Fuel Doctor Frequently Asked Questions

Fuel Doctor is a 100% Australian made fuel conditioner originally formulated to clean all types of fuel in inaccessible industrial underground storage tanks. As such, it is effective in all diesel, petrol, and two-stroke fuel systems.

Put simply… Fuel Doctor cleans and protects your entire fuel system while giving optimum combustion and minimum pollution every time you use it. And, as an added bonus, it will also stabilise and extend the life of fuel in storage tanks or jerry cans for up to 5 years.

For more details, please see: “How does Fuel Doctor work?“

Fuel Doctor Fuel Conditioner is a proprietary formula of oxygenated molecules, which work to break down fuel contaminants (such as water and fungal material) into sub-micronic particles, and emulsifiers which take those particles and disperse them into the fuel. These particles are then able to pass through your fuel system, without causing any harm to your fuel pump or injectors. It helps to protect your engine by lubricating any microscopic solid particles which are then able to pass through your fuel system and upper engine.

It will also dissolve carbon, gum, varnish, and other built-up contaminants in your fuel lines, fuel pumps, carburettors, injectors, and on valve faces, taking them through combustion safely.

Absolutely. Check out this short video from Fuel Doctors™ demonstrating how Fuel Doctor works.

Dirty fuel is any fuel with contaminants in it. This means that almost all fuel is “dirty”. Around 80% of underground fuel tanks have water in them. Water provides the oxygen source for fungal spores (Cladosporium resinae) to grow and consume their favourite food—the hydrocarbons in fuel. Water from condensation also promotes flash rusting of underground tanks, which flakes off into the fuel, unleashing abrasive particles.

When a road tanker delivers fuel to your local service station, it fills their underground tanks at 800-1000 litres per minute, stirring up the existing debris and agitating the contaminants in the tank, mixing them into the fuel. As a result, you can never be sure what contaminants are in the fuel you buy.

If you buy any amount of fuel any time up to two days after a road tanker has filled a service station’s underground tanks, you run a high risk of the fuel being contaminated.

The immediate danger period after a tanker refill varies depending on ambient temperature and the degree of contamination already in the tank, but it’s usually 2-4 hours in summer and 4-12 hours in winter.

Many consumers are lucky and never fill up in the post-fill danger period. But every time you buy fuel, you have the potential to introduce these unseen contaminants into your fuel system.

Fuel Doctor is the simple, inexpensive answer to this problem, and provides a high level of quality assurance for any amount of fuel you put in your car (or other vehicles and machinery).

Any underground storage tank from any commercial service station, industrial storage facility, or private tanks. The dirty fuel coming from your storage tank can be minimised by treating your fuel with Fuel Doctor before use.

The main contaminants of fuel are water, fungal material, and rust. There is residual water in all underground tanks from new, and various factors such as engineering, maintenance, and environmental issues can cause more water to enter under/above-ground fuel tanks. Fungal material comes from spores (mainly Cladosporium resinae) that can enter the tanks any time they are opened, filled, cleaned, etc., via the breather systems that are always open. As a side effect of water contamination, rust is formed when steel and iron components inside fuel storage tanks are also exposed to air—every time the tank isn’t completely full.

While your boat's fuel filter is designed to capture solids like rust and dirt particles over a certain size (usually between 2-30 microns, depending on your filter), and specialised filters can separate some water from fuel, they will generally only trap small amounts before they become overwhelmed. As for emulsified fuel and water, unfortunately the majority of filter/separators can’t tell the difference between this and clean fuel.

These are the situations where Fuel Doctor is the perfect solution.

Service stations do have particulate filters to protect their pumps from rust and other solids. However, these filters do not remove water from fuel, nor do they filter fungal material or microscopic particles of rust, because many of these contaminants are smaller than the micron-rating of service station filters.

Dirty fuel is endemic to the industry and as such can be found in any tank, regardless of size, age, or the company who owns them.

Unfortunately, there are no signs that you are buying contaminated fuel, as the New Zealand fuel industry have removed fuel sight glasses. These sight glasses were used to display the fuel as you were pumping it, so you could check the quality of the fuel you were buying. Due to their removal, most people now have no idea what clean fuel even looks like, so are unable able to assess the quality of the fuel they are buying.

Unfortunately, the first sign you’ll see if you’ve bought contaminated fuel is after the damage has already been done to your fuel system. This damage could be in the form of poor engine performance, lowered fuel efficiency, sooty exhaust, or (if you’re one of the many unlucky ones) the need to replace your injectors, fuel pump, or other engine components.

