I though I\'d finally got to the bottom of a long running problem on my 2004 defender, these were the symptoms.
It ran absolutely fine for the first 3/4 of a tank but then failed as if it had run dry, pump gurgling. this started 12 months ago. I replaced the air vent valve in the filter block.
Then I had to park on the flat or with the nose down, otherwise it wouldn't start. this started 6 months ago.
Then 2 weeks ago it got air in the fuel line with a nearly full tank and had to be towed home.
So I replaced the fuel pump/sender unit with a VDO and new short hosed to the filter.
It was good for 2 days then failed again.
Today I pulled the injectors to replace the copper washers and seals. one of the washers looked suspiciously like it had been passing. Fired it up no problem but still a noisy pump gurgling. then it stalled again.
no amount of venting on the first click of ignition would clear it, even at the green hose at the back of the engine.
Then I removed the red return hose on the fuel cooler and ran the pump. Once reconnected the gurgling cleared, pump now quiet, runs fine.
So I guess, the issue was my injector copper washer, and that the fuel cooler need to be vented because it won't clear itself.
UPDATE. Next day it let me down again...

Not sure why it would be ok for 3/4 of a tank and then cause trouble if this is the only issue. I hope you have fixed the issue permanently but it doesn't quite make sense to me.

headintheclouds said:

Not sure why it would be ok for 3/4 of a tank and then cause trouble if this is the only issue. I hope you have fixed the issue permanently but it doesn't quite make sense to me.

Click to expand...

Damn it. It died again today.
Fuel pump is screaming. Definitely runs longer with the tank full.
could it be the pressure regulator? Or the filter?

Hopefully some closure here and assistance for anyone searching air in fuel system.
The old Male KC80 filter wouldn't drain or vent, guess it was blocked, new filter does both profusely. Possibly the noise from the pump was the second stage (HP) cavitating as it was starved of LP feed and gassing up. Anyway it seems to be running fine now. I fitted a new duckbill in the LP feed too as the old one couldn't shut its beak properly.
Thanks for your input everyone

Mudstyler said:

Hopefully some closure here and assistance for anyone searching air in fuel system.
The old Male KC80 filter wouldn't drain or vent, guess it was blocked, new filter does both profusely. Possibly the noise from the pump was the second stage (HP) cavitating as it was starved of LP feed and gassing up. Anyway it seems to be running fine now. I fitted a new duckbill in the LP feed too as the old one couldn't shut its beak properly.
Thanks for your input everyone

Click to expand...

Pleased you're sorted great news.
Tim