Hello,

My 06 EB Expedition 46,000, started making a hissing sound in the rear passenger area. I opened the rear hatch and the noise is coming from the AC hoses behind the trim panel on the right rear of the car. I have read in the forums that my freon is probably low.

So I removed the caps on the hi and low connectors. When I removed the hi side it made a hissing, spitting noise. It's bubbling yellow oil inside of the hi side fitting, so the valve is leaking on the hi side.

1. What should I replace?
   
2. What should my pressures be? I have gauges.
   
3. I need a part for my gauges, maybe you guys can help. My gauges won't connect to 134a cans. I think all the hoses are for r-12, but it has adapters to go from r-12 to 134a on the car. The yellow hose in the middle has an r-12 connection on it - without any thing to pierce the can. So I need to go from a 134a can to r-12. What's the best solution?

Thanks!

Brian

 

Current pressures:

Hi: 125 psi
Low: +20 psi

AC is not blowing cold.

Brian

 

For starters you have fix the leaking schrader valve on the high side. It might just need tightening or you might have to unscrew the valve and replace the o-ring. Before you unscrew it, you will need to drain the system.

Pressure should be more like 250 high and 40 low for proper cooling.

Does your yellow hose have the r-12 valve built onto it or is it just a female connector that screws onto an r-12 valve?

 

You can get the conversion kit for $40
R-12 To R-134a Gauge Adapters

Or you can just get a new set of gauges for $50
Harbor Freight Tools - Quality Tools at the Lowest Prices

 

Those are my gauges. They won't screw on to a can of 134a. They fit the car fine.

 

Here's the hose that comes with the harbor freight gauges. It won't screw on to the 134a cans you get at Walmart.




[QUOTE=alloro;7198298]You can get the conversion kit for $40
R-12 To R-134a Gauge Adapters

 

It's not supposed to screw onto the can. You're supposed to screw a valve onto the can, then the hose connects to the valve.

You can buy this valve in probably any auto parts store for about $8. It will look something like the one here, although the handle might be different on some.
Mastercool - R-134a Can Tap Valve - Charging - MSC85510

 

Yes! That is exactly what I've been looking for. I went to a NAPA and Autozone, neither had that.

Thanks

Brian

 

Really? That's odd I've seen the valves in Autozone many times. Maybe because it's not summer and the demand is low they take them off the shelves. Did you ask them if they had them in the back? One time when I needed some R-134a in the winter, they had none out on display. I asked and I was told they keep it in the back in the winter because it's not a big seller that time of year.

Do you have an Advance auto parts store near you? They have this one for $7.
While we find your parts, please enter your ZIP Code at PartsAmerica.com

 

You might want to check the accuracy of your low side gauge. The Low Pressure Cycling Switch should cycle the compressor off at 25-30psi. It's also possible that the switch has failed. The low side shouldn't be that low with the compressor running.
That 125psi on the high side may be normal, depending on the ambient temperature. That's about right for 50 degrees, ballpark for the high side is 2.5 times the ambient temp.

Don't add refrigerant until you know for sure it's low!! If it is low on refrigerant, you really should find and repair the leak. If it's not actually low, you risk overcharging the system and damaging the compressor when the temps approach summer levels.

The High side port most likely has a rubber ball type valve in it and it's not uncommon for them to leak. If the service cap was installed properly, that is NOT the source of the leak. The cap is actually the primary seal for the port, as silly as that may sound. The port "can" be replaced but the system must be recovered first. The port is screwed into a fitting on the line.

One last thing, the yellow hose in your pic is an R12/R22 hose. It will not attach to an R134a can tap, the connection is a different size. You can buy an adapter kit as mentioned, but they made all of the hoses and fittings different for a reason. Cross contamination between the 2 refrigerants and their respective oils is a bad thing! You really should source a proper R134a gauge set.

 

Thanks LSRX

Here's a picture of the hi side valve. It has a slow leak around the edge.

The line below was covered in oily dirt that leaked past the service cap. It had been leaking for a while. But I think it's a very slow leak.

You bring up good points about pressure and air temperature.

Yesterday
Air Temperature 94F
I added two cans of 134a.
Low side 45 psi
High 200 psi
The AC was blowing cool, not ice cold.

This morning
Air Temperature 43F
Low 25 psi
Hi 90 psi
I can't tell if it blowing cold because the inside of the car is 43F.

So I thought all the freon leaked out, but maybe it's just the air temperature?

Also, when I was driving the car last night I kept smelling a sulphery smell, kind of like an oil well or a fart. Could that be an interior AC leak?

Thanks!

 

Ok. At those ambient temps you were certainly low on refrigerant. (It's 20 degrees here) The oily dirt around the port is a dead giveaway of a leak, so make sure the rubber seal is in the service cap and in good shape. It shouldn't leak past the cap even if the valve inside leaks a bit.
That's a schrader valve in there, I guess Ford finally gave up trying to save .03 on the cost by using the rubber valves.

Ideally, you would have the system recovered, evacuated and then charged by weight of the refrigerant. That's the only way to actually get the correct charge.
You can get close, especially at your rather high ambient temps, by following this procedure:
-Engine at 1500 RPM steady.
-Max AC, High Blower, doors open.
-Charge 1-2 ounces at a time while measuring the temperature of the evaporator inlet and outlet lines where they enter the firewall/plemum.
-Allow 2 minutes between refrigerant "shots" for the system to stabilize.
-When the temp of the inlet and outlet are the same, you are fully charged.
-If the outlet is slightly warmer but adding a "shot" doesn't effect the temperature, you have reached max charge. Close the doors for a few minutes and recheck.
-If the outlet of the evaporator gets colder than the inlet, you are overcharged and risk getting liquid refrigerant into the compressor.
-You should see roughly 2.5 times the ambient temperature for the high side pressure and the low side will be within 2-4 degrees of the vent outlet temperature.

Hope this helps.

BTW. If you check the static pressure (system off, cold engine) you will notice that the pressure is within a few degrees of the ambient temperature. That a good rough indicator of system charge.