Audi A6 2.5 TDi - Fuel Filter Replacement

Lord_Lardington

I’m planning to switch to biodiesel quite soon and am aware that it’s advisable to change your fuel filter shortly afterwards (apparently the biodiesel is a good cleaner and after the first thankful the filter can be a bit full).

Anyhow, I’ve bought the replacement filter and it looks super simple to change (a couple of jubilee clipped hoses).

However, before I do this I’ve got 2 questions:-
1) Does the new filter need priming with fuel before reattachment?
2) There is what appears to be a bleed screw on the filters, how is this used? Obviously to bleed air out but how do I do this? With the engine running? Can I expect to get diesel everywhere if I’m not quick?

Out of interest (and perhaps more fundamentally), if you have switched to bio, did you actually change your filter afterwards or didn’t you bother?

Thanks

chris147_2

I wouldn't have thought it would make much difference whether or not the filter is bled before starting the car.

If there is air in the system the car will just disperse it through the exhaust.

Plus, depending on how new the car is, most cars have the first filter in the fuel tank itself and then another one furhter down the line.

goldspanners

always fill the filter with diesel before fitting,in an ideal world the air would disperse through the exhaust but there is a tricky fuel pump in the way first,which doesnt like air.
usually filling the filter will be enough and wont require any extra bleeding,make sure the filter is tight,but not too tight when you fit it,a good hard final twist with your hand should be suffice if its a screw on type,if not make sure all clips are tight before starting the engine.
if you dont do this and expect the air to disperse through the exhaust it may be a time consuming exercise to get rid of the air once its in the system.
if you decide to open the bleed screw it will probably spray diesel everywhere so have a rag handy.

Pew_Pew_Pew_Lasers!

Ensure your battery is fully charged before you change the filter. It can take a lot of cranking to get rid of any air. Fill the new filter with diesel, preferably fresh diesel. The bleed screw should be operated with the engine cranking, you can't push air out if the pump isn't turning

Crank for 10 seconds max, and leave it for 20 seconds to cool down slightly. Repeat until she fires.

Once the engine is running take the car for a 10 minute drive to restore a bit of charge to the battery, otherwise you may find it won't start in the morning as the battery is flat.

anewman

Probably better to use proper petrol pipe clips than standard jubilee hose clips...

Lord_Lardington

Thanks all.

I've got the real-deal clips so should be ok. I'll make sure the brother-in-law is on standby with the jump-leads just in case...

Cheers