2008 Ford Explorer AC compressor short cycling

Messages
9
Location
Oklahoma
008 Ford Explorer 4.0L manual climate contol.

Wife was driving it the other day and the AC stopped working. Would blow hot air out of the vents then only 2 times it became cold like normal then went back to hot air coming from vents.

I checked the motors in the interior, the motor on the driver side is working and the passenger side is working also. When I turn the temp knob, I do get hot air when turned to warm.

It acted like the system was low on freon, the compressor at idle would cycle on and off every 3-5 seconds. The compressor wouldnt run long enough to allow cold air to come from the vents. So I bought one of those easy connect R134A cans and put a little freon in the system. The compressor short cycle became a little better and I was getting cold air from the vents.

However, I took it for a test drive and when the compressor would engage, the idle would drop low on the engine and you could see when the compressor would engage and dis-engage by looking at the tach and the feeling of the idle. Also, the mechanical fan was engaging more than I though it should. Sounded like a 18 wheeler. The temp outside at this time was only 75 degrees, so I don't think it should have been working that hard to keep it cool.

Fast forward to today, I was able to connect my AC gauge manifold set to the low and high sides. The gauges acted like the system was over filled with freon. I slowly evacuated the system to get the pressures back to somewhat normal, put some UV dye in the system and let it run for about 10 mins to check for leaks. During the 10 mins, the compressor cycle every 5-10 seconds at idle. I found no leaks in the system.

So I decided to completely evac the system and put a vacuum on it. I put a vacuum on the system for 30 mins and let it set with the vacuum off for 30 mins. The gauge needles did not move so I am pretty sure the system does not have a leak.

I found that the R-134a capacity of my system is 31 Oz.......I hope that is correct, was difficult to find.

So I recharged the system with one 18 oz can and one 12 oz can of freon....so that equal 30 ounces of freon.....so it should NOT be overfilled now. I also installed a new low pressure switch that was at the accumulator.

The compressor is still short cycling. The symptom is worse now, the compressor only stays on for 3-5 seconds. Won't stay on long enough to even start cooling the interior or get cold air out of the vents.

Here is a video of the gauges after I recharged the system (the temp outside was 70 degrees):


Here is a video of the compressor short cycling (the temp outside was 70 degrees):

Here is a picture of the gauges with the engine off:
explorer.jpg


What do I need to be looking for or replace in order to get cold air again?
 
Messages
184
Location
New York City
You have to find out what's making the computer shut off the compressor.

For the compressor to cycle, It needs proper low side pressure, high side pressure, low side temperature and maybe high side temperature.

Based on your gauges, The low side pressure dips to 20Psi when the compressor disengages. Most AC modules switch compressors off when the low side PSI drops below 20 PSI

Seems like there is a clog somewhere.
 
Messages
21,846
Location
Apple Valley, California
You have to find out what's making the computer shut off the compressor.

For the compressor to cycle, It needs proper low side pressure, high side pressure, low side temperature and maybe high side temperature.

Based on your gauges, The low side pressure dips to 20Psi when the compressor disengages. Most AC modules switch compressors off when the low side PSI drops below 20 PSI

Seems like there is a clog somewhere.
The suction side drops real fast! It is pulling against a blockage
 

relentless85

Thread starter
Messages
9
Location
Oklahoma
I believe it has a orfice tube. I think I saw a video of a line that is near or below the accumulator, has a connection that has to be undone then the orfice tube is inside that line.

What would cause the orfice tube or system to become clogged?

Is the compressor starting to go bad, possible pumping trash into the system?

Is there anywhere else that I need to look for a clog at?
 
Messages
21,846
Location
Apple Valley, California
I believe it has a orfice tube. I think I saw a video of a line that is near or below the accumulator, has a connection that has to be undone then the orfice tube is inside that line.

What would cause the orfice tube or system to become clogged?

Is the compressor starting to go bad, possible pumping trash into the system?

Is there anywhere else that I need to look for a clog at?
The condenser is right after the compressor. That gets the junk first.

