge mine (charged to 55/180, it wouldn't go any higher on the highside), it was back to hot in 3 days. I suspect the accumulator as I heard hissing near there.

REALLY not looking forward to doing this...

 

So after doing this,it could be a leak somewhere right?

 

Of course there is, that refrigerant doesn't just disappear as if by magic as Travis noted.


If that was immediately after shut-down and only lasted a bit, it's normal. It's simply the pressure equalizing through the orifice tube and is often quite audible if you listen for it.

 

You are right Travis explained everything.I let you know next week after getting the tool.

 

These were my tests today between one o'clock and two,97-98 out there:
After hooking the low and high side both valves were closed

After starting the truck & A/C on Hi only at the front:

LOW SIDE-39 HIGH SIDE-195
After turning rears on and Hi and 10 minutes later:

LOW SIDE-60 HIGH SIDE-245
It stayed that way for next ten minute,with windows down and up didn't make change.
Have I done it right?

 

The second set of numbers look pretty good to me, despite not having the proper figures from Ford. Is it blowing nice and cold? Generally speaking, you are supposed to turn on both front & rear A/C, then start charging the system so the R134A Refrigerant circulates through the entire system.