Dirt & water in diesel - Martin
A friend has just purchased a 6 month old tdi (115 pd ) passat. It broke down and the VW garage found water & dirt in the filter. It needed a new fuel pump costing £500+.

He cannot point the finger at particular filling station or indeed the muck may have been in prior to his purchase.

VW say it is not a warranty claim which seems fair enough however two points

1.What is the point of a fuel filter if it lets muck & water ruin the engine ?

2.He had taken it to two separate VW dealers prior to the breakdown complaing of the engine spluttering when starting and they had both plugged it into the VW computer and reported no fault found.

Any comments ?


ps My own 1995 Golf tdi (90 bhp ) has a plastic drain valve on the fuel filter to run off water etc but the Passat PD is a sealed system.
Re: Dirt & water in diesel - Andrew Hamilton
I am shocked that any diesel fuel filter would not have a drain valve to remove water. Although I have never seen any water, when servicing the vehicle, I could imagine it happening. There is usually a prefilter before the fuel pump to remove any large bits - at least in the diesels I looked at.
Re: Dirt & water in diesel - Tristan Chaize
I agree with Alvin. Main dealer rip off.
Re: Dirt & water in diesel - Alvin Booth
I have never heard of a fuel filter allowing dirt through to to the pump.
I do know that a diesel pump can be damaged by particles hundreds of times less in size to an human hair but filters have no problems in removing them.
Water is a different matter of course and the filter will of course not prevent this.
However any water present will sink to the bottom of the filter and can be drained off normally through the drain off you mention although I have never found any present when I have carried this out.
I have never seen any vehicle without this provision for removing any possible water. The fuel does of course act as a lubricant to the pump and water would not provide this.
You say that it seems fair that VW would not allow a warranty claim on this but I would disagree. It seems a easy getout to the dealer to say he found dirt and oil in the filter ( which is where it should be if it had somehow got in) and they must have had remarkable eyesight to see it anyway.
basically they are saying that our filter has allowed dirt to get through to your pump and we are going to make you pay for a new one.
It all sounds dodgy to me and I would have asked them to present the pump to an independant pump specialist to present their findings.
Also as a last point martin dealers are not diesel pump specialists and it would appear they have simply bolted a new one on and it cured the fault!!!


Alvin Booth
Re: Dirt & water in diesel - Ian Chandler
Provided you buy diesel from reputable filling stations it's very rare to get any water at all in your filter. I have had diesel cars since about 1982 and have never found water when I have checked the filter at 10,000 miles, or changed it at 20,000.

It's also very unusual to find dirt. What is more common is a black, sticky rubber-like contamination in diesel which can totally block the filter. I've read complaints from train operators about this - it's caused railway breakdowns and fuel suppliers were blamed.

In VW cars there is often a small plastic filter actually in the fuel tank. To get it out you have to unscrew the fuel-gauge sender and remove it, then fish into the tank with a length of coathanger wire.

If you ever do get black sticky-stuff contamination it can totally block this tank filter. You then get the diesel pump creating a vacuum or sucking in air from any tiny hole in the fuel line, which of course stops the engine. It is a fault which can totally fox garage mechanics.

But straight dirt is unusual - it could be from agricultural diesel used illegally by the previous owner, or from fuel syphoned from a truck, or the last owner of the car could have run the tank almost dry in which case all the crud from the bottom of the tank might have found its way to the filter - but then a fairly new VW shouldn't have too much crud at the bottom of its tank ... very strange.
Re: Dirt & water in diesel - Martin
Thanks everyone for the imput,

The car was an ex rental one so someone could have put something into it I suppose. Had done about 8,000 miles . Still had the VW warranty though.

But my pal did ask 2 garages to check the car when it started to sputter slightly .


What is the point of a filter. I had always assumed that the vehicle would just stop to prevent damage.


Value my car