Engine Additives Explained – Myths and True Performance

While engine additives remain one of the most arguable questions in car repair and maintenance, I decided to recap several articles that we've written with our team about additives, cleaning methods, and improving the performance of the engine or various parts of it.

In this article, I will tell you about popular additives and their effect on how your car works. I will tell you about the performance of each commonly searched-for additive. Of course, I will also give you links for further investigation and understanding of car engines.

Performance additives

I will start with performance additives which I personally see as scams. They never work to improve your engine's performance. They rather work to take some money out of your pocket.

Even renowned companies and brands offer their products for "improved friction" between engine components. Like Liqui Moly Ceratec. But they never work and don't show any results which has been proven by independent testing more than once.

Also, the Rislone additive was researched by our team and the results were close to zero.

And it also covers the use of pretty useful products for useless tasks. Such as people trying to use WD-40 to affect the squeaky belt and solve the problem with the drive belt that has to be replaced as soon as possible. Of course, this won't help at all.

Performance additives highlights:

• Efficiency:close to zero
• Availability:lots of brands and products
• Average price: $45
• Way to use:pour into gas or oil
• DIY use:yes
• Experts' advice:only biased advice
• Independent testing:negative
• Consequences:contaminated oil, changed gas properties, loss of money, no effects on performance

Additives for dealing with leaks

Probably, the most common type of additive is the one that helps you get rid of leaks. At least, they claim they will help you.

There are well-known companies that offer such products as Bar's Leaks, for example, or K Seal. Recently, a lot of car owners have asked us about the Blue Devil additive for leak repair. Unfortunately, the answer is always the same - this will not save your engine from leaking coolant.

What's more, these products can easily lead to other problems and cause even more damage.

If you've diagnosed something like a dead head gasket or water pump leak, please don't waste your time and money on sealants and additives promising to solve the issue. They won't help. Only proper repair of your engine will help.

Additives for leaks highlights:

• Efficiency:close to zero
• Availability:agood deal of brands
• Average price: $35
• Way to use:pour into the coolant tank
• DIY use:yes
• Experts' advice:only biased advice
• Independent testing:onlynegative
• Consequences:contaminated coolant, contaminated cooling system, no effect whatsoever

Engine flush additives

Flushing your engine is a procedure that can actually be needed in very specific cases. For example. when the engine hasn't been used for years. Or you've used some extremely bad product instead of oil.

Otherwise, flushing can easily lead to bad results. So, using professionally made or homemade flush products to clean your engine is not usually the best thing you can come up with.

So, if you have a certain specific question about engine flushing, don't ask me in the comments. I stand against flushing as it may only be required in very specific situations and it may be harmful for your engine. It may clog your oil filter in the end or some other function of your engine may stop working properly.

Engine flush additives highlights:

• Efficiency:negative or zero
• Availability:limited choice
• Average price: $85
• Way to use:pour instead of engine oil
• DIY use:possible but complicated
• Experts' advice:mixed advice
• Independent testing:may be positive in some cases
• Consequences:cleaned sludge and buildups may clog the engine

Gas improvement additives

One of the most common types of additives is the product for gas improvement. While sometimes such products can actually be of some use, in most cases, they are made for taking money out of your pocket.

All kinds of octane boosters are a complete scam. Just buy good fuel and you'll be happy with how your engine works. Boosting octane numbers artificially with some additives will give you zero positive effects.

Fuel additives may be of some use in diesel fuel. I don't mean adding oil to this fuel because this is rather a technical additive. However, there are additives that prevent the diesel fuel from freezing.

Gas improvement additives highlights:

• Efficiency:mostly zero
• Availability:a lot of products available
• Average price: $35
• Way to use:pour into the fuel tank
• DIY use:yes
• Experts' advice:mostly negative advice
• Independent testing:negative
• Consequences:injector damage, fuel filter clogging, fuel pump damage, fuel tank damage

Injector cleaning additives

Also, a very popular type of additive is the one that cleans the injectors in your car. Well, at least, it claims to clean the injectors.

Overall, injector cleaning additives are way more effective than anything listed above in this article. But they are not going to repair your injectors. They may help you get rid of some contamination types.

You can use carb cleaner or even prepare a homemade solution to clean the injectors and valves. But keep in mind that everything should be safe for your car.

I can recommend seafoam for almost all kinds of injector cleaning. It's pretty safe and effective. Other products may also be good but please investigate the reviews before you buy something and spray it directly into the throttle of your car.

Injector cleaning additives highlights:

• Efficiency:good if used correctly
• Availability:lots of products and brands
• Average price: $50
• Way to use:spray into the throttle
• DIY use:yes, butmaybe complicated
• Experts' advice:mixed advice
• Independent testing:a lot of positive testing
• Consequences:injector damage ifused incorrectly, exhaust system damage, valve damage

Throttle cleaning additives

One more type of product you may use for cleaning your engine is a throttle-cleaning additive. Again, it can be helpful in some cases when it's absolutely needed.

But before you spray a brake cleaner into your car's throttle just because you read a comment on Reddit or something, think twice. This action may have unexpected consequences.

Also, consider professional throttle body cleaning if spraying the cleaner doesn't help much.

Throttle cleaning additives highlights:

• Efficiency:good if used correctly
• Availability:limited number of products
• Average price: $45
• Way to use:spray into the throttle
• DIY use:yes, butmaybe complicated
• Experts' advice:mostly positive advice
• Independent testing:a lot of positive testing
• Consequences:injector damage ifused incorrectly, exhaust system damage, valve damage

Catalytic converter cleaning additives

Unfortunately, catalytic converters aren't eternal and they can get clogged. So, the manufacturers of chemical products decided to earn money manipulating this problem and offer a lot of products for "cleaning catalytic converters".

You may have heard about CataClean or some other products with very similar names. But they usually don't work that effectively. While they can help you in some rare cases, usually, these products are not efficient.

A lot of people use homemade solutions such as lacquer thinner. But the problem is that they can damage other components in your car and aren't recommended for use either.

Catalytic converter cleaning additives highlights:

• Efficiency:close to zero
• Availability:limited number of products
• Average price: $80
• Way to use:spray into the throttle
• DIY use:yes, butmaybe complicated
• Experts' advice:no positive advice
• Independent testing:negative testing results
• Consequences:damage to a lot of expensive components, no effect on catalytic converter

Lifter additives

There are two really common situations when car owners remember about lifter additives: lifter noise and a stuck lifter. For example, a lot of drivers tend to use Lucas Oil products to make lifters silent.

But do these additives really help? Well, this is highly doubtful. There are cases when seafoam-based cleaning products helped solve several minor lifter problems. But when it comes to various marketed additives, they have pretty much zero effect.

Also, stuck lifters will never be cured by additives. Unfortunately, only professional repair will solve the problem. Sometimes, the lifters will just need to be replaced with the new ones.

Lifter additives highlights:

• Efficiency:close to zero
• Availability:limited number of products
• Average price: $65
• Way to use:add to engine oil
• DIY use:yes
• Experts' advice:no positive advice
• Independent testing:negative testing results
• Consequences:spoiling of oil properties, engine damage in the long run, no effect on lifters