Coolant reservoir bleeder valve clogged?

[xmac]

I noticed that when my engine has been warmed up, the bleeder valve on the coolant reservoir pushes outward and does not seem to relieve pressure. The metal latch is floating above the point where you would normally bring it up to "lock" it in place to bleed air out after maintenance. I carefully cracked open the reservoir coolant cap which let lots of air out and the bleeder valve immediately moved back down. The tank was replaced in 2003 so it is not the original.

Questions:

1. Isn't the bleeder valve supposed to automatically allow air out even when not locked in the up position?

2. If so, any idea where the bleed point is to see if I can unclog it?

I realize I have the option of replacing the bleeder valve only for $80 for a new valve. Looking at it though, it would be almost the same amount of work to replace the valve as it would be the whole tank. Clearly, the tank is holding pressure and not leaking. I attached a closeup of Boxster valve just for illustrative purposes.

[logray]

Once the pressure increases in the cooling system, the bleeder valve opens all on it's own. By design. Then it closes again once it cools down.

The metal latch is designed so you can bleed a cold system.

[xmac]

Sorry I didn't clarify in the original post. The problem is that the plunger is pushing significantly beyond where the metal latch would hold it "open" and not letting anything out.

For example, if the metal latch normally pulls the plunger up by 1/4", the problem I am seeing is that the plunger by itself is pushing out 1/2" and still not relieving pressure. If I crack open the radiator cap, the pressure drops and the plunger goes back down to the normal down position.