Passenger cars hold about 40-70 litres, pickups 80-135 litres and semi trucks 300-600 litres, but abandoned tanks are rarely full, so confirm the fuel type at the filler door and judge the level before extracting anything. Work outdoors on level ground with the collection container standing on the ground, pump the fuel out rather than sucking on a hose, and stop short of the tank bottom, where water and sediment collect.
Part of Fuel Siphoning & Storage
Vehicle tanks are the most abundant fuel in any town, but their contents vary with fuel type, battery-dependent gauges and how long the car has stood. Size-up and preparation decide how safe the extraction is; the pumping itself is covered under pump siphons.
The Fuel Type Decides Everything Else, So Read The Filler Door First
Vehicles carry a label on the fuel door or just inside it saying what to put in. A gasoline label and a diesel label mean different extraction hazards and different uses for the result. Gasoline puts you in the vapour-explosion case treated on Fire & Vapor Safety. Diesel is harder to ignite but is a poor choice for a gasoline engine and the reverse; never put one in a vehicle or container meant for the other.
Typical capacities from the parent article: passenger cars 40-70 litres, SUVs and minivans 60-100 litres, pickup trucks 80-135 litres, semi trucks 300-600 litres, delivery vans 80-120 litres.
What You Need
- A pump or transfer hose set — see Pump Siphon & Transfer Pumps. A hand pump is the safest tool; do not start a siphon with your mouth.
- Metal or approved plastic container, clean and dry, sized to the expected volume (see Approved vs. Improvised Containers).
- A clean dry stick or wooden rod for judging the level.
- Eye protection and gloves, since fuel splashes and degreases skin.
- Dirt or sand and a bucket within reach for a spill.
Method: Prepare, Check, Then Extract
Step 1: Position. Work outdoors, on level ground, away from other vehicles. Not under a roof, not in a garage and not beside a running engine. A parking garage concentrates vapour; take the vehicle out of it or leave it.
Step 2: Open the filler. The fuel door is usually on a rear quarter panel. If the door release is electric and dead, pry the door with a flat screwdriver. Turn the cap slowly and listen for a hiss; a hiss is pressure or vapour escaping, and you should wait until it stops.
Step 3: Check the level without a flame. Lower the clean dry stick through the filler until it touches the bottom, withdraw it and read the wet line. Keep your face turned away. Do not use a lighter or match to look into the tank.
Step 4: Container on the ground, in contact. Set the container on bare ground, not on a car seat, carpet or plastic bed liner. Keep the pump nozzle or hose end touching the container rim during the transfer, so any static charge equalises through metal instead of jumping as a spark.
Step 5: Extract and stop early. Draw the fuel with the pump, keeping the intake a few centimetres above the tank floor. The last portion contains sediment and any water that has settled. Leave it in the tank.
Step 6: Close and record. Seal the container, label the fuel type, close the filler and note the vehicle so nobody re-opens an empty tank.
Worked Example
Twenty cars at 40-60 litres each would hold 20 × 40 = 800 to 20 × 60 = 1,200 litres if every tank were full. If the tanks average one quarter full, that is 800 ÷ 4 = 200 to 1,200 ÷ 4 = 300 litres. The one-quarter figure is an assumption for illustration; measure the real level at each filler.
Common Mistakes
- Trusting the gauge. It works only while the battery has charge and may be stuck. Check by sight.
- Draining to the bottom. The dregs hold water and sediment that block filters and corrode injectors, so you carry the problem home.
- Cutting into the fuel line as a first resort. It is slower to set up and the line may still hold fuel under pressure. Try a pump or thinner tubing first; see Bypassing Anti-Siphon Devices.
Safety
Fuel vapour and static ignite gasoline tanks
Gasoline vapour is heavier than air, collects in footwells and low ground and ignites from a spark, a hot exhaust or static discharge. Open and work outdoors only, with nothing burning, running or switching nearby. Never put a flame in or near a filler opening to look inside or test for vapour. Never fill or transfer into a plastic container sitting on a seat, carpet or bed liner, because static can build on the container; keep it on the ground with the nozzle touching it. Never start a siphon by mouth: swallowing or breathing gasoline can cause chemical pneumonitis, which can be fatal.
What’s Next
- Learn next: Bypassing Anti-Siphon Devices — when the hose will not go in
- Combine with: Approved vs. Improvised Containers — what to carry it in