Air conditioning expansion valve stuck?

[TomCat]

Short version:
I converted my 91 to 134a about 4-5 years ago.
This weekend a/c quits blowing cold.
I get some refill from auto store...charge it and it blows cold during the charging...shut it off.
An hour later not cold (so I figured I had a refrigerant leak)
Take it to a trusted independent (who normally works on my Nissan and is pretty good)
Independent says he evacuated the system and started to recharge and his gauges show the hi pressure side is 0 and the low pressure side fluctuates between 30 psi and 0...he says this suggests the expansion valve is not opening/working.
Independent said get a second opinion (from Acura or NSX expert) since repair/replace expansion valve is considerable (cost and labor).
Questions:
1) Is this a common failure mode?
2) Is there a flush that might un-gum the mechanism?
3) Any experience/suggestions?
Thanks

 

[bizlipkick]

Short version:
I converted my 91 to 134a about 4-5 years ago.
This weekend a/c quits blowing cold.
I get some refill from auto store...charge it and it blows cold during the charging...shut it off.
An hour later not cold (so I figured I had a refrigerant leak)
Take it to a trusted independent (who normally works on my Nissan and is pretty good)
Independent says he evacuated the system and started to recharge and his gauges show the hi pressure side is 0 and the low pressure side fluctuates between 30 psi and 0...he says this suggests the expansion valve is not opening/working.
Independent said get a second opinion (from Acura or NSX expert) since repair/replace expansion valve is considerable (cost and labor).
Questions:
1) Is this a common failure mode?
2) Is there a flush that might un-gum the mechanism?
3) Any experience/suggestions?
Thanks

Completely off topic, but is the expansion valve right angle or normal?

 

[Honcho]

The expansion valve is accessible from the front bay. You just need to remove the blower assembly. A good tech can access it in 15 minutes. No need to remove the interior/dash. That is only necessary if you are replacing the evaporator.

 

[TomCat]

The expansion valve is accessible from the front bay. You just need to remove the blower assembly. A good tech can access it in 15 minutes. No need to remove the interior/dash. That is only necessary if you are replacing the evaporator.

Fantastic!
New information...I picked it up last night (with no work done) and it blew pretty cold (especially out of the passenger side) for a few minutes.

Normally, colder from passenger side indicates low refrigerant...which is why I added in some in the first place a few weeks ago.

I'm now wondering if the valve is sticking intermittantly and a good/professional "flushing" will help???

 

[davidf]

Flushing is most benificial when you find small particals in your system, which is not usually a good sign anyway. Since you will opening the system anyways, I strongly recommend a new drier/accumulater, especially if it's original. Not terribly $$ and not to hard to replace.

 

[TomCat]

Flushing is most benificial when you find small particals in your system, which is not usually a good sign anyway. Since you will opening the system anyways, I strongly recommend a new drier/accumulater, especially if it's original. Not terribly $$ and not to hard to replace.

What is a good source for drier/accumulater and expansion valve, etc...

 

[davidf]

What is a good source for drier/accumulater and expansion valve, etc...

I went with OEM.

 

[davidf]

You might shoot these guys a PM.
http://nsxprime.com/forum/showthread.php?t=161937

 

[TomCat]

You might shoot these guys a PM.
http://nsxprime.com/forum/showthread.php?t=161937

Thanks!

 

[Honcho]

Don't get raped by OEM prices. Go here.

 

[TomCat]

Don't get raped by OEM prices. Go here.

Roger!

 

[TomCat]

Roger!

I blew pretty darn cold today...slightly colder on passenger side.

It seem/feels like some sensor or component is intermittant?

 

[TomCat]

The expansion valve is accessible from the front bay. You just need to remove the blower assembly. A good tech can access it in 15 minutes. No need to remove the interior/dash. That is only necessary if you are replacing the evaporator.

Acura dealer said it is confirmed a sticking expansion valve.
Quote was $1200 to do it...I guess I'll get the part and try it myself through the blower assembly...any good instructions/pictures of this technique?

 

[Honcho]

Acura dealer said it is confirmed a sticking expansion valve.
Quote was $1200 to do it...I guess I'll get the part and try it myself through the blower assembly...any good instructions/pictures of this technique?

If you go to the UK forum, member Kaz has a nice how-to thread with pictures. Kaz is the UK's LarryB. If I recall correctly, once you pull the blower off, you'll be staring right at the expansion valve. Now, getting a wrench in there to loosen the thing and remove? That might take a little while.

 

[TomCat]

If you go to the UK forum, member Kaz has a nice how-to thread with pictures. Kaz is the UK's LarryB. If I recall correctly, once you pull the blower off, you'll be staring right at the expansion valve. Now, getting a wrench in there to loosen the thing and remove? That might take a little while.

Fantastic...for $1,200 I can bust a lot of knuckles!

 

[TomCat]

Fantastic...for $1,200 I can bust a lot of knuckles!

Do I use teflon tape on the expansion valve threads?