Fuel Fixers  Call
 Shopping Cart more
0 items
Shipping & Returns
Privacy Notice
Conditions of Use
 Articles more
Technical Info
Installs and Applications

FREE Priority shipping anywhere in USA!
including P.O. Boxes

Flat rate international priority shipping for $27

 Secure Shopping

PayPal Payments
No PayPal account required

R2D2-R2D1 Q&A


Gauge operation:

How does the gauge work? Inside the diesel proof, sealed gauge is a yellow diaphragm, much like a balloon. As vacuum increases inside the gauge the yellow diaphragm is pulled / sucked down. At various intervals it locks in position and is held there until reset. First locking position is 4” of mercury vacuum, Second is 6”, Third is 8.5” (bottom of green zone) Final is 10” of vacuum at the top of the Red Zone. Note: The yellow indicator / diaphragm inside the gauge may not be seen if the filter is clean.

How tough is the gauge ? The gauge is extremely durable. Its components are made up of a high quality Nylon, Diesel proof rubbers and Diesel proof sealants. All the materials stand up to severe impact and high heat. The gauge will function perfectly from - 40 degrees to over 250 degrees Fahrenheit. Every gauge and all of its components go through numerous inspections and must pass very high quality control standards.

Each and every T-handle gauge is Made in the U.S.A..

When should the filter be changed ? Change the filter when the yellow indicator is at the bottom of the green zone (8.5” of mercury vacuum). Half way down the green zone means the filter should be monitored closely. Do not wait until the gauge is near the red zone, the engine is being starved for fuel. It is not uncommon to get well over 500 hours use out of a Fuel Filter if the fuel is not contaminated and the fuel tanks are clean.

Why does the gauge show a contaminated filter when the filter was just changed ?

1) The reset was not pressed when the filter was changed.

2) The gauge is showing that there is a restriction before the filter. This could be a collapsed fuel line, a clogging fuel line, a restriction / gunk in or at the pick-up in the bottom of the fuel tank. This is another benefit to using the gauge. It will show any restriction in Fuel Flow from the filter back to the bottom of the fuel tank.

Hand Tight ? The T-handle should ONLY be hand tight. That DOES NOT mean as tight as you can get it by hand and it certainly does not mean use two hands. The 0-ring seals the T-handle to the lid and only needs to be snug. Over tightening the T-handle can damage both the 0-ring on the t-handle and the 0-ring inside the filter cover. 0-rings seal surprisingly easily, at very low torque and seldom loosen up.

Back Flow Preventer Valve:

How does it work ? Inside the T-handle is a valve which seals the unit if back pressure over 1 p.s.i. occurs. It prevents any chance of damage to the gauge when using a Filter priming pump, which are able to produce over 25 p.s.i.. The Back Flow Preventer valve is also designed as a safety mechanism to stop a Flow of Fuel out of the T-handle, if the gauge head is removed, broken, melted or destroyed. When vacuum / suction is reapplied (engine started) the Valve opens and allows the gauge to operate normally. The valve can handle pressure over 90 p.s.i..

Can Fuel enter the gauge ? YES… The gauge is designed to be able to fill with fuel. The gauges operation will not be affected in any way. In rare instances this can happen when the fuel levels and or fuel tanks are above the height of the top of the filter and the back pressure, due to gravity, is so little it does not trigger the Back Flow Preventer valve to engage. Again; the gauge is designed to handle this and it can be a normal occurrence in certain applications. When the engine is restarted the fuel in the gauge will be sucked back out of the gauge head. All components of the entire gauge are diesel proof.

Reset Button:

How Does it work ? The yellow button, located on the top of the gauge is the reset button. When pressed it releases a locking mechanism inside the gauge. It DOES NOT and never can open the gauge to the outside atmosphere. It DOES NOT release vacuum. When pressed It will allow the yellow diaphragm inside the gauge to return back to the top of the gauge, out of sight, at its zero setting.

Can the reset be pressed anytime ? YES….. But do not do it with the engine running, it will not reset due to the vacuum. There is No need to reset the gauge until the filter is changed. If the filter is not changed and the reset is pressed, the gauge will return to it’s previous position once the engine is restarted and run at operating speed.

Gauge will not reset while on the filter ? This is due to some form of back pressure which has triggered the Back Flow Preventer Valve. Everything is working as it should. Because the yellow diaphragm inside the gauge works much like a balloon, when it is expanded it will not “deflate” due to the vacuum contained within the gauge. Simply remove the T-handle gauge from the filter, wait a few minutes then press the reset button 3 to 4 times. This will allow time for the Back Flow Preventer valve to reset itself and then allow the gauge to reset also.


Can the 0-ring that comes with the new filter be used ? YES…. The 0-ring that comes with the gauge lasts longer than the replacement 0-ring which comes with the new filter, but either can be used without a problem.

© Fuel Fixers Inc. 6/2011

Products related to this article:
More info Buy Now
More info Buy Now
All content and Images Copyright © 2024 Fuel Fixers
Copyright © 2000 - 2024 osCmax
Powered by osCmax v2.5.4