Air in fuel line on 2011 Citroën C5 (X7) Comfort, 2-litre turbo

Orion

New member
Tadpole
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Jan 23, 2021
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Location
South Morang, Victoria
I see air in fuel line from time to time. Specially it seems to happen after driving on a hot day. The next morning, if I check it again, no air. No problem starting engine. Is it normal?

I have recently bought the car and changed fuel filter by myself. I am not sure if I have messed up something during the process. After changing the fuel filter, I fully tighten water bleeding screw and this caused air to get in. I noticed this because when priming fuel, fuel come out through fuel drain horse. So I loose it a quarter turn as shown in the image. This resolved the issue. Is it the right position of the screw?
 

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The water drain should be shut. Have you bled the filter? The RHH motor has a bleed screw on top. The HP pump can pump out any small remainder and the engine will start.
 
So there is something wrong with mine. Yes, I bled air in the fuel housing with opening bleed screw, but still see some air in fuel line sometimes. Ideally there shouldn't be air in fuel line, is it?
 
Are you talking about the 20 mm length of clear tube on the right side in the HP pump inlet line? A few little bubbles are removed by the pump and it starts. The RHH motor pumps up from the tank.
 
Cannot give you any 'Citroen-specific' advice but generally with the modern "common rail" diesels a little bit of air in the line doesn't seem to worry them. When I first got my Ute (secondhand) I was chasing a problem where there was an intermittent (but huge) "flat spot." Convinced myself it had to be a fuel feed issue and went as far as removing the tank & checking the pickup filter. I noticed the connectors line to tank were "quick release" placcy jobs & when I'd put it all back I bled the air using the screw on top of the filter. Next day there was air again, decided there must be an airleak at the line to tank coupling so pulled these off again & gobbed them up thoroughly with fuelproof sealant. Next day -you guessed it - more air. Monitored for several days & air always appeared in the morning before starting. Gave up trying to fix the thing myself & sent it to my local mechanicien {& fessed up to what I'd done}. He was unconcerned with my reports of omnipresent air - rightly as it turned out since the issue was the EGR valve actuator.
Regards,
Rob
 
Just went through this with the C5... I wonder if there's some diesel out there with volatiles or not enough anti-foaming?
 
Often the O ring In filter housing can cause it to suck air.

Need to fit quality filter like purflux or hengst and apply little grease to O ring when U fit.
 
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