Gas gauge help

[Ricosan]

Hey Guys,

My gas gauge worked for a short time after installation but it failed right after I filled the tank for the first time. The red dye looks as if it exploded.

Yesterday I returned to my mechanic to get more red dye. He gave me the bottle and when I got home, I noticed it had a specific gravity of only .826. I’ve read here that 2.96 is what was originally used. Is the low specific gravity the reason for the failure or will I be safe with the .826?

Richard

[glennpm]

Hi Richard,


You need the heavier fluid. The lighter weight fluid will just go over the top of the tube like you experienced. This link explains more about the "why" of it.

https://www.fordbarn.com/forum/showp...3&postcount=20

Glenn

[glennpm]

The range from empty to the F, full mark of the gauge is 15/16".

The required high density fluid has a specific gravity of 2.95-2.96


The low density fluid you got (probably auto transmission fluid) has a specific gravity of .826. The light specific gravity fluid will raise 2.96/.826 X 15/16" = 3.36" !!


So yes it will flow out the top of the gauge glass tube.

[Ricosan]

Thanks for the link Glenn,

I’ve found the red dye at several different venders but none list the specific gravity. I’ve read good things on here about the red dye from Macs. Does it have a high sg or just good at not fading?

Richard

[glennpm]

You're welcome Richard,


Mac's is the high density type. I bought some a few years ago and it did fade a bit. I believe Mac's has stopped selling it.


Glenn

[Ricosan]

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I bought some of the red dye from Macs last year before they quit selling it. I gave it to my mechanic. He said it wouldn’t last and suggested we use his fluid. I would go over to get it today but his shop is about 25 miles from me.

Thanks for the help.

Richard

[glennpm]

Good plan!

[marko39]

The .826 fluid is used in manometers both incline and u-tube types.an example is the manometers that came on Sun Dist. testers.

[deuce_roadster]

Marko39 is correct, my Sun machine came to me with a bottle of Sun manometer fluid.

[glennpm]

Yes if a manometer is designed for the lighter specific gravity fluid it would be proper. It is not the correct fluid for the Ford gas gauge manometers. They require the 2.95-2.96 fluid.

[deuce_roadster]

I have a bottle of Ford gauge fluid from a Ford dealer back in the 40s. It is still as red as the day it was made.

[Karl]

Originally Posted by deuce_roadster

I have a bottle of Ford gauge fluid from a Ford dealer back in the 40s. It is still as red as the day it was made.

Ditto

Karl

[Ricosan]

I am driving over to my mechanics shop right after breakfast to exchange the .826 for the Macs red dye. I don’t know what the sf is for the Macs. Maybe it will be on the bottle.

Richard