[Engine] Missing water detection blanking plug - solved

[kerlaan]

Has anyone seen how the water detection sensor integrates with the fuel filter body please?

I am about to replace my fuel filter housing (it's in the post at moment, arriving tomorrow) and I noticed that the current housing is missing the blanking plug for the water detection sensor, item 8 at catcar fuel filter body.

I am replacing the housing because air is getting past the priming pump.  But I am now concerned about the water detection port and how it seals.  Could this also be part of my air ingress path currently?  To put it another way, will I need to ensure this port is blanked off when my new housing arrives (tomorrow)?

Thanks again for reading and thinking about this.

Happy New Year to all.

[Sol]

That is for the optional water detect sensor that never seems to be fitted to any diesel I've checked. The blanking plug will need to be there if the port is open. Normally on the later engines the socket for the plug is there with no pins, and the sensor is built into the housing if it was to be supplied. I'd make sure it's sealed on yours. The fact it can have a blanking plug and yours is missing, could actually be all that's wrong with the one you have.

[kerlaan]

That is for the optional water detect sensor that never seems to be fitted to any diesel I've checked. The blanking plug will need to be there if the port is open. Normally on the later engines the socket for the plug is there with no pins, and the sensor is built into the housing if it was to be supplied. I'd make sure it's sealed on yours. The fact it can have a blanking plug and yours is missing, could actually be all that's wrong with the one you have.

That makes sense Zion, but what is puzzling me is there is nothing leaking out from that area!!  Whether air is being drawn in I don't know.  It's all very counter intuitive.  I guess I'll find out what's what when I strip the housing off.  I'm hoping the new one arrives tomorrow; I hate waiting for parts.

[Sol]

Yeah may be nothing to do with it, I know on the later ones if there is no sensor, then there is no hole either. Could be your casing is cracked but the water trap still opens when you unscrew the bottom plug to let water or fuel out. Probably the air can get in that sensor port but no fuel out, as that plug hole for the sensor may be under negative pressure or diesel is too thick to fall out of it (very small hole?). Or it's at an angle or level internally that keeps fuel from getting out. Agreed it doesn't make sense really but who knows mate.

[kerlaan]

Yeah may be nothing to do with it, I know on the later ones if there is no sensor, then there is no hole either. Could be your casing is cracked but the water trap still opens when you unscrew the bottom plug to let water or fuel out. Probably the air can get in that sensor port but no fuel out, as that plug hole for the sensor may be under negative pressure or diesel is too thick to fall out of it (very small hole?). Or it's at an angle or level internally that keeps fuel from getting out. Agreed it doesn't make sense really but who knows mate.

I'll post what I find.  Mine is october 2000 production and so possibly the Purflux housing was being supplied without a drillway/passage/pressure tapping.  I suspect no hole but cannot see with the inspection mirror.  I need the little so-and-so in hand so to speak.  I suspect a hairline crack between the water trap and the port.  Your point about the diesel viscosity and conductance too as I think about it fits.  If there was a blanking plug it's somewhere on a roadside close to hell...

[saskak]

This is how the water in diesel sensor is attached: https://www.youtube.com/watch?v=-ZqiyCFg0sI
I upgraded mine. The hole for the sensor is plastic and closed off if you do not have the sensor. A new sensor breaks the plastic barrier and the two probes get in contact with the fuel. There is a valve on top of the filter for purging any water in the filter, the seal there could be damaged and some air getting inside, but I have never seen that before.

[kerlaan]

This is how the water in diesel sensor is attached: https://www.youtube.com/watch?v=-ZqiyCFg0sI
I upgraded mine. The hole for the sensor is plastic and closed off if you do not have the sensor. A new sensor breaks the plastic barrier and the two probes get in contact with the fuel. There is a valve on top of the filter for purging any water in the filter, the seal there could be damaged and some air getting inside, but I have never seen that before.

Thank you, I can sleep tonight saskak.  The fact that the sensor when installed would break the barrier is good news indeed and makes sense.

The valve on top of the body is leaking and why I have a new one on the way.  Not surprising the seal is failing after nearly 20 years and 200,000 miles...

[saskak]

Thank you, I can sleep tonight saskak.  The fact that the sensor when installed would break the barrier is good news indeed and makes sense.

The valve on top of the body is leaking and why I have a new one on the way.  Not surprising the seal is failing after nearly 20 years and 200,000 miles...

Do you mean that you had a fuel filter that lasted 20 years or 200k miles and it was never replaced? That was some quality fuel filter and probably equally good fuel was put in the car.

[Romahomepete]

On our M59 Berlingo we were getting air in at the top where the seal is. The clip that holds the 2 halves together was the culprit. A new clip tightened the 2 halves together with the O ring making a good seal. I chased this fault for months before solving it.

Peter

[Martinez]

On our M59 Berlingo we were getting air in at the top where the seal is.  The clip that holds the 2 halves together was the culprit.  A new clip tightened the 2 halves together with the O ring making a good seal.  I chased this fault for months before solving it.

Peter

I had air getting into my fuel filter. Replacing the seal fixed it