Is it okay to mix high mileage oil with regular oil? (2023)

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Is it OK to mix high mileage oil with normal oil?

Yes. There is no danger mixing synthetic and conventional motor oil. However, conventional oil will detract from the superior performance of synthetic oil and reduce its benefits.

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Can you mix high mileage with full synthetic?

Myth: Full synthetic oil is not good for high mileage cars or older vehicles. The myth is rooted in the idea that synthetic oil is “slipperier”—lower in viscosity, or not as compatible with seals and will therefore leak or leak more in places conventional oil might not. Again, completely untrue.

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Is there really a difference between high mileage oil and regular oil?

Regular oils will provide protection for your engine, but high mileage oils are specifically formulated with specific conditioners, seal compatible conditioners, antioxidants, detergents and additives to combat the issues that high-mileage vehicles often experience as they age.

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Is it OK to mix synthetic oil with regular oil?

Yes, you can safely mix synthetic and conventional oil. All motor oil, whether synthetic or conventional, is a combination of base oils and additives.

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Can high-mileage oil damage an engine?

High-mileage motor oil doesn't hurt and it could prevent leaks from starting. Most vehicle manufacturers would say it's normal for an engine to consume some oil between oil changes.

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At what point should I use high-mileage oil?

The bottom line is that high-mileage engine oils are designed for engines that are beyond their warranties and have 60-, 80-, 150,000 miles. Use it if you see a leak or notice rattling.

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Does it hurt to mix full synthetic with synthetic blend?

Synthetic oil is entirely compatible with regular oil and synthetic blend oil.

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What happens if you mix synthetic oil with full synthetic?

Mixing different types can destabilize your motor oil, reducing its efficiency and affecting your engine's performance. The smartest choice is to stick with the oil type and oil change intervals recommended by your car's manufacturer and visit your local car care experts for affordable services.

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Should I use high mileage oil or full synthetic?

As a rule of thumb, most new cars require synthetic oil. Older cars generally run well with conventional oil, unless your vehicle has more than 75,000 miles on it, in which case high-mileage oil is recommended.

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How long does high mileage full synthetic oil last?

In general, though, modern cars can manage 5,000 to 7,500 miles between oil changes. If your vehicle calls for a blended or full synthetic oil, you can push that to 10,000 miles.

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What is the best oil for older engines?

While contemporary engines are designed internally to live on such lightweight lubricants and improved sealing technology prevents leaks, we believe vintage engine are normally better served by heavier 10W-30 or 20W-50 synthetics.

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Why you shouldn't use full synthetic oil?

Risks of Using Synthetic Oil in Older Cars

This is because many synthetic oils contain esters, which are organic compounds mixed with alcohol. This particular combination can be extremely rough on seals within the engine, which can cause the seals to wear down and begin to leak or burn oil.

Is it okay to mix high mileage oil with regular oil? (2023)
Will high mileage oil stop oil burning?

High mileage oils contain additives and seal enhancers that reduce leaks (both internal and external). It's possible that after an oil change or two, the leaking could stop. This has the potential to reduce oil spots in your driveway and on burning oil in older engines.

Why use high mileage synthetic oil?

High Mileage Oil Can Help Extend Engine Life

It seals piston-ring gaps and cylinder-wall valleys to keep contamination to a minimum. It protects the engine from collecting lubrication-crippling sludge. And it prevents corrosion from moisture and/or acids that may find their way into the engine.

Is it OK to use thicker oil in high mileage engine?

A: Yes. This is a practical method to improve oil pressure in an older, high-mileage engine. The slightly thicker oil film from the heavier base weight oil — 10W — can help protect worn engine bearings as well.

Is high mileage oil good for older cars?

They wear down, and older vehicles with higher mileage need a little extra boost to keep things running smoothly. That's where high mileage oil comes in! Just as you can take steps to stay healthy later in life, you can give your car high mileage oil to help curb wear and tear related to old age.

What are the disadvantages of synthetic oil?

A few disadvantages of synthetic oil to be aware of include: Probably the most glaring downside of synthetic oil is the cost. The price of synthetic oil is around two to four times the price of conventional oil. Synthetics may be more prone to additives precipitation during cold storage conditions.

Will mixing synthetic and regular oil damage engine?

So, can you mix synthetic oil with regular oil? Yes. If it's something you do only occasionally, mixing shouldn't damage your engine.

How do I know if I need synthetic blend or full synthetic?

If you are on a budget then synthetic blend would be best for you. While full synthetic is more expensive. Full synthetic oils do not degrade as fast as synthetic blends. Full synthetic will need to be changed every 10,000 to 15,000 miles depending on your vehicle.

What additive keeps engines clean?

