The 4Runner has a reputation for running past 250,000 miles, and the 4.0 V6 under the hood is a big reason why. It's a tough, port-injected engine that mostly wants to be left alone and fed clean oil on time. The catch is that "on time" isn't one number. It depends on the oil in it and how the truck lives. Here's how the schedule actually works.

The Mileage Numbers

Toyota's schedule splits into two tracks, and knowing which one you're on sets the interval:

• On full synthetic under normal driving, roughly every 10,000 miles or 12 months
• On synthetic under severe service, closer to every 5,000 miles or 6 months
• On conventional oil in older 4Runners, about every 5,000 miles
• Whichever comes first, miles or months, since oil ages sitting still too
• The 4.0 also holds a large sump, so a short-changed fill runs dirty faster

The maintenance minder on newer trucks tracks some of this, but it doesn't know how dusty your last trip was or how long the truck sat, so the calendar and your own read still matter.

Why Severe Service Is the Real Schedule for Most

Here's the part owners miss. Toyota's severe-service schedule isn't just for hard use. It covers ordinary Bay Area life. Short trips that never fully warm the oil, stop-and-go commuting, towing a trailer, summer heat, and off-road dust all put you on the 5,000-mile track, not the 10,000-mile one. Most 4Runners around here live a severe-service life whether the owner realizes it or not, so erring toward the shorter interval is the safer bet.

What Stretching It Costs the V6

Push the oil too far and it thickens, darkens, and loads up with grit. It stops flowing quickly into tight clearances, so parts wear. It bakes into sludge that clogs oil passages and the pickup screen, and a starved passage is how even a durable engine finally lets go. The 4.0 is forgiving, but every over-long interval trades a little of its long life away.

Why the Oil and the Shop Matter

The 4Runner calls for a specific viscosity and spec, not whatever's cheapest on the shelf, and the wrong oil can cause the exact wear you're trying to avoid. A shop worth using runs the correct oil, resets the maintenance minder, and treats the change as a chance to look the truck over, catching a seeping gasket or a tired belt while it's minor. Look for a place that shows you what it found instead of padding the ticket.

How We Handle It

When a 4Runner comes in, we ask how you drive to set the right interval, change it with the correct oil and filter, and put the truck on the lift for a once-over, checking for leaks, worn belts and hoses, and anything starting to wear. Then you get a straight read on where the truck stands and when it's due back.

Keep the 4Runner Going

Clean oil on the right schedule is what carries these trucks past the numbers that stop other engines. Bring your 4Runner to Driven Auto Care of Castro Valley and we'll set your interval and change it right. Call to schedule an oil service.