Rusty fuel filler

[JHZR2]

Never seen this before on any of my cars.





There would have to be a LOT of moisture or water in there to cause such rust. I just don’t see it. It is a high mileage car, 291k miles. But it is clean and straight throughout.

I guess a bad fuel cap over time could let this happen, but then there should be water in the fuel. The car has lived outdoors for many years. Car runs perfect. Prefilter is picking up bits…



Any thoughts on a better filter that will fit a w140? Like a Parker raccor or something?

[SonnyMorrow]

Makes you wonder what the inside of the tank looks like. I bet it's rusted on account of that filter. Never seen one like that either. I would maybe look into getting a new tank, and replacing lines if you really care. At 300k miles you might want to just keep driving as is.

[Clemson88]

Tank has to come off and be cleaned. There's many threads addressing this issue here. Running a car low on fuel allows changes in temperature to pull in fresh air when temps fall and expel air when temps rise.

That rise and fall of temps creates a system of air changes in the tank which draws moisture into the system. That condenses on the cap and neck because they cool faster than the rest of the tank assembly. When enough moisture condenses it forms drops of water on the neck and cap then gravity draws it to the bottom of the tank.

I faced that in my w126 project car and was warned that the rust would find its way to injectors. I'm not positive that is a fact but I took no chances.

[vwnate1]

I've seen more than a few like this, usually caused by leaving the tank nearly empty .

I too would drop and de rust the tank, it's very easy and requires no dangerous chemicals .

The filler necks were galvanized or plated when new so mayhap get another better one used ? .

Pulling the tank is a b*tch if you have a back back .

[JHZR2]

Thanks all. Anyone know how to pull the tank from a W140?