The pricol gauge has a small screw with a small hole in the center. Obviusly you remove the screw to fill the gauge. Is the location of this screw important (the depth). Thanks for your input.

 

Nothing obvious about that......?

I have never seen or heard of a gauge being "filled". Just hook it up and roll, any air that is present will be replaced with fuel over time.

Trust me.

 

Instructions from the isolator said to fill the gauge. I thought it sounded weird. thaks for you help.

 

Are you taking about a liquid filled gauge? Where the movement and the dial are submerged in glycerin and you see it in the window? If so they are never completely full and they don't need to be serviced. The fluid dampens the movement and lubes the gear.

If you are trying to fill the gauge's bourden tube, where the pressurized fuel will be, then it's not needed. Pressure is pressure whether it is being exerted by a gas or by a liquid. Same reading. Some air is fine and it would be hard to completely remove it.

With an isolator you may need some liquid in the gauge line to prevent the diaphragm from bottoming and giving a low reading.

John

 

Uh oh. I didn't even consider you were running an isolator........

YES, you will need to fill the line between the isolator and the back of the gauge with antifreeze.

Sorry about that buddy, I ran my mouth too quick there.

 

As you have been told you do not fill the gage but the line between the isolator and the gage. Also as mentioned having air in the line is not the end of the world as it will also transmit the pressure signal to your gage. The difference with a filled line and just leaving it full of air is that air will slightly dampen the gage reaction and having the gage line filled with liquid will make it more reactive.

I used -30 degree F windshield washer fluid (mostly menthol) instead of anti freeze.

 

a big syringe will work well trying to get any liquid into that line

hope this helps

 

I don't pre-fill or bleed any of my mechanical pressure gauges so that the mixed liquid/gas column in the capillary tubing effectively isolates/dampens the notorious CTD harmonics - resulting in a steady needle position.

I have several underhood liquid-filled gauges, but the glycerin tends to leak out of them!