fuel filter how to change

[A2Z]

Did you replace the seal in the filter housing lid? The slight gap is not really an issue and only use diesel to lubricate the seal. Pauls drain plug is far better and will out live the car..
When my filter heatshield was ripped off the car when hitting hidden flood water I glued large headed studs after cutting off the remains of the originals and used plastic nuts to secure the heatshied. A couple of washers were used where the holes had ripped through.

These are the studs that I used....

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Yes, I replaced all 3 seals, the two on the 10mm water drain plug and the big tapered seal on the threaded filter housing screw lid and i lubricated all 3 with diesel.
The small plastic drain plug went back in fine but the main filter housing thread felt tight to undo and tighten back up again.
I did thoroughly clean both the housing and lid when the old filter was removed and just feel both threads need a little more lubricant as they were completely degreased and when I've looked at the couple of new fuel filter housings that I have in my parts stash they appear to have some kind of clear grease on the plastic threads that I would love to know what it actually is as I feel it could prevent any potential shearing problems in the future ?

 

[vkx245l]

Happy new year everyone.

Right I need some help. I've just done a regular fuel filter change and as usual I print this thread off and follow Mike's (skipton01) advise.
This time I haven't any fuel coming through to the new filter from the tank.
I know this because;
I've started the engine from a diesel supply attached to the under bonnet lines ruling out the tandem pump.
I removed new filter which is wet with diesel(presumably from the return line)
As I removed it there was the usual cup full of diesel from the drain plug)
Very gingerly I released the fuel line clamps and nothing came out.
I have assumed the return line is now empty but why nothing from the tank.
I thought I might have a collapsed hose from the clamping but there isn't even a drip when manipulating it.
I have half a tank.
Any suggestions gratefully received.

Thanks Jonathan

 

[dj_efk]

Air lock? Someone else will chime in but did you fill the filter housing with fuel following the change via the pipes?

 

[vkx245l]

Air lock? This is where I'm scratching my head. The line from the tank to the filter housing is very short. I wonder whether the quick connectors have some sort of non return valve and I've disturbed one??

I don't think it's possible to prime the filter housing (1.4tdi AMF paper filter).

Thanks
Jonathan

 

[Catnip64]

Others have had success using a vacuum pump at the engine to pull the fuel through from the tank and remove the air lock.

 

[depronman]

This is a very typical issue when changing the fuel filter on the tdi because Audi did not fit a fuel pump in the tank and only have the tandem pump to suck the fuel through
Personally I have a large syringe that I use as a poor mans vacuum pump to suck the fuel through to the stainless steel pipes which cross the from of the engine
Once I get it to the pipes I clamp the rubber pipe and connect to the stainless steel pipe then have a second person crank the engine and only release the clamp once the engine is cranking. The tandem pump then only as a small distance to suck fuel and it fires up in 30 seconds or so
I have had an issue with the latter plastic housing where the housing cover was damaged and as a result the filter was not pushed up into the housing resulting in the valve not opening and no fuel flowing through the filter. This was a b****r to find as the filter was totally wet but nothing was flowing from the housing to the tandem pump but you have the earlier canister filter so this is not applicable to your issue

Paul


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[vkx245l]

I have had an issue with the latter plastic housing where the housing cover was damaged and as a result the filter was not pushed up into the housing resulting in the valve not opening and no fuel flowing through the filter. This was a b****r to find as the filter was totally wet but nothing was flowing from the housing to the tandem pump but you have the earlier canister filter so this is not applicable to your issue

Paul


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I have had an issue with the latter plastic housing where the housing cover was damaged and as a result the filter was not pushed up into the housing resulting in the valve not opening and no fuel flowing through the filter. This was a b****r to find as the filter was totally wet but nothing was flowing from the housing to the tandem pump but you have the earlier canister filter so this is not applicable to your issue

Paul


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I've not had any issues before and this will be the 10th change on this one! The last part of your reply is intriguing...
I have the later type housing with the paper element and can see the I side of the housing where the fuel tank line is attached the other side - is this the valve you speak of?
If so do you know how it operates? I'm scratching my head because if this valve closes once the filter is removed why do we clamp the hoses to drain the housing?

I've got the filter element removed, no lines clamped and half a tank of diesel, tank filler cap removed and no diesel flowing out???

Thanks Jonathan

 

[vkx245l]

I've just had a look at the parts diagram and thinkmy problem might be the fact that the pipe from the tank to the filter goes "up and over" to get to the filter housing and is now empty or blocked.
I'll check tomorrow and report back

 

[depronman]

The valve is inside the plastic filter housing so you don’t need to clamp the pipes on this style of filter
As soon as the filter drops down ( it is clamped up by the screw on bottom of the housing ) then the valve is closed so you only loose the fuel in the filter housing
There are a three webs on the screw on filter housing bottom and these had been damaged on a previous filter change
As the bottom was screwed on the webs folded down and hence the filter was not pushed up and therefore the valve was not opened
This took hours to find and work out what was happening

Paul


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[vkx245l]

The valve is inside the plastic filter housing so you don’t need to clamp the pipes on this style of filter
As soon as the filter drops down ( it is clamped up by the screw on bottom of the housing ) then the valve is closed so you only loose the fuel in the filter housing
There are a three webs on the screw on filter housing bottom and these had been damaged on a previous filter change
As the bottom was screwed on the webs folded down and hence the filter was not pushed up and therefore the valve was not opened
This took hours to find and work out what was happening

Paul


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This sounds like my issue.
Do you know whether it's possible to activate the valve with the element removed? This would enable me to rule out (or in!) the pipe to the tank.

Jonathan

 

[depronman]

If you push the filter up into the housing the valve will be opened

Paul


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[Guest 4123]

The valve is inside the plastic filter housing so you don’t need to clamp the pipes on this style of filter

There should be no need to clamp the tubes on the original fuel filter which are fitted with quick-connect connectors. Power washing beforehand will make everything more visible. VW did things more sensibly on the Lupo 3L with the fuel filter under the bonnet at the highest point. Drain back to the tank was avoided by the NRV. The job took about 10 mins! Not the case with the A2 filter!

RAB

 

[vkx245l]

All sorted. The hose at the connection with the stainless tubes under the bonnet had a small split in it which I clearly disturbed when checking the prime. This decided it would be a good time to draw air rather than diesel. So I cut the damaged piece off (Pic)
I did check the inside of the filter housing. The filter locates at the top but not to a valve that I could see. There is some sort of valve to the side of the housing but the filter element does not engage with it in any position.(pic)
Thanks for all the comments.
Jonathan