VDO fuel level sensors - fixable?

[Durcott]

Evening all. I've got a pair of VDO tube style fuel sensors. I'd guess circa 20 years old. One of them is reading eratically. A few taps around the head proves it's the sensor, not the panel meter.

Fortunately there's a back up dip stick.

I'm guessing these aren't fixable, but I thought I'd ask.

More to the point - replace both of them, or is it rare that these things play up?

Thanks for any comment as always.

Jeff

 

[snowbird30ds]

If a tap fixes a tube type sensor I'd say it's got crud in it, they are normally just a floating magnet around a tube full of reed switches with a resistor ladder between.
If the sensor is crudded worry about what is going through the filters and going to stop the engine at the most inappropriate moment.

 

[Momac]

Why replace both if only one is faulty ?
I had the same issue except with the float type sender and replaced the faulty sender.
That was just over a year ago.
The original sender in the other tank seems to still be okay.

However a good point is made in the post above. The first step would be to remove the sender for inspection.

 

[vas]

+1 on previous posters points.
granted have only removed and cleaned such sensors from water tanks, but slippery diesel managing to block the movement of the float sounds dangerous.
Unless float has started disintegrating and sticking around the tube (seen that on petrol though in a jetski tank)
and don't forget if you decide to replace to get the "right" type there's the European and US type of sender don't remember Ohm values of the top of my head though.

V.

 

[Gustywinds]

If a tap fixes a tube type sensor I'd say it's got crud in it, they are normally just a floating magnet around a tube full of reed switches with a resistor ladder between.
If the sensor is crudded worry about what is going through the filters and going to stop the engine at the most inappropriate moment.

Ah, I wondered about that. I’ve been looking at hooking up my tank sensors to my Victron system so I can read them remotely and had confirmed they are resistive ( which it needs) but seemed not to be linear, going up in jumps as you would see from an LVDT or digital sensor

 

[Durcott]

If a tap fixes a tube type sensor I'd say it's got crud in it, they are normally just a floating magnet around a tube full of reed switches with a resistor ladder between.
If the sensor is crudded worry about what is going through the filters and going to stop the engine at the most inappropriate moment.

Oh dear. You got it spot on. I took it out - filthy. So much for the vendor's assurances of clean tanks!!!

 

[Momac]

It could be worth removing the sender from the other tank also (assuming no other inspection hatch is provided). Just to hopefully rule out contamination in both tanks.

 

[vas]

Oh dear. You got it spot on. I took it out - filthy. So much for the vendor's assurances of clean tanks!!!

are your primary diesel filters clean?
maybe time to treat your tanks...