Dispersants. Dispersants are mainly found in engine oil with detergents to help keep engines clean and free of deposits. The main function of dispersants is to keep particles of diesel engine soot finely dispersed or suspended in the oil (less than 1 micron in size).

How long can you go over with synthetic oil?

Synthetic blends hold up longer and won't break down, even after 5000 miles of driving. Newer cars also have better filtration systems, allowing you to safely drive 5000 miles between oil changes. If your car holds more than the typical 5 Quarts you may also be able to safely run 5,000 mile oil changes.

Is synthetic oil good for older cars?

It protects better, performs better, and lasts longer, and it's no longer made with a chemical compound that could hurt older vehicles. Modern synthetic oil is safe to use in all types of vehicles, ranging from new purchases to classics to aging not-so-classics.

Are high mileage oils worth it?

If oil consumption increases with the car age, switching to high-mileage oil could help to reduce it and eventually save you cash. If you don't notice any of the problems mentioned above and the oil consumption remains the same, there's probably no need to switch.

What happens if you mix 2 different engine oils?

Can oils of different grades be mixed? The good news is that mixing different types of oil it will not harm your engine in any way in the short run. Most synthetic and semi-synthetic engine oils are based on regular oil and are compatible.

Is it OK to use thicker oil in high-mileage engine?

A: Yes. This is a practical method to improve oil pressure in an older, high-mileage engine. The slightly thicker oil film from the heavier base weight oil — 10W — can help protect worn engine bearings as well.

Can you mix Mobil 1 with mobil1 high-mileage?

Yes. Mobil 1 is fully compatible with conventional motor oils, semi‐synthetic motor oils and other synthetic motor oils, should it be necessary to mix them. But the superior performance of Mobil 1 will be reduced by diluting it.

Can you use high-mileage oil instead of synthetic?

As a rule of thumb, most new cars require synthetic oil. Older cars generally run well with conventional oil, unless your vehicle has more than 75,000 miles on it, in which case high-mileage oil is recommended.

Can mixing oils mess up your car?

Short answer, no. In the short term, it's okay to mix oil especially if your engine is running low on oil. Any oil in the engine is better than no oil at all. So, if you're in a pickle where you need to top up your engine oil, go ahead.

Will the wrong oil damage my engine?

Engine Damage

Your engine could still be susceptible to damage, and it's a good idea to have it looked at by a mechanic. Using the wrong engine oil can cause the metal parts of your engine to shear, making additional noise, and leaving metal shavings in your engine oil.

Is high mileage oil thicker or thinner?

High mileage oils contain viscosity modifiers that are durable and won't diminish over time. This causes the oil to stay thicker for longer periods of time, helping protect your engine parts.

How often should high mileage oil be changed?

You may be wondering “how often should I change my oil if my car has high mileage”? If you have a newer car with 150,000 or 200,000 miles you likely should also change your oil every 3,000 miles. If you burn more than 1 quart of oil or your oil is very dark before you get to 3,000 miles it's likely time to change it!

Should I use Mobil 1 high mileage?

Mobil 1™ High Mileage motor oils are designed for engines with over 75,000 miles and are recommended for all types of modern gasoline-powered vehicles, including high-performance turbocharged, supercharged, multi-valve fuel injected engines found in passenger cars, SUVs, light vans and light trucks.

Is Shell engine oil better than Mobil?

Mobil and shell are both good options. Go for what is cheap. Both have a good additive pack. Mobil1 (0w-40) has a higher viscosity Index while Shell helix ultra is lighter as per specs on paper.

What's the difference between Mobil 1 and Mobil full synthetic?

Mobil 1 is part of our ultimate line of advanced full synthetics. It uses the latest in additive and base oil technologies that provide superior protection, and outperforms Mobil Super Synthetic. It meets both GM's stringent dexos1* and Europe's ACEA performance standards.

Is there a difference between high mileage synthetic oil and regular synthetic oil?

The main difference between regular motor oils and high mileage ones is typically in the additives that have the task of minimizing the roughness on the engine's metal surfaces by filling the tiny microscopic cracks thus creating smoother mechanical surfaces.

How long does high mileage synthetic oil last?

Unlike regular car oil, synthetic oil is more refined which can lower friction, reduce engine sludge, and increase engine performance. It's recommended that you change synthetic oil every 7,500 – 15,000 miles, depending on the vehicle and the brand of synthetic oil used.

What is the difference between high mileage oil and full synthetic oil?

High Mileage with MaxLife Technology is created using a blend of natural and synthetic oils as its foundation, while Full synthetic High Mileage with Maxlife™ Technology uses an even more robust base of entirely synthetic oil. Either way, they contain similar additives to address the problems related to wear.


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