Car AC problem/symptom and question

[squonk 47,318]

1 hour ago, Blaine said:

I’ve seen the air side clogged, with about 2 pounds of dog hair… 

Leaves, twigs, nuts, dog food! 

[CasaytheMann 172]

I'm curious as to how they determined the evap coil was clogged??

Once low side refrigerant is blocked, or restricted, suction pressure drops. Once suction pressure drops, there is not as much refrigerant for the compressor to pump, and the high side pressure drops too.

[adsm08 4,771]

1 hour ago, Blaine said:

I’m still struggling to understand how anything would get inside the evaporator to clog it. 
 

 I just threw about 813 silica beads at this expansion valve and not one of them made it through. 
 

 

Those are much larger than what is found in AC desiccant bags. The particle size is closer to sand.

 

I have also flushed a fair amount of sand out of cooling systems in the last few years too.

Edited 10 hours ago by adsm08

[Beap52 2,341]

It was the 4th compressor before we accepted and installed it on my pickup.  The man who does my AC work dumps the oil out of the compressor so he can be assured it's correct.  Two of the compressors had metal filings in them, one had already been opened (and possible installed due to dirt on fittings) He wasn't going to accept a compressor sitting unsealed on a shelf.  Finally the 4th  was acceptable to him but now, a couple of seasons later, it's clutch sounds loud to me.  These came from a local parts house. 

 

I would think with the technology and machining abilities now available that even overseas production would result in better parts. 

 

 

[adsm08 4,771]

9 minutes ago, Beap52 said:

I would think with the technology and machining abilities now available that even overseas production would result in better parts. 

 

It doesn't matter how good the tech is if you give it to a 5 year old and pay them 10 cents a day.

[Blaine 194]

They are from an A/C desiccant bag. 
 

i have a 2008 Edge with the 3.5L v6 in my bay right now for a power steering pump. I took these pictures of the expansion valve location. If you look at that area you should be able to see witness marks around the vicinity to know if they actually swapped it out. That nut should have fresh socket marks on it. 

 

 I don’t recall replacing one specifically on an Edge, but it’s deep in there, but it looks doable from the firewall side. Removing the plenum would make a lot more access room. 
 

 

[adsm08 4,771]

13 minutes ago, Blaine said:

I don’t recall replacing one specifically on an Edge, but it’s deep in there, but it looks doable from the firewall side.

 

It is. Pull the intake and you have more room than you know what to do with.

 

All the known drier failures I have ever seen put a sand-like material through the system.

Edited 9 hours ago by adsm08

[adsm08 4,771]

2 hours ago, CasaytheMann said:

 

Once low side refrigerant is blocked, or restricted, suction pressure drops. Once suction pressure drops, there is not as much refrigerant for the compressor to pump, and the high side pressure drops too.

 

No, not quite.

 

You are correct up to the very last part. Once all the refrigerant is stuck on the high side, between the compressor and the restriction the high side pressure has exceeded the safety limit and if it doesn't blow of the safety release the computer shuts the compressor off. The pressure at that time is usually between 350 and 400 PSI.

Edited 9 hours ago by adsm08

[wh500special 2,424]

I didn’t ask for a ton of detail when I spoke with the shop, but what I remember he told me was that they initially ran the car and checked pressures.  Was very high on high side with compressor running and very low on low side.   And the pressure switch would then shut it down.  I saw the same thing at home a while ago but it was much cooler and apparently it was a little less clogged at the time and was still circulating a little.  It had gone to nothing since.
 

He suspected either a bad valve ( which I asked him to go ahead and replace since it was cheapish) or something blocking flow in evaporator. 
 

talked to him later in day and they had cracked it open and took out old valve.  I don’t remember what else. Indicated that they tried to blow compressed air through evaporator and not much was getting through and that some gunk and dye was coming out. They were going to tinker with it a bit and see what happened. 
 

later they called and asked if I needed the car back right away.  I didn’t.  They’d gotten stuff out of the evaporator thought it was probably still clogged at least somewhat and were going to let it hang on vacuum a few hours in the morning then put gas back in it.  He didn’t seem optimistic, but they needed to close it up anyway so it didn’t hurt to try.  
 

next day they did a what they said, found it still didn’t work (no huge surprise but I was hoping…) and asked if I wanted to go further. I don’t.  He said the book says it’s 6 hours to remove the dashboard and thought it probably takes every bit of that at least. 
 

I mentioned the dessicant filter rupturing and he said, “yep.”

 

this is a great shop. Full confidence in just dropping off a car and having them do their thing.  They mostly work on Mercedes, BMW, Audi, and VW but not exclusively.   They spent a lot of extra time dinking around on my air conditioner and only charged me about $300.  Plus the axle shaft job ftom one of those speed sensor rings that broke and lit the ABS lamp.  
 

I would have ignored it, but the pedal was pulsing on almost every stop so it needed to be done.   Now I just wait for the other side to break.  
 

There are other takeaways here of course, but a notable one is that @adsm08 is our resident Ford go-to.   A while back I recall him commenting about some weird split fuel sender issue on a Ford that had befuddled mechanics.   
 

Thanks for all the input!

Steve