2010 Ford Escape AC. What I found

 

 

I finally got to attend to my Escape’s AC, and I wasn’t surprised by what I found.

If you recall the static pressures were taken after the car had been sitting for more than an hour, and with it not working right I had not turned the system on for more than a week. The last thing that was expected was for the high and low pressure sides to not be equalized. Upon seeing that they were not equal, and excessively high on top of that, this wasn’t just a broken car, someone had done something that made it even worse.

The normal routine for a car that a shop isn’t familiar with is to use a refrigerant identifier for the first step, and then a sealant test for the second one. The following photos are from my refrigerant identifier. It gets connected to the low side and a small sample is bled off of the system. In the past some people would substitute propane for R-12, hence the need to detect hydrocarbons, and other blends would use R22 to boost pressures in the systems under the assumption that would force more refrigerant liquid through the expansion valve or orifice tube. In an expansion valve system with a receiver drier, there may be some validity to that assumption but not so much with an orifice tube type system. One other contaminant is air. Just like R22 in an automotive system air, nitrogen and oxygen isn’t condensable into a liquid at the pressures and temperatures that the system runs at.  By not being able to make it change state between a liquid and a gas being in the system forces the pressures higher but doesn’t help the system produce any cooling at all.

 

So here is the first picture from my identifier, and it shows that there is no R-12, or R-22 in the system.

 

This second picture shows that the refrigerant is R134 but also that 15% of the sample taken was air. So how did air get into the system?

 

 

That we may never know but the identifier just confirmed the suspicion of why the pressures in the system were so high. There easily could have been a service performed where someone’s AC equipment hasn’t been maintained correctly and they may have drawn air into their recycle tank. Maybe the system was discharged and sat open for a period of time and then was charged without being evacuated. That one seems the most likely and could also explain the system having sealant added to it. As you will see in the next photos the sealant was responsible for the system stopping working.

 

 
 

 

   This is the receiver drier, some of the AC oil can be seen in the connection port and that is the outlet that the hose to the expansion valve connects to. The schreader connection at the top of the photo is for the high side pressure sensor. The next photos are the desiccant cup and filters from inside the drier assembly.






       

Here is what is inside the drier assembly. The orange plastic circle is the top lock for the filter and the desiccant beads that are inside the black cup, these all fit into the bottom of the drier assembly. The tube passes through the center of the cup so that liquid refrigerant that collects underneath the filter and desiccant cup is fed to the outlet of the drier and onto the expansion valve.

These are the felt filters that are at the top and bottom of the cup, their job is to hold the desiccant beads in the cup as well as be a filter for the system.

In order to make the sealant more visible I took the top filter screen and cut it in half and flipped part of it over. As you compare the picture above and this one, note the swirl pattern visible from the spaces in the orange lock disc, that's the top side. Then on the bottom side you will notice two colors, both a grey and spots of green. The green is the sealant that has crystalized in the felt.









The last two photos are of the expansion valve. There was no way to know if it was OK or not prior to disassembly other than to replace the drier, and then run and test the system. With the system already open it made more sense to simply plan and replace it which also allowed me to flush oil and sealant from the evaporator core as well.