Last Updated:

5 Best High Mileage Motor Oils of 2023

Diesel engines provide better performance compared to gasoline engines. However, with great power, comes great responsibility. The maintenance of these engines is considerably more demanding.

Here’s what you need to know:

Despite their MPG advantage over gasoline engines, diesel engines are known to bear some unwarranted problems. Not only are they quite noisy, they are also dirty, smelly, difficult to start in cold weather, and quite sluggish to drive.

But do they have to be all that?

The answer is a definite no. Every engine is only as good as it is treated. For this reason, the easiest and most affordable solution might be investing in the proper diesel oil additive.

Here is why:

Diesel engine oils are more than capable of protecting your engine from the elements. They can provide the much-needed servicing that your engine requires in order to avoid the issues mentioned above.

However, the active ingredients in these engine oils may be soaked into the engine components while performing the functions they were made for. As such, oil additives are best used to top up on these “ingredients”.

Below you can find an analysis of three of the best diesel oil additives:


Castrol GTX High Mileage 20W-50

Quick Specs
  • Rating: 4.9 / 5
  • Brand: Castrol
Check Price on Amazon

Castrol has been in the business for quite a while, and they know how to treat a car right. The GTX High Mileage formula is specially formulated with less phosphorus additive to prevent catalytic converter failure.

It can take you over 7500 miles before a change is necessary. However, if your motor does something next to that of the beast of burden, consider 5000 miles. Its viscosity is an excellent feature. Have a smoky auto? Well, get Castrol GTX before someone recommends a chimney for your vehicle.

This high mileage oil will ward off sludge build up in your engine, protect it from burn-off way beyond industry expectations, seal your conditioners, and most importantly, economize your fuel usage.

Castrol composition includes ACEA and API for volatility specifications.


  • Anti-leaking seal conditioner
  • Extra additives for anti-engine wear
  • Fuel economy; helps save on fuel


  • A little bit pricey

Mobil 1 promises you over 75,000 miles of extended engine performance with the potential to exceed. This is a pure synthetic with the appropriate additives to optimize your engine.

This is a great option for car owners seeking to extend their cars’ lifespans. The company, Mobil, is popular for its great attention to producing quality oils. Not only does this high mileage oil extend the life of your engine but it also improves its performance significantly.

A common issue with engines that have high mileage on them is the accumulation of sludge build-up over time. Mobil 1 can help in cleaning out this unwanted sludge to make your engine run smoother for longer.

The oil can serve almost every make and capacity including SUVs, trucks and light vans. Also recommended for high speed and stop on the go driving. This product is not to be used in the aviation and on the two-cycle engines.

Pennzoil High Mileage Vehicle Oil

Quick Specs
  • Rating: 4.7 / 5
  • Brand: Pennzoil
Check Price on Amazon

If you are out for a great all-around high mileage motor oil, then your best bet is this product from Pennzoil designed specifically for high mileage engines. The unique blend of additives included in its formulation help protect against excessive wear that is associated with the build-up of sludge and old age of the engine.

The additives in the oil also help to keep seals in good condition thereby reducing leaks. It is also processed with cleansing agents to keep sludge at bay!

If you wake up one morning with a pile of ice on your car rooftop, don’t panic if you use Pennzoil. It is designed with low-temperature capability meaning you can still start your car. And as is that is no all; it supports thermal oxidation translating to better performance.

The best thing about this oil, and what I know you will love, is that apart from improving performance immensely, it also helps save on fuel. Quite a neat investment, right? That is not all, it gives you 75,000 miles and can be used with most vehicles including the heavy commercials, passenger vehicles, and SUVs.

It’s, however, a little bit pricey, and you will need to cough up some little coins more if you are a budget guy, but I can assure it will be worth it!


  • Good oil viscosity control
  • Founded on PurePlus Technology
  • Over 75,000 miles of the engine performance


  • May not serve you well with extreme heavy driving

This is a synthetic blend high mileage motor oil that understands the needs of your old engine. Apart from cleaning up sludge build-up and preventing leaks, it also provides the much-needed lubrication to the engine parts to avoid unwarranted wear.

Highly recommended for aging engines. It got a way of bringing life out of your old beast. Thanks to the extra cleansing detergents the manufacturer cared to add. The anti-oxidants built with the substance goes a long way in keeping the engine sludge free.

Most high mileage oils require that you frequently change the oil and MaxLife from Valvoline can considerably reduce oil consumption in between changes.

With a dedicated customer support system, you can comfortably get one and realize an engine rejuvenation. Living on a tight budget? Well, this is one of the most affordable yet effective product.


  • Extra cleaning detergents for rejuvenation of old engines
  • Extra engine wear protection
  • Includes anti-oxidants for a clean engine
  • Seal conditioners hence no leaks


  • May not tolerate extreme temperatures

Are you looking for a product with an exceptional gas economy, unrivaled wear and tear control, optimized engine performance and enhanced cleaning capabilities? Look no further; this is the thing you are looking for.

Even with the most extreme conditions, you can bet on the product for unchanged oil viscosity.

Now, I know what you’re probably thinking. What is a synthetic oil doing on this list? What you may not know about this extended life synthetic motor oil is that it is meant to remain effective for longer periods of time. It does what most other high mileage oils do and does its job well.

Despite being a bit high on the price chart, Amsoil Extended Life Synthetic Motor Oil is definitely worth its value and a great investment for older engines.

What you may not know about this oil is that it is formulated to go for longer intervals between changes, making it quite cost-effective. Come to think of engine oil that can take you for 12,000 miles before changing. Well, this is possible with Amsoil.


  • XL synthetic for better performance
  • Perfect extreme temperature tolerance
  • Up to 12,000 miles change intervals
  • Keeps engines clean and reduces maintenance


  • Not good with aftermarket additives

What To Look For When Choosing A High Mileage Oil

Everything you invest in has to give you a good reason why you ought to throw in your money towards it. The same goes for high mileage oils. Remember that if you are out for these oils, then your car requires tender care. As such, the oil you pick out needs to offer the best care possible to ensure your engine lasts longer.

Here are some of the key areas to focus on:

Age of your motor:

If your vehicle has already done over 75,000 miles, you will need a high mileage engine oil. If your engine is too old, then you got an option up there for 12,000 miles.

Viscosity and temperature:

You will need something that can withstand extreme temperatures and still maintain its viscosity. Also, consider a product with say 20w for this case.


Note that the region you live in may have temperatures or other weather factors that may affect the viscosity of the oil.

Fuel economy: In these times of lean budgets, you will be forced to consider something that will be forgiving in your pocket.


Any product that has extra cleansing additives with it is possibly a yes for it. This guarantees a clean engine with better performance at all times.


Reminds us of the adage “If wishes were horses.” Yes, you cannot afford everything every other time. You will at sometimes be forced to make a trade-off based on how healthy your pocket is.

The older your car gets the more demanding it gets in terms of maintaining it. Choosing a good high mileage oil can help do the trick and you can always pick one from our list.


High mileage oils are made exclusively for engines that are void of warranties and have “high mileage” on them. If you have a relatively young engine, then they aren’t for you just yet.

Also, before you go out in search of a high mileage oil just because you have clocked over 75,000 miles, remember that you cannot fix something that isn’t broken. Yes, your engine is old; but does it behave/misbehave like an old one? Watch out for signs of wear before switching to high mileage oils.

You might also like