Do AC expansion valves get clogged like orifice tubes do?

[Bonnewagon]

Not a G-body, but a 1995 Firebird LT1. AC has good pressure at rest but instead of low side dropping to operating pressure, it goes up to high side pressure range when compressor is on. This model has an expansion valve in front of the evaporator with both lines passing through it. I was wondering if the valve could clog up like orifice tubes do and cause this. I haven't seen one of these since the 60's and I am completely at a loss here. It looks like this-

and it is located here. What does the disc on top do? F-body guys please help me out here.

 

[DRIVEN]

Re: Do AC expansion valves get clogged like orifice tubes do

They don't normally get "clogged" but can get sticky (like a failing thermostat in your engine). It's usually a result of moisture in the system. It acts like a temperature controlled spool valve. The disk is part of the thermostatic portion, I believe.

 

[Bonnewagon]

Re: Do AC expansion valves get clogged like orifice tubes do

So, instead of a metered hole (orifice), the disc on top moves a valve inside that block? I don't suppose it's worth my while to remove it and see if it can be cleaned. As long as I have to evacuate the system, I guess I should just get a new one.

 

[DRIVEN]

Re: Do AC expansion valves get clogged like orifice tubes do

Quick learner 😀 .

 

[tc1959]

Re: Do AC expansion valves get clogged like orifice tubes do

So, instead of a metered hole (orifice), the disc on top moves a valve inside that block? I don't suppose it's worth my while to remove it and see if it can be cleaned. As long as I have to evacuate the system, I guess I should just get a new one.

Yea the blocks are one piece ,the old school expansion valve had a small inlet screen, but alas no more.
You just have to replace the block. Man I miss the simple CCOT system. 😢

 

[Bonnewagon]

Re: Do AC expansion valves get clogged like orifice tubes do

I am so used to the orifice tube system that I'm clueless here. I never worked on AC in the old days, I was scared of it. Now it's just another skill, but this one has me stumped. My only conclusion was that the valve was clogged and causing the low side to hold way too much pressure. There's really nothing else in the system to get blocked. Now I have to convince my Kid to spend $30 on a part that "might" fix it, easier said than done.

 

[Blake442]

Re: Do AC expansion valves get clogged like orifice tubes do

Just tell your daughter you can't fix it.
Then, without a/c, maybe she'll finally break down and sell it... :lol:

 

[Bonnewagon]

Re: Do AC expansion valves get clogged like orifice tubes do

SSSHHH! It's on Epay right now! Keeping fingers crossed.http://cgi.ebay.com/ebaymotors/Pont...de2QQitemZ250862882274QQptZUSQ5fCarsQ5fTrucks

 

[tc1959]

Re: Do AC expansion valves get clogged like orifice tubes do

SSSHHH! It's on Epay right now! Keeping fingers crossed.http://cgi.ebay.com/ebaymotors/Pont...de2QQitemZ250862882274QQptZUSQ5fCarsQ5fTrucks

I will buy it if you fix the AC :shock:

 

[Bonnewagon]

Re: Do AC expansion valves get clogged like orifice tubes do

If you buy it, I'll deliver it to Arizona! :shock: