Changed the fuel filter and o ring in my 2l tdi skoda yeti yesterday.

Didn't fill the fuel filter housing after replacing the filter and primed with the ignition 8 times for 15 seconds rather than vcds prime.

Initially started I reversed 1 meter, it cut out and won't start now.

Checked the seal and it seems ok, hex bolts are down tight. The filter housing is full of diesel so not thinking of lift pump

When I turn the ignition on, the pumps runs quiet for 3–5 seconds, then whines for 3-5 seconds, then returns to normal and stays quiet indefinitely

It will do this indefinitely if I keep turning the ignition on and off.

My bit of research points towards intermittent air ingress in the feed line from the tank rather than o ring given intermittent whine?

Could anyone tell me which line is which? I'm assuming yellow and blue and the high powered line and return and that the green and red are feed line and return from diesel tank?

Interested in any other opinions while I wait for the mechanic to take a look!

Mechanic sorted it. Was airlocked so he opened it at the injectors.