03’ 9900i air in fuel

[Redland1]

I wanted to see if I had air in the trucks fuel and a mechanic friend let me borrow a sight glass and I put it on just before the fuel enters the fuel/water seperator.Sure enough I got a bunch of little bubbles.What kind of problems will this cause or does the air get removed at the pump?

[Rawze]

Tiny bubbles like that could just be cavitation .. but it could be sucking air somewhere too...

You could pressurize the fuel tanks to 10 psi and let it sit for a couple hours. See if there is any fuel leaks in the lines leading to the engine. Just don't try to remove the fuel caps while any air is pressure is applied on the tanks.. as it could break your hand/arm.

[Redland1]

(07-14-2023 )Rawze Wrote:  Tiny bubbles like that could just be cavitation .. but it could be sucking air somewhere too...

You could pressurize the fuel tanks to 10 psi and let it sit for a couple hours. See if there is any fuel leaks in the lines leading to the engine. Just don't try to remove the fuel caps while any air is pressure is applied on the tanks.. as it could break your hand/arm.

Would the breather hose be the best place to air the tank up or is there a better way to do it?

[Bengy88]

The breather hose is pretty much the only way to check what you’re checking for. For real though listen to Rawze about not pulling the cap till the pressure is released. It will literally f*** you up. Also be sure to turn your regulator all the way down before you hook it up.