I bought my Treg CPO with 35K miles on it, and shortly thereafter changed the fuel filter, presumably for the first time. It looked even blacker than yours.

My conclusion is that even though the manual calls for changes at 40K mile intervals, it should be changed every 20 K miles, and that's with a reliable source of clean fuel....sps

 

Viper4, I have never seen dirt like that in a diesel filter (from commercial fuel in North America), that looks just like the dead bacteria ("bugs") that come from contaminated diesel fuel, and live on the oil water interface in fuel tanks that are contaminated with water. They grow in mats, eat oil, die, drift away and plug up your filters with a black deposit. If it's "bugs", you need to drain and flush your tank and fuel system, then use a kill dose of a biocide, like BioBor. And change the filters until all the dead bacteria are out of the system.

 

WoW,
You guys sure know how to EGG someone into changing their filter. I'm the second owner at 30k miles and wonder now. Only way to know is to do it....

 

Great Day, that's just looks nasty. I agree, I'm motivated by sheer disgust to want to change my fuel filter also. Just might do so now that my car is currently at the shop.

Or is the filter a simple DIY for a T1?

 

I never did my 05 v8 as it was gas so i don't know. But the diesel is another story. Where is it located on a 2010 tdi is what i need to know?

 

Yeah I suppose I may look into some ways to test for fuel system contamination. Hopefully it was just overdue for a filter change! Haha. Replacing the filter is a really easy task. 20 minute job.

http://www.clubtouareg.com/forums/f43/t2-3-0-tdi-fuel-filter-change-success-120705.html

 

I did my fuel filter last week and it was dirty, but not as bad as the one in Viper4's photos. Now that I have done it, I plan on doing it every 20K miles as others have posted.

I also changed my engine air filter last year before the suggested mileage interval and it was extremely dirty. After I did it, I got 2 miles per gallon increase in the MFI. It is like the fuel filter, once you do it, it is easy to do and I plan doing it every 20K. The engine air filter is also a lot cheaper than the fuel filter.

 

I just read this description of diesel algae.

http://www.diesel-fuels.com/pdf/Guide_1.pdf

After reading it I kinda doubt this is the problem. The filter isn't particularly slimy, broken down or black. And the water that remained in the filter bowl had no brown tinge to it. It looked totally normal.

Here are closer pictures of the filter. As the filter dries out the lighter brown it looks. Makes me think this is just a neglected filter.

 

I just read this description of diesel algae.

I'm curious if you're using a fuel additive like Howe's or PowerService or not.

I know the former is meant to boost lubricity, prevent gelling, and prevent algae growth -- which is why I use it in each tank at fill-up. Diesel Treat in winter, Meaner Kleener in the summer.

 

...after the experience with my post above, I changed the filter again at a further 15K miles, and found it yellowed, but clean, so bacterial contamination was apparently not the issue. The TDI continues to perform as anticipated.

However, I still think that 40K is too long an interval...sps

 

Yeah Sierradeux, I like the every 15k idea.

 

Is it only the TDI that has the fuel filters or does the T3 have it as well?

 

Horton, I just started using diesel kleen in the Touareg. I haven't had the Touareg long though. I usually use Opti Lube in the truck. I just need to order more of that for both vehicles.