"valve" or "button" in diesel fuel filler tube?

Was putting fuel in and admiring another (newer) VW diesel, and buddy tells me that if he pushes a littlle button on the inside of the filler tube he can get another two gallons in.

Mine has that button too; I looked.

What is it supposed to be for - and is it safe to put the extra fuel in?

Reply to
jtaylor
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Found it (google) - is vent for the expansion area.

Suppose it's safe to fill as long as I'm hitting the road right away.

Reply to
jtaylor

Reply to
none2u

Not a good thing to do because it puts liquid fuel only where vapors should be.

Reply to
Lost In Space/Woodchuck

Reply to
none2u

Don't worry even if it is hot out. Diesel doesn't expand like gas does and these are also in gas VWs. Many of us with diesel VWs just remove the button so we don't have to hold it in filling. Called "venting."

Reply to
JEB

Reply to
none2u

If the button is removed you are also removing the part that closes the vent. Therefore, the vent is open all the time. Much easier than pushing in the button while fueling.

JEB

Reply to
JEB

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