Anyone else got this? Looks a bit manky :(

Unless you have never spilled any fuel over these metal parts (they're coated with thin film of diesel in my car, and look pristine), it is likely that substandard fuel was in the fuel tank at some point in the past    Either bleached agro fuel, containing traces of sulphuric acid, or below standard biodiesel, containing way too much water. Is it a recent thing, or has it been going on for some time? New petrol station perhaps?

 

I'd worry more about the rest of injection system, as fuel filter would not have removed the acid nor the massive amount of water suspended in biodiesel, and the dodgy fuel would scar injection system parts much more under high pressure/temperature.

Edited 16 December, 201411 yr by dieselV6

I've never used any non-UK forecourt pump diesel - but don't know the history of the car before 40k miles (132k on clock now). Car seems to run as well as ever. Ho hum :(. I had never noticed it before, so I wonder if it coincides with the ventectomy somehow - but can't see how.

So it looks like the filler neck isn't quite as bad as it looks after rubbing it with a bit of paper towel - but it does look like a recent-ish problem.  I noticed quite a bit of condensation on the back side of the fuel cap when I opened it this evening - and I had dried it off yesterday.  I took the car for a wash today.  I wonder if the fuel cap is not sealing particularly well and letting a bit of pressure washing in...

I suspect somehow you ended up with dodgy water contaminated diesel in the tank!

I'd keep adding fresh diesel from a different fuel station and draining the fuel filter for any accumulated water. And monitor the condensation situation. In the meantime I would not drive the engine hard.

How annoying. I noticed the rust a while ago so I imagine most of it has run through by now. I will probably change the fuel filter at this next coming service again as a precaution.

I avoid low volume fuel pumps at all cost... they have the highest chance of ending up with an unacceptably high water content as fuel sits around for a long time before a fresh delivery...

Safest bet are high volume pumps on main roads or even supermarkets... at least a low detergent content fuel won't kill the fuel system, but water most certainly will.

But anyway, might have been something else... And your car seems fine, so not too bad...