infidel

A gauge is a gauge, doesn't matter what you put in it as long as it isn't acid or something else that isn't normally found on a vehicle.

Liquid filled gauges will slow down the pulsations on an electric pump such as a 24 valve and newer but the needle will still swing wildly with a mechanical lift pump that the 12 valves use.
For a 12 valve you have to use a snubber or needle valve or you won't be able to read the gauge in the short time before it self destructs.

Surplus Center's inventory changes all the time.
Sometimes they have Autometer Industrial gauges for under $10.
That's what I have on my trucks, even says fuel on them and were $6.99.

KATOOM

Are the schrader valve connectors for the OEM schrader test valve also available? I'm wondering if I should ditch the schrader test port I plumbed in and replace it with a stand alone gauge like you mentioned for reference.

carl48

the schrader valve is the freon 12 connector that is what i use on my test hose. i do not like to permanently connect a gauge to it. if you do not want to tap the bolt get a tapped bolt from genosgarage.com $7.50 i also bought some Stewart warner 0-16 psi gauges from surplus center for $6.99 and the needle valves for $2.99