What is the oil change interval for synthetic oil?

There’s not single oil change interval for synthetic oil that applies to all engines

Everyone seems to think that using synthetic oil automatically means you can extend your oil change interval. Not so fast, bud. As I’ve said over and over in all my blog posts, your oil change interval for synthetic oil is determined by the carmaker according to your driving habits and how long the oil has been in the crankcase.

Here’s an example: This Toyota technical service bulletin warns about oil change intervals.

Toyota Technical Service bulletin #T-TT-0262-13 titled OIL VISCOSITY APPLICABILITY AND CHANGE INTERVAL GUIDE

Here’s the gist of what the bulletin says; starting in 2010 Toyota started using synthetic 0W-20 oil in many of their car models and certain engines and upped the oil change interval recommendation to 10,000 miles for most vehicles (except the 2TR-FE engine which had to stay at 5,000 mile intervals).

HOWEVER, if you read the new recommendations, you’ll see there are LOTS of caveats. For example, Toyota states that:

• For engines where Toyota specifies 0W-20 synthetic, using that oil viscosity is MANDATORY. These engines have variable valve timing and using a different viscosity oil can mess up the VVT and set a check engine light.

BUT even if you use 0W-20 synthetic, the bulletin goes on to qualify the 10,000 mile oil change interval. For example, you must drop down to the 5,000 mile oil change interval if you:

• drive the vehicle off-road

Off-roading reduces oil life

• drive on dirt roads

Driving on dirt roads decreases oil life

• tow a trailer

Towing a trailer reduces oil life.

• drive short trips when outside temps are below 32°F

Cold starts reduce oil life

• •idle the engine

Stop and go city driving reduces oil life

All these recommendations follow this post on my blog that talks about HOW you drive as an important factor in when to change your oil.

What’s the oil change interval for synthetic oil in older vehicles?

Let’s say you have a 2001 vehicle that didn’t require synthetic oil and now you want to use it. Can you automatically double the oil change interval? Nope. Older engines had larger bearing clearances and different emissions equipment. Each of those affect oil life.

The only certain way to know how long synthetic oil lasts in your older vehicle is to remove a sample and sent it off to Blackstone Labs for an oil analysis.

©, 2016 Rick Muscoplat

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