Yes, you can put diesel in a petrol (gasoline) car, but you absolutely shouldn't, as it will cause problems because diesel doesn't ignite with spark plugs like petrol does, leading to rough running, smoke, and potential fuel system clogs, but it's generally less catastrophic than petrol in a diesel engine; if you do, do not start the engine, get it towed to a professional to drain and flush the entire fuel system to avoid costly damage.
How Far Can You Drive with Diesel in a Petrol Car? As the diesel will cost the spark plugs and fuel system, your engine can misfire or may not start at all if you put diesel in a petrol car. If you are able to drive at all, you will likely only be able to travel a few miles on diesel before the engine shuts down.
Providing that you have put less than 10% of a full tank of petrol in diesel, equating to 5 litres or less, you should be able to get away with filling the tank full with the diesel and your vehicle should be able to burn off any contaminated fuel without the need to call for assistance.
Putting diesel into a petrol engine causes poor combustion due to diesel's higher ignition temperature. Symptoms include rough idling, stalling, and difficulty starting. Immediately avoid running the engine; drain and flush the entire fuel system, including fuel lines, injectors, and fuel filter.
Effects of Diesel Contamination on Gasoline Vehicles
Your external fuel filter becomes clogged with diesel's oily substance. Fuel injectors get blocked and become inoperable. Engine performance deteriorates rapidly. The vehicle eventually stops running completely.
After starting your engine, the diesel will coat spark plugs and the fuel system, which often leads to misfiring. Your engine may give off smoke, cut out, or fail to start at all. You should drain the fuel system as soon as possible.
Putting diesel into a gasoline car is a common misfueling mistake. The wrong fuel can cause misfiring, breakdowns, and expensive repairs. In many cases damage begins as soon as the engine starts and runs. The actual harm depends on how much diesel entered the tank and how long the engine ran with mixed fuel.
The vehicle may misfire, stall, or not start at all. Clogged fuel system. Diesel, with its thicker consistency, can potentially gum up fuel lines, filters, and pumps if the engine runs even for a short period.
– The easiest way to ungel diesel fuel is to get the vehicle into a normal temperature zone. You can push it into a heated garage or simply wait for the temperature where your vehicle is parked to rise. The fuel will return to normal naturally.
Fuel system cleaning costs typically range from $100 to a few thousand dollars per vehicle. The cost depends on a few factors. The primary factor is the amount of deposits in the fuel system. If your vehicles haven't had a fuel system cleaning for a while, expect the cost to be on the higher end.
What is the Half-Tank Rule? Always keep the tank in your vehicle at least half-full. It is that simple.
What Happens?
As a safe amount the industry generally accepts 5% or less of diesel in petrol is OK. When you work it out for your tank capacity you will soon realise it's not a lot of the wrong fuel before it's too much.
If you're in for long car trips, choose diesel over petrol engines since they provide more power at lower engine revs. Featuring better fuel economy. Diesel cars give their owners better mpg than their petrol counterparts due to their fuel containing more energy per litre. Lower CO₂ emissions.
If you mistakenly put a small amount of diesel in a gas vehicle, it's usually fine. With a larger volume of diesel, though, you may need to clean or replace your fuel injectors. This is because diesel is thicker than gas and can clog your fuel system.
While some car insurance policies include misfuelling cover as standard, this is not common. You may be able to add it as an optional extra, but a lot of insurers will not offer misfuelling cover at all. A misfuelling policy should cover the cost of draining and cleaning the fuel tank.
The fastest way to ungel diesel fuel involves using a dedicated emergency de-gel additive, applying it to the fuel tank and filling the fuel filter with it, then allowing time for the engine's heat or external gentle heating (like a heat lamp) to circulate the product and melt the wax crystals, effectively restoring fuel flow. Simply adding a general anti-gel to the tank is slower; the key is to get a rescue formula into the filter and lines quickly.
The worst things for a diesel engine involve neglecting maintenance (especially oil/filters), using poor fuel quality, allowing low fuel levels, overloading/lugging the engine, and not letting it warm up/cool down properly, all leading to contamination, excessive wear, turbo damage, and injector/pump failure due to high pressures and sensitive components. Contaminated fuel (water, dirt, high sulfur) is especially damaging, corroding parts and clogging filters in these high-pressure systems.
As the temperature climbs above the fuel's gel point, the diesel will naturally return to its liquid form. Of course, this may not be an option if you find yourself in the middle of a cold snap and you have somewhere your vehicle needs to be.
Final Thoughts. Petroleum hydrocarbon exposure in cats is a veterinary emergency. With rapid decontamination, supportive care, oxygen therapy, and protective antibiotics, many cats recover completely—though aspiration pneumonia remains a serious risk.
Immediate actions
Putting diesel in a gas engine, even in small amounts, can lead to immediate problems. If you mistakenly put diesel in your gas engine, the damage can happen quickly, often within the first few minutes of driving.
In fact, if you have only put a very small amount of Diesel in your Petrol tank (under 5%) you might even get away with running the car. Our professional advice, however, is always to have the mixed fuel removed from your car as soon as possible for complete peace of mind.
When petrol is added to diesel it reduces its lubrication properties, which can damage the fuel pump through metal-to-metal contact and create metal particles causing significant damage to the rest of the fuel system.
Misfueling, or inadvertently putting the wrong fuel into your vehicle, poses serious consequences to the health and performance of your vehicle. This is especially true when petrol is mistakenly added to a diesel car. Petrol and diesel fuels combust differently, so using the wrong fuel type can disrupt engine function.