Common questions.
Short answers.

A robust, fabric-reinforced tab behind the fuel flap that shows the right fuel when you refuel. It has to be lifted to refuel, so it doesn't get overlooked.

Yes, it fits all common cars and vans. It is stuck on above the fuel cap, behind the fuel flap.

No, the Tankfreund is made for cars and vans.

B7 diesel (red), E5 and E10 petrol (yellow) and HVO. A single order can be split freely across the different fuels.

Yes, with the fuel names used in the main European travel destinations.

In 2 minutes: clean the area above the fuel cap, peel off the film, press down firmly. Full adhesion is reached after 24 hours.

From 5 °C. Full adhesion is reached after 24 hours.

Made of robust, fabric-reinforced PVC, less than 2 mm thick and 7.6 × 12.55 cm in size, with a high-performance 3M adhesive pad.

Yes, we will send you plain samples by post.

Yes, with your logo, a promotional message or an emergency number. You will receive a design for approval; the design work is included.

Prices on request, with quantity-based price tiers.

Depending on production workload, 4–8 weeks; for Tankfreund tags with a logo, counted from approval of the design.

No, we now supply commercial customers only and ask for your understanding. Simply ask your dealership, insurer or automobile club about the Tankfreund.

In Germany, more than 200,000 times a year according to the magazine auto motor und sport (2019), or roughly once every two and a half minutes.

Petrol in a diesel car. Petrol breaks down the lubricating film that the high-pressure pump and injectors need; modern direct-injection diesels are particularly sensitive. Diesel in a petrol car puts strain on the injection system and exhaust aftertreatment; with only a little diesel, according to ADAC (Germany's largest automobile club), topping up with the right fuel is sometimes enough.

In Germany, pumping out costs roughly €150 to €500, depending on whether the car has to be towed and the fuel disposed of. If the engine has already been running, the injection system often has to be replaced; according to ADAC, that costs several thousand euros.

In Germany, yes. Insurers classify misfuelling as operating damage. Motor liability insurance and partial or fully comprehensive cover (Teilkasko, Vollkasko) then generally don't pay, not even for rental cars or company cars (R+V, a German insurer, as of May 2025). In many other European countries, too, motor insurance often doesn't cover misfuelling damage, or only part of it (for example in the UK, France and the Netherlands).

Some breakdown cover packages (in Germany, a “Schutzbrief”) pay for pumping out and towing up to a maximum amount; VGH, a German insurer, for example pays up to €500, according to a VGH insurance agent in our video. Breakdown cover generally doesn't pay for engine damage. What exactly applies is set out in your policy terms.

That depends on how serious the mistake is, and the rules differ from country to country. In Germany, for example, employee liability is graded: for a minor slip the employer bears the damage, for medium negligence it is shared, and for gross negligence the driver generally bears the full amount (Heuking, 2024). German courts have repeatedly treated misfuelling a company vehicle as grossly negligent, most recently the Federal Administrative Court in 2017 in the case of a police officer who had put petrol in a diesel vehicle. In many European countries, motor insurance often doesn't cover misfuelling damage, or only part of it, for example in the UK, France, the Netherlands and Germany.

Often yes. At 25 mm, the diesel nozzle is thicker than the petrol nozzle at 21 mm, but according to ADAC it can often be inserted into the upper part of the filler neck.

B7 is the EU-wide label for diesel containing up to 7% biodiesel. It appears in a square on the pump, on the nozzle and on the fuel cap; petrol grades such as E5 and E10 appear in a circle. If the symbols match, it is the right fuel (ADAC). The Tankfreund is available as B7 diesel in red.

The ethanol content: E5 petrol contains at most 5% ethanol, E10 petrol up to 10%. In Germany, almost all petrol cars in circulation can run on E10; whether yours is one of them is stated in the owner's manual, on the fuel cap or in the list from DAT (Deutsche Automobil Treuhand) (ADAC). The Tankfreund is available for E5 and for E10, both in yellow.

Only with the manufacturer's approval for your model. HVO100 is paraffinic diesel to DIN EN 15940, permitted at German filling stations since the end of May 2024 and labelled “XTL” there. Approved cars can be recognised by the XTL mark on the fuel cap, in the owner's manual or in the DAT approval list (ADAC). For vehicles with approval, the Tankfreund is available as an HVO variant.

The Tankfreund works like an insurance policy: a single pump-out costs about as much as Tankfreund tags for 100 vehicles.

Cambio CarSharing found the Tankfreund “considerably more effective than the usual stickers”.

No problem: test samples, quote to procurement, delivery to head office or to individual sites.