Fuel Filling SLK250d

[Mickyh7]

Hi, I've googled this a lot, but never got to the bottom of it.
When I fill up with Diesel, I have no problems until the last 4 gallons (20 ish litres).
It takes forever to get that last bit in, I can see it coming up the filler neck, cutting the nozzle off, then slowly going down the filler neck.
I've tried moving the nozzle in all positions, and it doesn't help.
Has anyone actually had this problem, AND solved it?
Lots of guessing on the Internet, but no real answer!
Anyone please?

 

[st13phil]

Sounds like perhaps the diesel is foaming in the filler neck and causing what amounts to an airlock? If that's the case, then slowing the rate of fill should reduce the foaming and prevent the pump blowback sensor stopping the flow.

Alternatively, get a petrol-engined SLK

 

[Mickyh7]

Sounds like perhaps the diesel is foaming in the filler neck and causing what amounts to an airlock? If that's the case, then slowing the rate of fill should reduce the foaming and prevent the pump blowback sensor stopping the flow.

Alternatively, get a petrol-engined SLK

No, like I described, I can see the Diesel slowly come up, and slowly go down the filler, with no foam present.
Good Guess though
Incidentally, both petrol and diesel tanks are the same, only the fuel pump is missing from the Diesel version, which has a swirl chamber fitted instead!

 

[st13phil]

Incidentally, both petrol and diesel tanks are the same

I know. And I can fill the SLK55's tank at full chat right up until the last litre or so which means the only difference is the type of fuel.

My view is still that the diesel is foaming - albeit out of sight down the bottom of the filler neck - and effectively creating a partial airlock.

 

[Mickyh7]

I know. And I can fill the SLK55's tank at full chat right up until the last litre or so which means the only difference is the type of fuel.

My view is still that the diesel is foaming - albeit out of sight down the bottom of the filler neck - and effectively creating a partial airlock.

I hear you.
But four gallons of foam?
That's 20 litres of foam, 33% of the tanks capacity.
It would be well below the start of the moulded filler neck on the tank.
Maybe 4 pints!
My thoughts were down the lines of the Evac valve or vent tube.
But then, I'm only guessing?

 

[st13phil]

I hear you.
But four gallons of foam?

Good point