Fuel Cap Lost!!!

This is soooooo bad, I let my girlfriend borrow my 01' Jetta TDI to drive to and from work last week as hers was in the shop. And whatta ya know, she leaves the fuel cap at the station. I went back to the station and nothing! My question is will this hurt my mpg until I get to the dealer and get it replaced? Also, will this cost me much?

Its $13.35 at VWParts... VWParts - Jetta Fuel Filler Cap

Doubt if any impact on the mpg, but should cover it with a clean rag temporarily to prevent any contaminants...just make sure it doesn't fall inside.

Thanks for the tip, wanted to make sure this will work for the TDI(the cap itself), is there any difference in this and the gasser?

I drove a ccross country, all over the rockies and back to the east coast without a fuel cap for my Peugeot 405 gasser. I used a rag, although my fuel door was gone as well; so I wrapped the rag in a zip lock to make it more or less water tight. No troubles....with the fuel anyways.

You might want to try this for a while and hold off on the new gas cap. It definitley gives you that self-reliant, bad ass kind of feeling at the gas station.

In as much as anything to do with a Peugeot 405 wagon is bad ass, that is.

The gassers have a sealed system and sensor if the tank depressurizes and leaks vapour, but the diesel doesn't have that system and the tank doesn't get pressurized (right?).

better listen to mister bigglesworth, because "when mister bigglesworth gets angry, people die!"

Go to a local auto parts store. They're sure to have a fuel cap. Whatever they have that fits a gasser will work for yours, if they don't have a listing for a TDI. <$10 usually.

You can even get a locking cap from Kragen. In case you live near jerks with more sugar than they know what to do with.

Until you get a new gas cap, the plastic cap off of a 5 gallon watter bottle will work. I is just a snug fit, and pop it off for fill ups.

quoted:
The gassers have a sealed system and sensor if the tank depressurizes and leaks vapour, but the diesel doesn't have that system and the tank doesn't get pressurized (right?).
end quote

Not according to my dealer (who loves diesels!). According to him, not putting on the gas cap and not turning it until it clicks several times will lead to low pressure in the tank and a check-engine light on the dash. It's not hugely serious, but you can't just tap the odometer button and reset the CEL light.

Steve-o the dealer is wrong. There is no sensor for tank pressure on the TDI.

If that's the biggest mistake she has made at the service station, consider yourself fortunate!

It could have been worse, she could have put gasoline in!

Thanks for your responses, I can always count on this board for everything TDI!