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Posted: 6/29/2012 12:26:35 PM EDT
so my AC isn't working right.  Hooked it up to the machine and the high and low pressure are normal until the compressor clutch kicks in .  At that point the low side gauge reads a vacuum then the vacuum increases with higher rpms



One of the body techs told me to change the expansion valve and the filter in the AC line.    



Anyone know for sure what the fuck?
Link Posted: 6/29/2012 12:29:44 PM EDT
I'm no A/C expert, but that's where I'd start too.
Link Posted: 6/29/2012 12:31:35 PM EDT
Sounds like the expansion valve to me.  I used to hit the one in my Mercedes from time to time with a torch,  heat it up enough to do it's thing.  In my case I had it replaced after a while.  

I's sure a hvac tech could give you more help than me though.  
Link Posted: 6/29/2012 12:41:25 PM EDT
OP, wasn't your vehicle having overheatting issues? I thought it was you?
Link Posted: 6/29/2012 12:54:21 PM EDT




Quoted:

OP, wasn't your vehicle having overheatting issues? I thought it was you?




yeah this is a seperate issue though.



no ac leaks . vacuum test was good.  just having no cold air.
Link Posted: 6/29/2012 1:07:52 PM EDT
Yeah, vacuum on the low side isn't right.  Should be 35-45 psi generally.

Change the valve & filter (if you have one), pull a vacuum on the system, and recharge.  As long as you're in there, not a bad idea to do the accumulator / drier as well.
Link Posted: 6/29/2012 1:22:00 PM EDT
expansion valve/orifice tube.

Link Posted: 6/29/2012 1:30:01 PM EDT




Quoted:

Yeah, vacuum on the low side isn't right. Should be 35-45 psi generally.



Change the valve & filter (if you have one), pull a vacuum on the system, and recharge. As long as you're in there, not a bad idea to do the accumulator / drier as well.




Should I pull the compressor and check for contamination or anything? What would cause this to clog up if it is the filter? Or should I not worry about it since there is no leak and compressor seems to be working fine.
Link Posted: 6/29/2012 1:30:20 PM EDT
Tag
 
Link Posted: 6/29/2012 1:34:15 PM EDT


xpansion valves do go bad. Do you see ice built up any where on the lines.
What car are we talking about?


Link Posted: 6/29/2012 1:37:52 PM EDT
Will presume your high side is spiking up to 300ish+ as well with the low side vacuum, and perhaps your exp. valve is coated in frost/ice cube?

Humor me too, will presume when you said normal pressures without comp. running, you meant 70-90 psi on both sides.  Will also presume you sucked out about 2 lbs, and put back in teh recommended charge.
Link Posted: 6/29/2012 1:42:36 PM EDT
info about the make and model might help.

i worked on a 2006 taurus that had this issue. running pressure were 35 and about 270. no cold air. no ice over. replaced $2.99 orifice tube and all was good.
Link Posted: 6/29/2012 1:51:36 PM EDT




Quoted:

Will presume your high side is spiking up to 300ish+ as well with the low side vacuum, and perhaps your exp. valve is coated in frost/ice cube?



Humor me too, will presume when you said normal pressures without comp. running, you meant 70-90 psi on both sides. Will also presume you sucked out about 2 lbs, and put back in teh recommended charge.




high side is staying around 200  low side around 40.  When ac clutch kicks in high side  goes a little higher but low side goes negative.  Vacuunm increases on low side with throttle.    



Couldn't tell if expansion valve is cold. It is in the  evaporator box under the dash. Haven't fucked with it yet.    



When we emptied the system it was at 24 ounces as recomended on the sticker under the hood .
Link Posted: 6/29/2012 1:52:06 PM EDT




Quoted:

info about the make and model might help.



i worked on a 2006 taurus that had this issue. running pressure were 35 and about 270. no cold air. no ice over. replaced $2.99 orifice tube and all was good.




2001 crv
Link Posted: 6/29/2012 2:01:02 PM EDT
typically, if you touch the accumulator/drier, it will be cold if the orifice tube is working properly.

receiver/drier looks like this:

Link Posted: 6/29/2012 2:22:07 PM EDT
Link Posted: 6/29/2012 4:22:08 PM EDT
I have seen more than one Honda and a few other cars do this. The desiccant bag in the dryer comes apart and plugs the system.



You will have to flush the evap core and lines and I suggest replacing the condenser because you wont get it all out.



It may just be the expansion valve but I don't think so.


 
Link Posted: 6/29/2012 4:44:18 PM EDT
Without the clutch angaged the pressure on the low and high side should be equal. if the high side is 200 and the low side is 40...and then the low side goes under 0 psi, you have a restriction on the low side of the system. Sounds like it's plugged pretty solid too.
Link Posted: 6/29/2012 6:00:11 PM EDT
Did you get the overheating issue fixed ?
Link Posted: 6/29/2012 11:25:44 PM EDT



Quoted:


Did you get the overheating issue fixed ?


not sure. it has been a couple days since it overheated after the last bleeding but is only did it with AC on and since the AC doesn't work there is no reason to run it.   Ill get back to that after teh AC works.



 
Link Posted: 6/29/2012 11:38:33 PM EDT
Not AC expert by any means of the imagination or stretch thereof.

However, sounds like a severe restriction if the compressor is able to pull a vacuum on the low side. I would say the restriction is at or after the exp valve/ otube. Being as its not cooling.

I have a date this weekend with my daughters truck and replacing the compressor , dryer, o tube and the hoses. May just replace the condesor too sense its a year shy of 20 YO.

Gonna be a fun weekend for sure.
Link Posted: 6/29/2012 11:52:58 PM EDT
Sounds like the desiccant bag ruptured, and you now have a severely clogged system.
Link Posted: 6/30/2012 11:17:19 PM EDT
just finished replacing the valve and dryer. checked compressor too.  doesn't appear to be wearing out. no metal sludge or anything.  Hopefully the valve was just fuckered up.  Charge on monday at work and see what happens.



replacing that valve on the crv was amotherfucker.  had to take the whole dash apart to get the blower and evaporator out to change that thing.


 
Link Posted: 7/3/2012 6:37:25 AM EDT
problem solved . It was the valve.
Link Posted: 7/3/2012 8:33:11 AM EDT
Luckyyyy
 
Link Posted: 7/3/2012 10:33:50 AM EDT




Quoted:

Luckyyyy




no shit. no metal contamination either so I think the compressor will last a while longer.
Link Posted: 7/3/2012 10:45:13 AM EDT
Quoted:

Quoted:
Did you get the overheating issue fixed ?

not sure. it has been a couple days since it overheated after the last bleeding but is only did it with AC on and since the AC doesn't work there is no reason to run it.   Ill get back to that after teh AC works.
 


I'm thinking both concerns may be overlapping issues?
Link Posted: 7/3/2012 11:49:47 PM EDT



Quoted:



Quoted:




Quoted:

Did you get the overheating issue fixed ?


not sure. it has been a couple days since it overheated after the last bleeding but is only did it with AC on and since the AC doesn't work there is no reason to run it.   Ill get back to that after teh AC works.

 




I'm thinking both concerns may be overlapping issues?


possibly. hard to tell.  My car hasn't overheated since I discharged the AC and since I fixed it.  Can't really say if that was contributing to it somehow though because I did do another bleed the day before the air stopped.  



All I know is the AC is cold and the thing isn't overheating.



 
Link Posted: 7/4/2012 12:06:38 AM EDT
Hopefully it stay that way!
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