What is an airlocked - Cars & Trucks

I wrote this tip on getting rid of airlocks.

https://www.fixya.com/cars/r29872074-vehicle_cooling_system_no_heat

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You will have an airlock in the fuel system..........bleed the airlock out and it will fire up!

please say what is air lock,
was this a guess?
or a test that failed, what?

airlock?...its suppose to have a vacuum to draw out the fumes to send through your charcoal canister which could be clogged...leave gas cap half loose...

check that the air bleed hose from the top of the tank up to the filler neck is not pinched ,squashed or blocked as it is apparently not letting the air to come out while the fuel is going in.

looks like heater hose

Unlock an airlock??? Please explain.

remove thermostat and drill a small hole in it to allow the air to come up to header tank

could be start of head gasket problem

Hello, I see that you are having a fuel problem on your 99 Sierra. It sounds as if the fuel pump screen has a restiction on the screen causing it not to be able to pull fresh fuel. Instead it is running out of fuel inside the fuel pump module and it will then start sucking in air. Since you will have to remove the fuel pump module if it has 100-150,000 miles on the fuel pump module you may want to just replace it, because that is about the average life span under normal conditions.