Do Fuel Additives Work? Oil vs fuel vs additive

There are many aftermarket additives on the market, which you can dose into your fuel tank, or oil sump. Many of them make big claims. These vary from reducing fuel consumption and engine wear, to solving problems without extensive dismantling. Some are valid; others are less so.

Should I use an additive?

Check your vehicle handbook for the carmaker's advice on additives but do not be surprised if you find that your car's manufacturer is vehemently against them.

Yet, we have heard of even main dealership workshops being loyal additive users. Therefore, this general blanket additive ban may be for legal liability reasons, rather than technical merit.

Advice differs also between chemical companies. For instance, many blenders claim that additives may contain chemistry that undermines the additives within their engine oil. Yet, other corporations that produce both engine oil and additive supplements say that there is no such issue.

Therefore, do your research carefully, so you can make an informed decision. Look for independent reviews. Most cars possess a social media ownership group, so you can gather and share advice, especially tips involving additives that can help minimise the effects of a common foible.

What are the different categories of additives?

For combustion-engined cars, you can buy a variety of additives. Fuel additives are the easiest to handle, because they are dosed into the fuel tank. Oil additives are poured into the appropriate component's oil supply.

Intake additives tend to be for experienced DIYers, or garages, where an additive is injected into the air intake system. Coolant additives can help flush out old deposits, remove contamination, or even plug leaks.

What are the different types of fuel additive?

Fuel additives can perform a variety of tasks, dependent on the type. Octane (petrol), or cetane (diesel) boosting additives bolster the fuel so it can burn in a way that helps the engine extract more power.

Fuel injector cleaners help shift deposits that may prevent the engine from burning fuel efficiently. You may find different types of additives. For instance, direct injection cleaner tends to be formulated to dislodge the more stubborn deposits that are present on injectors that are cited within the combustion chamber.

Some fuel additives either help to either prevent diesel particulate filters from blocking, or to clear a partial blockage. Exercise caution, if the filter is clogged excessively. This blog provides further information. The removal of carbon build can also be beneficial; turbocharger cleaners are useful to clean variable vane mechanisms to prevent them from seizing.

Some fuel additives provide extra lubrication. For instance, lead-replacement additives help to lubricate the valve seats on classic cars. Some diesel additives assist with lubricating the high-pressure fuel pump. This GEM blog contains some more information on the topic.

Especially as modern British petrol contains up to 10% ethanol, the fuel deteriorates quickly over time. Eventually, the fuel can age to such an extent that it will not burn satisfactorily, and the engine will either run poorly, or even refuse to start. Fuel stabilisers are ideal for cars that are used infrequently, because they preserve the fuel for longer. Petrol-powered garden equipment, such as lawnmowers, can also benefit from fuel stabilisers, when stored over winter.

What are the different types of oil additive?

Oil additives perform a variety of functions; it all depends on which ones you select. The most common ones are stop-leak additives, which help swell elderly and hardened rubber seals to eradicate oil leaks. Additives that help control oil consumption on older engines thicken the lubricant to reduce the chance of it passing into the combustion chamber.

Additionally, anti-wear additives help to bolster the oil's protective qualities in both engines and transmissions. You can also find additives for transmissions and axles, too.

Oil flush additives tend to be most beneficial on modern engines, which are added before the old oil is drained out, to help reduce the chance of the new oil being degraded prematurely.

Do additives work?

Some of them do; some do not. Much depends on the quality. Other variables include using the appropriate additive for the task. For instance, using a fuel additive to clean the air intake is unlikely to yield a positive result.

Are additives safe to use?

Provided that you buy additives from a reputable brand and a trustworthy source, you reduce the risk of causing damage to your car, or causing a safety issue. A good indicator is if the producer has a UK-based technical helpline that you can contact.

Read the instructions carefully. Adding too much additive might even be dangerous. We have heard of owners overdosing diesel particulate filter cleaner additives into the fuel, causing the filter to overheat and melt. In extreme cases, a vehicle fire has resulted.

Therefore, use additives for their intended purpose. Never be tempted to think that more additive means a greater chance of solving the issue.

What additive should I buy?

When asking this question, consider carefully what you wish to achieve. Additives are available to help repair issues, without dismantling. Especially if your car is coming towards the end of its days, an additive might be a cost-effective option to extend its life for a little longer.

Such additives include those that plug leaking cylinder-head gaskets, or radiators. Yet, a physical repair may be a better option for a higher-value car. Some intake, or fuel system, cleaning additives are so effective that professional garages recommend their use as part of regular servicing, for preventative maintenance. Again, we must emphasise that you should select well-established brands.

Garages may recommend additives and for good reason. As modern engines are prone to clogging up internally with contamination, and their finer tolerances mean that they are less capable of tolerating this internal build-up, such advice is worth considering. Even so, prioritise quality and always read the instructions.

Additive top tips

• Check your handbook, or warranty, before using any additives

• Read any instructions on the packaging carefully

• Use any additive as directed. Never overdose.

• Select recognised additive brands, especially those with UK support contacts.

• Buy through recognised outlets; unknown shops on online marketplaces can be risky.

• Wear gloves, when handling any chemical.

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