Understanding Diesel in a Petrol Fuel Tank
Because diesel fuel pump nozzles are wider than standard unleaded filler necks, putting diesel into a petrol car is harder to do accidentally—but it occurs with fuel cans, jerry cans, or adapted fillers.
Symptoms of Diesel in a Petrol Engine
If you have driven away with diesel mixed into your petrol tank, you will quickly notice:
- Engine misfiring, heavy smoking, or sudden loss of power.
- Engine stalling and refusing to restart.
- Unburnt diesel smoke coming from the exhaust pipe.
Is Diesel in a Petrol Car Catastrophic?
Generally, diesel in a petrol engine causes less permanent damage than petrol in a diesel engine. Diesel is heavier and oily, which clogs spark plugs and fuel injectors. However, the system must still be thoroughly drained and flushed to prevent long-term catalyst and sensor contamination.