Can You Mix Synthetic And Conventional Motor Oil?

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Can You Mix Synthetic and Conventional Motor Oil

You’ve been traveling for several miles and realized that your car requires an oil top-up. You stop in the nearest garage only to find conventional oil. So can you mix synthetic and conventional motor oil? Yes, it’s advisable in emergency cases.

These oils have base oil plus additives though synthetic motor oils are more superior to conventional oil. Its additives help to clean engine deposits. Synthetic motor oils have fewer impurities than convection, thus protecting the engine components well from excess friction.

Conventional oil has more impurities that increase friction, thus breaking down the oil faster. That means even if these oils have compactible components, combining them will only weaken synthetic oil performance.

Should you get an oil change?

If you fail to follow the manufacture’s oil change recommendation, overheating of engine parts will occur, thus damaging the vital components. Replacing an engine will be a severe hit to your wallet. That’s why watching these vital signs is essential. They include

1. Excess vehicle exhaust

You will never see the tailpipe of a modern car releasing a visible exhaust unless the exhaust system has a problem. If you check the gasket and other components and are okay, the issue could be the oil. Check the oil condition and change it immediately.

2. Abnormal vibration when idling

While shaking when idling may come due to different reasons, among the reasons includes the old oil. That results from the friction that occurs due to the rubbing engine parts resulting from a lack of lubricant. So, add engine oil immediately.

3. Low oil level

Your engine may have an oil leak that may cause the oil level to reduce. So, if you start smelling burnt oil, or see engine smoke, check the oil level. If it’s low, replace or repair damaged parts and refill the oil.

4. Increased engine noise

Oil will attract particles with time and cause friction in the engine parts. So, once you start driving, the engine parts will rub each other producing noise. Stop the car once you hear these noises and replace the oil.

5. Slicks under your vehicle

If you park your car overnight and find a brownish yellowing stain on the surface, there are chances of an oil leak. Repair the leaking part and refill the oil.

6. Indicator light

If you see the indicator light illuminating on your dash panel, that’s an indication that something is wrong. You need to check the oil level; if it’s less, top it up.

What’s the difference between synthetic motor oils and regular oils?

New car owners struggle to find the right oil for their cars. Some believe that all oils are the same; the main difference is the brand.

Regular oil is commonly known as conventional oil, while others call it mineral-based oil. Synthetic oils are superior to regular oil due to the reasons stated below.

1. Their make

Synthetic oils are man-made oils and comprise alkylated aromatics, polyalphaolefin, plus synthetic esters and additives. Regular oils originate from petroleum and also have some additives. 

2. Performance

Synthetic oil has fewer impurities, thus produces less friction and can withstand extreme temperatures. It doesn’t break down quickly, thus giving you an extended replacement period compared to the regular oil. Synthetic motor oils offer more engine efficiency compared to conventional oil.

3. Cost

Since synthetic oil is superior to regular oil, synthetic oil is more expensive than regular oil.

Why do people mix synthetic oil with regular oil?

People mix synthetic and regular oil due to two major reasons; Optimization and emergency. Some people clearly understand the benefits of synthetic oil but are not willing to pay the high cost. So, they mix these oils to get the benefits that come from synthetic motor oils.

Others require changing the oil when traveling. They check in the nearest petrol station and find the convectional oil. They opt to use it before getting to the garage to flush and refill with the correct oil.

Can you mix synthetic transmission fluid with regular transmission fluid?

Combining two incompatible fluids is dangerous to your car. You should always find out to know the effect of the fluid you intend to combine and put in your vehicle. Luckily, Synthetic transmission fluid is 100% compatible with the regular transmission fluid; thus, you can mix them.

When should you avoid mixing synthetic oil with regular oil?

Whenever you have the opportunity to use the right oil, avoid mixing the two. Remember, you can only combine the two in an emergency scenario, and once you get to the mechanic, flush the blended oil and refill with the right type.

The benefits of synthetic oil vs conventional oil:

Below are the benefits that come with synthetic oil compared to what you enjoy with conventional oil.

1. Engine protection

Both oils lubricate engine components, thus reducing excess friction that causes overheating.  But once exposed to high heat, convectional oil breaks down quickly, thus exposing the engine. The synthetic doesn’t break down quickly, therefore offers prolonged protection to your engine, allowing it last longer.

2. Engine cleaner

Synthetic motor oils have lesser impurities compared with the convention thus don’t form sludges like conventional. Synthetic additives clean the deposits, thus keeping the engine clean.

3. Protects engine in extreme temperatures

Convection is okay in normal temperatures but not in extreme temperatures. Regular oil tends to stick together during cold weather and takes longer to flow, thus offering poor protection to your engine.

It evaporates or even breakdown easily when the temperature is hot, thus leaving the engine exposed. Synthetic is excellent in all temperatures since it flows well and doesn’t break up quickly, even with a turbocharged engine that gets very hot.

How to choose the best motor oil for your car?

There are a few factors you need to consider when choosing oil for your car. They include

1. Location

You need to consider the weather and the nature of the terrain. If the place has extreme weather and has uneven terrain, then synthetic oil would be great. Remember, you require oil that is not affected by climatic change. It should also flow smoothly to lubricate the engine as you ride through rough terrains.

2. Vehicle

Every car comes with a manual that explains to you the type of oil that you require. Stick to the instructions and use the recommended oil.

3. Driving habit

Do you like driving roughly, or do you drive slowly and smoothly? You also have to consider if you drive for many hours or just to the nearest town and back. Rough and long driving requires synthetic oil.

Full synthetic vs synthetic blend: which Is better for your car?

Full synthetic oil is a mixture of synthetic base stock topped with additives that optimizes its performance. Synthetic blend, on the other hand, is the synthetic base stock topped with conventional oil that reduces its performance. That means full synthetic offers higher performance and protects your engine better than synthetic blend oil.

Synthetic vs conventional oil: which is better for your car?

Although synthetic has a higher cost than conventional, it remains the best in the market. It’s highly refined and is of high quality. It’s highly stable and doesn’t acidify or oxidize easily compared to conventional oil.

How do you know what type of oil to use in your vehicle?

The manual comes with instructions concerning the oil to use, depending on your location. You also get instructions concerning the suitable viscosity.

Why it’s not a great idea to mix synthetic and conventional oil?

Although combining both oils seems harmless to your engine, avoid mixing them unless it’s an emergency. Synthetic, as explained above, is superior and has additives that clean the engine of any deposits. It also has fewer impurities, thus less friction. Once you combine the oils, you will destabilize synthetic oil, thus lower its efficient performance.


1. Is it bad to mix synthetic oil with regular oil?

You can comfortably mix the two since they are both compatible. But remember, you will be weakening the synthetic oil.

2. What happens if you mix synthetic oil with regular oil?

Once you mix these oils, synthetic oil will get destabilized, thus reducing its efficiency in protecting the engine.  

3. Can you mix semi-synthetic oil with regular Oil?

Yes, you can mix them since the components that create them make them compatible.

4. Can you mix different brands of synthetic motor oil?

Yes, you can mix different synthetic motor oil bland. For instance, if the level of Mobil 1 reduces, you can comfortably top up with AMSOIL.

5. Can you mix fully synthetic oil with a synthetic blend?

Yes, though it will reduce the excellent performance of the full synthetic oil and make you replace the oil sooner.


If you don’t have synthetic oil to top up to the low levels, there is no harm, topping with the conventional oil. But remember that the conventional oil will only interfere with the synthetic performance, thus replacing the oil sooner. So, unless you don’t have any other option, stick to the recommended oil and avoid mixing them.

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