What happens if I put a small amount of AdBlue in my diesel tank? (2023)

What happens if you put a small amount of DEF in diesel tank?

Typically, if DEF is introduced to the fuel tank, the truck will run poorly or even fail to start. Repairs to the fuel system can be costly. Components that have been contaminated with DEF will show crystallization after drying for a few hours as seen in Photo 1.

It is also prone to crystallization, which can clog fuel filters and injectors. This can cost you thousands of dollars worth of damage, and additionally, you won't be able to use your vehicle unless it is completely drained out and repaired.

If you do start the engine it's unlikely to run for very long. AdBlue is less dense than diesel, so will float on the surface, be picked up by the fuel pump and fed through the injectors.

Finding out whether you have an adequate amount of AdBlue® in your tank is usually straightforward enough – an amber dashboard warning light will typically alert you when your tank needs a refill.

If DEF enters the fuel system and spread throughout the engine it will ruin the diesel engine eventually. The fuel system lines are not compatible with DEF and slowly corrode and over time.

If your DEF drops below 2.5%, the light will be a solid amber. If you decide to ignore it, at the point where you run out of DEF, the light will glow solid red. It gets worse. If you ignore the solid red, your vehicle speed will be reduced to a snail's pace – 5 miles per hour – until you top up the DEF tank.

As AdBlue is not compatible with any engine materials it can very quickly corrode all components and pipework within the engine. If this happens the entire fuel system will need to be replaced. You must contact a professional to drain the tank immediately and dispose of all contaminated fluid.

Customers call with a wide array of issues, but a common-engine related call involves AdBlue. Poor handling, accidentally putting it into the diesel tank, and contamination are common occurrences, and these hiccups can cause severe damage to your equipment, incurring high costs of repair in the process.

The AdBlue tank is separate from the fuel tank, so it takes up extra space. If the AdBlue fluid is exhausted, the gas emission of the vehicle will increase and the engine locks and the vehicle does not allow it to run. You need to call the hammer. It can lead to both time and cost losses.

The exact answer depends on your individual driving style, vehicle load and engine. That said, you should be able to cover approximately 2,485 miles before your tank hits empty, if your car's equipped with our 2.0 CDTi engine, or as much as 4,038 miles in the case of our 1.6 CDTi.

Can I tip AdBlue down the drain?

You should also never pour Adblue onto the ground or into waterways as this can contaminate soil and water supplies. Taking your expired Adblue to a dedicated waste treatment facility gives you peace of mind that it will be disposed of safely and responsibly.

Depending on the type of vehicle, we can completely switch off the AdBlue for most cars or reduce it if desired. Even if the AdBlue pump is broken or, for example, the heating element in the tank malfunctions, we can often offer you a good and cheaper solution than if you have to replace the parts.

Most vehicles which require adblue will give you a warning when there's about 2-3 litres left. Depending on the vehicle and how you drive it, this will give you about 1,200 to 1,500 mile range.

It is estimated that a passenger car will consume approximately 1.5 litres of AdBlue for every 620 miles. The size of AdBlue tanks vary, too, so when you need to top up depends on your driving style, the number of miles you cover, and the size of the tank.

However, a tank of AdBlue^® can usually last between 2330 miles and 6835 miles following an AdBlue^® consumption between 1% and 6% of the diesel fuel consumption*.

DEF in a Diesel Tank Is Not Good

To make matters worse, you'll likely need to pay the bill as insurance policies don't cover the repair costs. So keep DEF out of your diesel tank, and you'll avoid making a stressful and costly mistake.

This includes mandating that all new trucks operating around busy railways and ports be zero-emission vehicles by 2024; phasing out all diesel trucks from those areas by 2035; and eventually taking every diesel truck and bus fleet off California roads by 2045, where feasible.

Some diesel owners are opting to “delete” these pollution-control components instead. A diesel delete involves taking out the DEF system, removing the catalytic converter and DPF, and installing a new exhaust. The vehicle's ECU (engine control unit) will also have to be reprogrammed using a tuner.

Diesel Exhaust Fluid (DEF) also known as AdBlue®, is a non-toxic, colourless, odourless and non-flammable fluid. Stored in a dedicated tank in your car, it is injected into the exhaust system to clean exhaust gases.

Exhaust is injected with DEF before entering the SCR catalyst, where it is then transformed into clean air that exits the tailpipe. If you let the DEF tank run dry, you could experience days, weeks or even months of downtime — along with thousands of dollars in potential repairs.

Should you keep your DEF tank full?

If the DEF tank contains less than 5% of its capacity, the equipment engine power will de-rate. Enough power will be available, however, to travel a short distance, so that you can add more fluid to the tank. The DEF tank needs to be filled once for every 3 to 4 times that you refuel with diesel fuel.

