GAS STATIONS IN GERMANY
Filling stations (Tankstellen) are not nearly as prolific as in the US. Still, you should have little problem finding a place to 'tank-up' (volltanken) when you need to. Most small towns have at least one station, and there are 24-hour stations located at intervals along the Autobahn and major highways.
The major brands are Aral, Avia, BP, Elf, Esso, Fina, Jet, Total, and Shell. Most stations are now self-service (Selbstbedienung, or SB-Tanken.) Like the US, unleaded fuel (bleifrei) is now the norm.
At autobahn and other gas stations, you pump gas (or diesel) and then go inside to pay the cashier. (Lock your car and leave it at the pump, since no one can pump gas there until you've paid.) The cashier will ask for your pump number (You do know your German numbers up to 10, right?), so note that before you go inside. You can pay cash or use a credit card. Some stations require pre-payment during late hours, but usually you pay after you pump. Non-autobahn stations in Germany may or may not accept card payment. Look for the usual credit card logos at the door or by the register. (The EC card is not a credit card; it is a bank debit card for European residents only.)
Credit card readers at the pump (pay-at-the-pump) seem to be a thing of the past in Germany.
Pumps in Germany work basically the same as in the US. Europe uses a different formula to calculate octane ratings, so the scores will appear to be higher than those for corresponding grades in the US. Also, remember that fuel is dispensed by the liter.
Americans will likely experience 'sticker-shock' when it comes to gas prices in Germany. Expect to pay three to four times more for gas in Germany than in the US.
Diesel cars, also as rentals, are more common in Europe than in North America. When filling your car's tank with diesel fuel, make sure you do not mistakenly pull up to a truck diesel pump. The size of the nozzles for the auto pumps versus the truck pumps is different. A truck fuel nozzle is bigger and has a higher flow rate. It won't fit in the narrower automobile diesel fuel pipe.