C5 X7 air bubbles in fuel line with engine stalling

[xf1ref]

Hi All,

Engine (2.0 hdi RHH) is stalling seconds after turning on, the fuel line is full of air bubbles and I have to prime almost each day.
Has anyone changed the o-rings from fuel line connectors? The problem is somewhere on filter housing and connectors because before filter housing there are no bubbles.
Cheers!

[admiral51]

Will look for Peter N posts as he has had similar issues, give me a few minutes

Cannot find it, maybe i am not searching correctly but there is a thread that Peter N has had similar issues.

Hopefully someone will be along to point you in the right direction.

Sorry for not helping right away

Colin

[KennyW]

Have you changed your fuel filter recently, replaced with new rubber seal and tightened down the torx screws to correct settings has this is important as over doing this allows air to enter the fuel system. There are o rings on the fuellines entering and leaving the fuel filter. The smallest hole in the system allows air in.

Check all these areas for damage etc perished hoses.

My reason is I had a similar leak and I ended up changing the fuel filter housing as the the thread in one of the torx screws was knackered. Unable to tighten down correctly allowing air in.

Kenny

[xf1ref]

Thanks all for answers.
Changed the fuel filter this summer but nothing till winter came. Seems that the phenomenon is happening only when the outside temperature drops below freezing.
Air bubbles I have seen from the moment I brought the car but no issue till this winter. I have checked and greased all the o-rings from fuel lines and filter housing but no leak.
Could be something else like a return valve on the fuel line or priming pump?
Here is the video with the air bubbles from the line after the filter housing.

[xf1ref]

I changed the priming pump and now the engine start fine. Seems that one of one way valve was leaking and due to small vacuum from the tank the fuel was sucked back.
The bubbles are still there and already changed the o-rings on bleeding and draining ventil but no change.The original o-rings are blue color and a little more thicker than the new ones but couldn't find any code for these, only changing the hole filter housing. The next step is to change the o-rings on quick release connectors.

[xf1ref]

I had issues with air on the fuel line, no bubbles befor filter but a lot of bubbles after and some foam formed by excessive air. After changing the filter housing without any noticeable result I checked the o-rings from the line between filter and hp pump and surprise in the picture attached. Grase the connectors every time when changing the filter.

[MattBLancs]

Thanks for feeding back your solution. Given that O-ring is one inside a quick connector, and such small damage - it's no wonder you had such an issue getting to the bottom of this problem!

As you say, the fact that some quick connectors are part of the fuel pipework and others part of the filter means all are disturbed with each filter replacement but only some replaced each time!

If you have the size details of the O rings you used, please could you post them up for future reference?

Thanks,

Matt

[xf1ref]

Sure Matt, I have the sizes of the o-rings measured with calipers.
On each female quick connector, no matter if on filter housing or fuel line, there are two o-rings: one yellow and one green. The only difference is that on fuel lines between o-rings there is a brass or copper shim.
Dimensions for both
Cross section 2 mm
Outer diameter 13.5 mm

The cross section for the yellow one seems a little thicker like 2.1 or 2.2 but is very soft and I can't provide the real size.
Also the colour could indicate the material from which is made.

[MattBLancs]

Sure Matt, I have the sizes of the o-rings measured with calipers.
On each female quick connector, no matter if on filter housing or fuel line, there are two o-rings: one yellow and one green. The only difference is that on fuel lines between o-rings there is a brass or copper shim.
Dimensions for both
Cross section 2 mm
Outer diameter 13.5 mm

The cross section for the yellow one seems a little thicker like 2.1 or 2.2 but is very soft and I can't provide the real size.
Also the colour could indicate the material from which is made.

Spot on, thank you

[MattBLancs]

Had a quick dig (simplybearings website)

Seems they define the O-ring sizes as section and inside diameter, so a quick bit of maths has that as 2mm X 9.5mm I.D.

On that site, next up from 2mm section is 2.4mm so would seem a good candidate for the squidgy yellow one's section. Obviously hard to measure a squidgy thing! so unsure if was same O.D. ( nearest match is 13.4mm OD, 2.4mm section hence 8.6mm I.D.)

Keeping same/similar inside diameter, 9.6mm i.d. and 2.4mm section - but then we are 14.4mm OD, best part of a millimetre larger, which would be obvious by eye, regardless of the squidginess.

Green tends to be Hydrogenated Nitrile = HNBR but don't think a specific material associated with yellow.

Chemical compatibility information from Simply Bearings site of interest too:

Chemical compatibility - diesel

Chemical compatibility - petrol

This suggests "cheapo" NBR black O-rings would be fine in this application. Interesting HNBR isn't tabulated?

[MattBLancs]

https://www.globaloring.com/oring-colors/

Here suggests yellow could be NBR or Viton or they can supply anything in any colour....

[kk13171759588]

Buy a 9674087080 repair kit (costing a few to over ten dollars) and replace the seal at the filter outlet. This will usually completely solve the problem of manually pumping oil and shutting off the engine every day.
https://oilseal-china.com/o-rings/

[EdjKa]

Buy a 9674087080 repair kit (costing a few to over ten dollars) and replace the seal at the filter outlet. This will usually completely solve the problem of manually pumping oil and shutting off the engine every day.
https://oilseal-china.com/o-rings/

Is it legit kit number? Can't find any with that part number