First and foremost, dirty fuel can cause damage to your fuel system and engine components simply by passing through the system. Microscopic particles of dirt and grime can clog fuel filters and injectors, reducing engine efficiency and ruining the injector spray pattern. Water is vaporised as it passes through the injectors, causing damage to the injector tips, which also ruins the injector spray pattern. In addition, water in your fuel creates the perfect environment for fungi to grow, feed, and defecate throughout your fuel system.

These abrasive contaminants then pass through the system, causing additional, unnecessary wear and tear on the components, which in turn reduces their lifespan and costs you more for repairs and replacements.

The introduction of common rail direct injection in diesel engines has created more opportunities for gum and varnish deposits to form and cause problems with fuel flow, injector spray patterns, and fuel atomisation. The higher pressure also makes it more dangerous for water and other microbial contaminants to pass through the system as they can no longer be simply burned off with a hard run of the engine, nor can the engine be de-coked by pouring water into the carburettor, as with older engines. By comparison, common rail direct injection systems will fail if exposed to less than a shot glass (30ml) of water.

The potential for purchasing contaminated fuel is always present. An alarming amount of fuel storage tanks have some form of contamination or “dirty fuel”. How much and whether it will affect your vehicle depends on a lot of factors: age of the tank, lack of appropriate maintenance, temperature, volume of residual water, where the fuel came from, how long it’s been there, and of course when the tank was last filled. Because you can’t see what goes into your fuel tank, you run the risk of transferring contaminants into your fuel system and causing damage to your engine, every time you fill up.

If you value optimal performance from your vehicle and longevity of your engine, and don’t want the expense of replacing prematurely corroded and damaged components, then you need to use Fuel Doctor to treat and maintain your vehicle’s fuel system.

Fuel Doctor is specifically formulated to do no harm to your tanks, engines, and fuel system components. In fact, one of its primary goals is to add lubrication to your fuel, which reduces pump, injector, and engine wear.

We recommend fitting additional pre-filtration units to all systems. Fuel filters, both standard and aftermarket, play a vital role in keeping your fuel system and engine healthy, and help protect them from foreign matter in your fuel. The reality is though, most fuel filters are designed to filter out solid matter (rust, dirt, and debris) to a certain micron rating. Some have water separators that are great for small amounts of free water, but most have some major fail points.

Water is not a solid and will pass straight through most units that are filters alone. The majority of water separating filters will separate free water but are overwhelmed quickly as they have small catch areas. Without an alarm system, this may make the discovery of water all too late for your engine. The biggest fail point (the one manufacturers don’t tell you about) is that almost all water separating filters on the market today can not separate water once it is emulsified with fuel.

That’s right, the milky emulsification of water with fuel can do exactly the same damage as free water, but many filters cannot distinguish between that and clean fuel and will pass it through to your pump and injectors as if nothing was wrong at all. This is where Fuel Doctor excels and offers you the protection needed to maintain a healthy fuel system and engine.

The benefits of Fuel Doctor include:

• Dispersing water and fungal material from dirty/contaminated fuel
• Lubricating microscopic solid matter that escapes the fuel filter, to allow them to pass through the fuel system safely
• Lubricating the entire fuel system and reducing engine component wear
• Cleaning and preventing gum, varnish, carbon deposits, and other particulate build up in fuel lines, carburettors, injectors, and valve faces
• Minimising exhaust gas recirculation soot deposits
• Maintaining fuel quality
• Providing optimised combustion

Lubricity is the measure of how much a lubricant reduces friction and/or wear and tear on components of, in this case, your engine and fuel system. When lubricity is too low, the components rub together with more force (friction) causing increased wear and damage, resulting in premature parts replacement and higher services costs.

As fuel pressures, running temperature, and performance of engines has increased, so has the need for higher lubricity to ensure that all the required components operate at full efficiency.

Adding the recommended amount of Fuel Doctor to your fuel will ensure you have a high level of lubricity in your fuel system which can extend the life of those components.

When considering the cost of replacement injectors, fuel pumps, and other components, Fuel Doctor is very good value for money as it can prevent damage to these components and extend their service life. When compared to other fuel additives, not only does it treat dirty fuel better, but at recommended treatment rates, Fuel Doctor has been the most cost-effective product in its class for many years.