I gave my car a service yesterday and when I took out the fuel filter it was completely black. Is that the way it's made or is it full of dirt?

 

When I bought the car, I contacted the servicing dealer and they confirmed that all the filters had been changed at the 90k service. I'm now on just over 120k so they were due for a change. I've a suspicion the filter I replaced may have been on since new!

I suspect you're right.

 

When I changed my fuel filter after 40k it was still as clean looking inside as the new one I replaced it with.

 

Air filter was filthy after only 10k though.

I just replaced all of mine just now; They were done a year ago by dealership.

 

Apart from the air and pollen filter, they were absolutely filthy! In fact, worryingly so. Given how easy they are to change and I think for something like £5, I may consider changing them every 6-months. Overkill I know but seems like a small price to pay.

The black scum you get on diesel fuel filters is actually a by product of bacteria that breaks down the fuel.

 

I have seen this in nearly all diesel filters I have changed, and it seems to be normal. It's a good reminder to change the filters regularly.