If the system is full of junk we will have to see what it is. Since the compressor is still working and not making noise I assume that the dessicant in the accumulator let go. Pull the orifice and report what you find
 
Messages
404
Location
CA
I believe it has a orfice tube. I think I saw a video of a line that is near or below the accumulator, has a connection that has to be undone then the orfice tube is inside that line.

What would cause the orfice tube or system to become clogged?

Is the compressor starting to go bad, possible pumping trash into the system?

Is there anywhere else that I need to look for a clog at?

I would replace the accumulator as it's replaced anytime the system is opened anyway. It looks like a classic clogged accumulator. It's a cheap enough fix.

To determine the cause of the clog look at the color of crud coming out of the compressor into the screen. If it's shiny then the compressor is failing. If it's milky in color then the filter material in accumulator has broken apart.

Admittedly I have not worked on a AC system in over 20 years so I could be way off base. It's worth checking though.
 
Messages
14,799
Location
Illinois
I just had this problem in my 2007 Fusion. It's the sensor behind the dash near the evaporator. The sensor is about $50 but on my Fusion the dash has to be elevated to access it. $500 for labor. I timed my compressor and the clutch only engaged for 3-4 Sec. and only cooled to 55-58F. This sensor controls that. Now the clutch engages for 11-12 sec. and cools down to 40F.
 

relentless85

Thread starter
Messages
9
Location
Oklahoma
I just had this problem in my 2007 Fusion. It's the sensor behind the dash near the evaporator. The sensor is about $50 but on my Fusion the dash has to be elevated to access it. $500 for labor. I timed my compressor and the clutch only engaged for 3-4 Sec. and only cooled to 55-58F. This sensor controls that. Now the clutch engages for 11-12 sec. and cools down to 40F.

Do you happen to know what this sensor is called and what its specific purpose is? I don't want to throw parts at it.

I am looking at parts now. I would definitely replaced the accumulator if I have to open the system. Debating on if I should go with OEM Ford/Motorcraft parts or aftermarket parts. I'm pretty sure it has a non OEM accumulator installed on the vehicle now. The Motorcraft accumulator is $$$$.

Last night when I was testing the temp coming from the vents, it was coming out at around 60 degrees F
 
Messages
14,799
Location
Illinois
Do you happen to know what this sensor is called and what its specific purpose is? I don't want to throw parts at it.

I am looking at parts now. I would definitely replaced the accumulator if I have to open the system. Debating on if I should go with OEM Ford/Motorcraft parts or aftermarket parts. I'm pretty sure it has a non OEM accumulator installed on the vehicle now. The Motorcraft accumulator is $$$$.

Last night when I was testing the temp coming from the vents, it was coming out at around 60 degrees F
It's called the interior temp sensor.
 

relentless85

Thread starter
Messages
9
Location
Oklahoma
Does the evaporator temp sensor apply to AC systems that are manually controlled. I don't have any of the automatic climate control or dual zone climate contol. I only have knobs, no buttons.

I'm looking on the Ford parts website, I don't see this evaporator temp sensor on the diagrams yet....if there is one.
 
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Messages
2,974
Location
USA
There is usually no evaporator temperature sensor on an orifice tube system. The pressure switch stops the compressor before the evaporator can freeze.

Apples vs oranges, etc.
 
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relentless85

Thread starter
Messages
9
Location
Oklahoma
Looking at the diagrams from Ford, I see the evaporator temp sensor on the models with the Dual climate control/electronic climate control, not the manual climate control. So I am assuming my model does not have that evap temp sensor since I have manual non dual climate control.

Any recommendations on part brands besides OEM? I see 4 seasons and GPD brands.
 

relentless85

Thread starter
Messages
9
Location
Oklahoma
Ok, I’m finally going to get around to replacing the orifice tube and the accumulator this weekend to see if that fixes the problem.

Do I need to add PAG oil to the new accumulator or orifice tube when I install them?
 
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