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What Is High Mileage Oil And Do You Need It?

An odometer on a high mileage car. Is high mileage oil a necessity for vehicles with high miles? Is high mileage oil worth the extra cost? Here's why high mileage oil is a good idea for cars with over 75,000 miles.

Tasked with shopping for oil change supplies, the number of engine oil types and varieties can be mind-boggling. Conventional oil, synthetic oil, oil for cars newer than 2012, high mileage oil, detergent oil, recycled oil and more — is it just hype or marketing? Ask for advice and you’ll likely be further confused or conflicted, and car maintenance is complicated enough, but does your vehicle need high mileage oil?

What’s in Your Engine Oil?

A jug of engine oil isn’t just mineral or synthetic oil but contains additives, some up to 30%. These additives improve certain oil characteristics, suppress weaknesses and add new beneficial properties. This 5W-20 high mileage motor oil contains additional additives specific to high mileage engines.

  • Extra Detergents keep particles in suspension for the oil filter to strain out. Some minor engine deposits may also be cleaned out.
  • Seal Conditioners cause gaskets, O-rings, and seals to soften and swell, which can improve engine sealing, minimizing or stopping external leaks, such as from crankshaft or camshaft seals, and oil consumption, such as from weak valve stem seals.
  • Anti-Wear Agents bond to metal surfaces, improving the effectiveness of mineral and synthetic oils and preventing excessive wear.

This sounds like some great stuff, but it’s not for all engines.

What’s High Mileage, Anyway?

People used to think 100,000 miles was excessive, but when late-model vehicles run over 300,000 miles with only basic maintenance, defining high mileage vehicles has become somewhat fuzzy. It depends as much on the year, make and model of the vehicle as it does how it’s driven and maintained. Indeed, 75,000 miles on a city car or on a delivery vehicle is nothing like 150,000 miles on a commuter car. A poorly maintained 75,000-mile engine might have worse internals than a well-maintained 300,000-mile engine.

High mileage oil can't repair things like these spun crankshaft bearings.When considering high mileage oil, it’s important to note it can’t solve major problems, such as major oil leaks, blow-by, power loss, rod knock or piston slap. These can only be solved by repairing or replacing failed components. On the other hand, its enhanced additive package may clean up minor deposits and improve internal and external oil sealing, improving lubrication and stopping minor seepage and oil burning. Again, high mileage oil is no magic bullet, but it can keep a well-maintained engine running longer before it needs new seals.

To keep your high mileage vehicle on the road longer, consider the benefits of high mileage oil, specifically formulated for engines with more than a few miles on them. It can’t solve every problem, but it can help in certain circumstances. After one or two oil changes — always change your oil on time — you might notice some improvements. If not, the engine may require repairs.

Check out all the maintenance parts available on NAPAonline or trust one of our 17,000 NAPA Auto Care locations for routine maintenance and repairs. For more information on high mileage oil, chat with a knowledgeable expert at your local NAPA Auto Parts store.

Photo courtesy of Flickr.

Benjamin Jerew View All

Ben has been taking things apart since he was 5, and putting them back together again since he was 8. After dabbling in DIY repairs at home and on the farm, he found his calling in the CGCC Automobile Repair program. After he held his ASE CMAT for 10 years, Ben decided he needed a change. Now, he writes on automotive topics across the web and around the world, including new automotive technology, transportation legislation, emissions, fuel economy and auto repair.

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