Wonder yourself: Is it OK to mix two different fuel brands?

Updated Oct 13, 2020 | Same topic: Handy Maintenance Tips

Different branded gas stations popping at times offering great bargains on fuel per liter. Is it alright to mix fuels from different brands? Read more!

Fuel, whether it be gasoline, diesel or even jet is vital for your car’s operation. The internal combustion engine needs something to, combust, in order to move the car. That is an oversimplified description from your personal car expert (me) but that’s basically how it goes.

It is dangerous to actually run your car completely empty with your fuel pump unable to get fuel to burn. Today I ask a really popular question, seriously, I browse Facebook and Reddit and every single time I find someone asking: Is it alright to switch brands and use different brands of fuel?


So many choices of fuel brands, which to choose?!

Today we’ll be discussing the pros and cons and brushing a little bit on fuel types, octane ratings, detergents and additives in fuels I think you should know. There are more expert tips like these on Philkotse.com for your reading pleasure so make sure you keep your eyes glued as you search for your next car.

There really is no short answer

The short answer to this question? Well before we get to that, there are two prevalent types of fuels sold in the Philippines; Gasoline and Diesel. Gasoline engines go into your good old fashioned cars and some Compact crossovers while Diesel contains more juice and is more energy-dense than gasoline but requires an engine with a higher compression ratio to combust.

total gas station

Once you've chosen a brand you also have to choose fuels

You might say that Gas is Gas and Diesel is Diesel, while this is true, it is much more complicated than that. This much is true when the original product leaves each refinery. The different brands, in an effort to differentiate themselves from each other and add more marketing edge add their own detergents, additives, and chemicals to their product.

Others market theirs as more potent as it cleans the engine as the product combusts itself while others outright market them with a higher octane rating to supposedly make your car go faster. Do these additives and products make your car go faster and more efficient though?

>>> Check out: Brief comparison: Diesel engine vs gasoline engine in the Philippines

Mixing 2 different fuels - YES and NO?

In theory, putting additives on fuel products can make your engine run better and burn the product more efficiently. Brands have spent a ton of their research and development into making products that can help make the engine run smoother or create more horsepower.

They do this by testing their fuels in labs and more popularly in racetracks. Now while their research does net positive results we have to take into consideration the actual car you’re putting the product in.

mustang fox body doing burnout

Octane Rating isn't a magic number to make your car go faster

>>> Also check: What are Fuel Additives and Do They Really Work?

If you notice, Gasoline itself comes in 2 distinct varieties, or let’s just say “flavors’: Premium and Regular. You can tell which is which because the brands themselves will market the premium gasoline with aggressive-sounding words like Blaze, Velocity, Super, Awesome, Epic or other superlatives you can think of.

Sometimes brands won’t give them actual names and just price them higher than regular, that’s when you will know.

hyundai eon on the road

Smaller cars don't need higher octane gas

A fuel’s octane rating doesn’t exactly mean the fuel’s ability to make your car faster. That is the one misconception most car guys fall in to. Remember that inside that engine of yours, small, controlled explosions are taking place and they happen in cycles, in multiple valves and cylinders.

The time in between those controlled explosions is called KNOCK and if you hear something knocking something must be rocking. The octane rating is simply the standard measure of the fuel’s inability to knock during the combustion process.

engine knocking

If your car makes knock-knock jokes, it won't be funny

In smaller displacement cars, you wouldn’t even notice the knock at all that is why fuels with smaller octane ratings are prescribed. There would be no sense in using premium in small cars and any observed improvements are merely placebo effects.

It is, however, required in larger displacement or performance cars as the engines in these cars spin and work at a higher compression rate and higher engine speed. This is when you should NOT use lower octane fuel as the knock would become so apparent that it will destroy your precious car.

>>> Read more: 10 myths about fuel efficiency that every Filipino driver should know

Why different types of diesel?

Over the past 15 years, we have seen a surge in performance diesel fuels as well. Diesel, volume per volume packs more energy than its gasoline counterpart. That energy, however, requires much more work and strain from the engine for it to work. A diesel engine thrives on compression rather than spark plugs to ignite the combustion process.

Hence the burn is less efficient than gasoline and more deposits and product are left during the process. This is why people have rightly considered diesel fuel to be dirtier and more environmentally damaging than gasoline. If you notice the characteristic black suit and smoke from diesel vehicles, that is all unspent fuel being discharged from the engine.

trump in his diesel trucks

Here's what some people think of those Euro ratings on diesel

This is why brands offer you the option for premium diesel and regular diesel. Brands can add more additives and detergents to diesel fuel to ensure proper combustion or at least make the fuel less harmful once it gets discharged through the exhaust.

If you are familiar with Euro Certifications on diesel fuel this means that the particular diesel fuel product complies with strict Euro fuel requirements in terms of how harmful the fuel will be once combusted.

>>> For your information:

Why all these matters

I apologize for the quick science and history lesson, but all these are required for us to answer the question whether or not you should switch brands. Well, here is the quick answer: NO IT IS NOT. You see your car, has a computer. This computer measures your driving style, air quality, according to sea level, and fuel quality.

What it does is it knows what the optimum performance should be according to the parameters it is used to. If you want to reset these parameters you can do a hard reflash by resetting your car’s ECU and it will start learning again. This is why whenever someone who has a small econo car asks me, if they should put premium gas in their car i immediately say no.

If their car gets used to the high octane fuel it will reject the low octane one if you fuel up with it. You can probably do this with older cars that run on knock and levers and switches but fuel injected cars with intricate ECUs should be handled carefully.

kia soul

Your car does have a Soul so pic the best fuel for you

Fuel brands use proprietary additives in their car and if your car gets used to it, it will act weird if different fuels are placed in it. You can fight me in the comments section below if you disagree, but based on personal experience, my own crappy car would always act up if I switch brands.

I thought there was something supernatural about it but I did the research and the explanation I gave you makes much more sense.

>>> More to read: Damages and What To Do When You Pumped The Wrong Fuel

dodge charger demon on the tarmac

Now this car lives on high octane gas only

The moral of the story is if you have a preferred fuel brand. You have to make a commitment to it. Whether it is the larger fuel companies or your Aling Tutays Gas-O-Rama, give your car a break and stick to one.

Roy Robles

Roy Robles


Sleek, Sexy, Athletic and Fast. These are words that were never used to describe our resident claustrophobe Roy Robles. After spending 10 years counting other people's cash in banks, he is just happy to be at Philkotse.com. Catch his articles everyday and make sure to honk if you see him.

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