AdBlue™ is commonly mistaken as a fuel additive, when in fact it should not be mixed with diesel at all. Whereas diesel is for the running of the engine, AdBlue™ is designed for the SCR system in the vehicle exhaust and therefore is dispensed into a completely different tank to the diesel.

What causes AdBlue to crystallise? When AdBlue freezes (typically occurring at temperatures below -10°c), the solution can turn into a solid mass, causing it to clog up the system and prevent vehicles from starting. In extreme cases, this can damage your diesel engine beyond repair.

AdBlue favours regeneration cycles, so it participates directly in the maintenance of the diesel particulate filter. However, so that the diesel car's emission control system to work properly, it is necessary to make long trips (a minimum of 30 minutes) by regularly pushing the gears.

What happens if your car runs out of AdBlue? If you run out of AdBlue while you're driving, then the engine's power and performance will be reduced to 'limp home' mode to limit its emissions and once the engine has stopped, it won't re-start until the AdBlue tank is refilled.

AdBlue damages surfaces such as painted vehicle parts, plastic, items of clothing and carpets and should be removed as quickly as possible using a damp cloth and plenty of cold water. Any spillage can make a floor slippery and cause staining.

​ AdBlue® works alongside vehicle engine selective catalytic reduction (SCR) systems to reduce nitrogen oxide (NOx) exhaust emissions.

Key points: The fluid, which acts as anti-pollutant in diesel engines, is vital to the freight and logistics sectors. A global shortage saw a deal struck with Incitec Pivot to produce the urea-based fluid in Queensland. Freight and farming bodies say diversification is needed to secure the fluid's long-term supply.

If diesel fuel gets mixed with DEF, it may cause damage to the engine and the fuel system. These are not covered by the vehicle's warranty, so you better act as soon as you discover the mistake. The best results are expected if you stop right before putting the key in the ignition.

Early symptoms include hard starting, rough idle and smoking exhaust, and a DEF-contaminated engine may not start at all. The contamination can cause lines to rust, injectors to stick open and fail, and pump failure is also very likely. The recommend repair is to replace the entire fuel system, from tank to injectors.

Can you put too much DEF in a diesel?

Diesel Exhaust Fluid quality can be affected by: Crystallization: Crystallization can occur in a couple of ways – over-dosing and hard water top ups. Over-dosing occurs when too much DEF is added to the system – the DEF may not fully hydrolyze which can lead to crystalized deposits in the exhaust or injector nozzle.

AdBlue™ is commonly mistaken as a fuel additive, when in fact it should not be mixed with diesel at all. Whereas diesel is for the running of the engine, AdBlue™ is designed for the SCR system in the vehicle exhaust and therefore is dispensed into a completely different tank to the diesel.

Why does a diesel car need AdBlue? AdBlue helps to reduce emissions of nitrogen oxides, or NOx, from your car's exhaust. Euro 6 emissions standards, which apply to all cars built since September 2015, place very strict limits on the amount of NOx that can be emitted legally.

The software bypass is a temporary fix until new sensors are made available. The bypass is only available to vehicle owners after the DEF sensor fault light indicator signals the first of three warnings before the engine is shutdown. Software patches will not be made available if no sensor lamp is illuminated.

If the DEF tank contains less than 5% of its capacity, the equipment engine power will de-rate. Enough power will be available, however, to travel a short distance, so that you can add more fluid to the tank. The DEF tank needs to be filled once for every 3 to 4 times that you refuel with diesel fuel.

Does DEF shorten engine life? If DEF enters the fuel system and spread throughout the engine it will ruin the diesel engine eventually. The fuel system lines are not compatible with DEF and slowly corrode and over time.

Exhaust is injected with DEF before entering the SCR catalyst, where it is then transformed into clean air that exits the tailpipe. If you let the DEF tank run dry, you could experience days, weeks or even months of downtime — along with thousands of dollars in potential repairs.

Most DEF tanks require one gallon of DEF for every 50 gallons of diesel fuel, and one gallon will generally last between 300 to 500 miles.

DEF is consumed at a rate of about 2-3% relative to the amount of fuel you are using. This means between 1.2 and 2.0 gallons of DEF will be required for a vehicle with a 65-gallon gas tank. If you have a five-gallon DEF tank, DEF should be replaced every third or fourth time you fill up.

Does DEF float on diesel?

* Diesel is less dense than DEF and will float on top of the DEF in the tank, but even small amounts of diesel can damage the exhaust system.

According to the owner's manual, a full DEF tank should last 6300 miles, but, as everyone knows by now, your mileage will vary.