Blue release valve? As far as I know the stock valve covers were
black. If you have a quick disconnect at that blue release valve, it
is entirely possibly someone converted it to R134A before.
However...You need to be sure. The oils use by the stock system for
R12 are not compatible with the oils use with R134a.

To do a conversion, the system is usually flushed (with an alcohol)
and the reciever/dryer replaced, as well as the quick disconnects (on
high and low side...blue being low, red being the high side.)

If your system was previously using R134A you can recharge it
yourself, though I find it a pain as the R134A takes a while to get
sucked into the system.

On Jun 11, 2006, at 11:10 PM, robertmstewart wrote:

>
> I have an 88 Auto Vanagon, the AC just blows air but does not get
> cold at
> all. By accident when I first got the van I opened the blue release
> valve
> connected to the compressor in the engine thinking that is was a
> way to
> bleed the coolant system, stupid me.