Conventional Oil Change

Conventional oil is what every engine ran on for most of the last century, and for the trucks and cars built before synthetics became the factory fill it is still a sensible choice. It costs less per quart, it does the job the manual asks of it, and in an engine that has run conventional oil for 150,000 miles there is no reason to change what works. What it does not do is stretch. The interval is shorter, the cold-flow on a January morning in the Carson Valley is slower, and the protection in an August traffic jam on McCarran is thinner than a synthetic's. This page explains who it suits, what the manual says, what sets the price, and how Northern Nevada's climate affects the choice.

At a glance

• Suits older engines whose manual lists a conventional grade
• Shorter interval: AAA puts it closer to 3,000 to 5,000 miles
• The least expensive oil per quart
• Full-service oil change with the maintenance check at all four service centers
• Not a fit for engines whose manual specifies synthetic

Who conventional oil suits

The engine decides, not the driver. If the owner's manual for your vehicle lists a conventional grade such as 5W-30 or 10W-30 with no synthetic requirement, conventional oil meets the specification and the engine was designed for it. That describes a large share of the vehicles built through the 2000s and the work trucks still earning their keep around Reno and the Carson Valley. It also suits an owner who drives moderate miles and comes in on the shorter schedule without fail, because conventional oil forgives neither long intervals nor neglect.

It does not suit an engine whose manual specifies synthetic, which includes most vehicles built in the last decade and nearly everything with a turbocharger or a 0W-20 grade. Putting conventional oil in those engines meets no specification and shortens their life. The technician reads the cap and the manual with you before the first quart goes in; the oil cap guide shows what to look for.

The interval, and why it is shorter

AAA's guidance is that conventional oil and older engines fall closer to 3,000 to 5,000 miles between changes, while many modern engines on synthetic run 5,000 to 7,500 miles or more; the owner's manual sets the actual number for your vehicle. Conventional oil's base stock has molecules of uneven size, which means it thins faster under heat, thickens more in cold, and oxidizes sooner. The additives that fight sludge and acid are used up on a shorter clock. None of that is a flaw if the oil is changed when the manual says; it is a problem only when the interval is stretched.

Severe service shortens it further, and the manual's severe-service column is the one that applies to short trips, dust, towing and extreme temperatures. The interval comparison works through what each number means for each oil type, and the miles versus months guide covers the vehicle that sits more than it drives.

What the owner's manual says

Every manual lists an oil viscosity grade and an API service category, such as API SP for current gasoline engines, and the American Petroleum Institute's Motor Oil Guide is clear that the grade and the drain interval in the manual are what to follow. Conventional oils carry the same API donut as synthetics when they meet the category, so a conventional 5W-30 marked API SP meets the specification for an engine that calls for 5W-30 API SP. What the manual will not say is that a cheaper oil is fine for an engine that calls for synthetic. Where the manual says synthetic, that is the end of the discussion.

Older manuals sometimes list grades like 10W-40 that are rare on the shelf today. The technician will tell you what current grade meets the same specification, and the invoice names what went in.

What changes the price

Conventional oil is the least expensive oil we carry, and a conventional full-service oil change is the entry point on our menu. What moves the price from there is capacity, since an engine that holds more than the five quarts included in the service pays for the extra oil; the oil filter, which varies by vehicle; and any add-on from the maintenance check that you choose to do. Nothing from the check is added without a written price and your yes. The oil change cost page quotes published third-party figures for the Reno area; our own price is quoted at the service center and on the coupons page.

• Engine oil capacity beyond five quarts
• Filter type for the vehicle
• Anything you choose from the maintenance check

Conventional oil in Northern Nevada

The honest case against conventional oil here is temperature. Reno averages about 65 days a year at 90 F or hotter and 122 nights at or below freezing, Carson City 146 freezing nights, Minden 188 (NOAA 1991-2020 normals). Conventional oil thickens more on a cold morning, which means a longer wait for oil to reach the top of the engine on startup, and it thins and oxidizes faster through a hot summer of idling on South Virginia Street. For an older engine driven moderate miles and changed on schedule, it copes. For a vehicle that commutes over the Mount Rose Highway or tows to Topaz Lake, the manual's severe-service column applies and the shorter interval becomes very short.

That is often the point at which a driver asks about a synthetic blend or full synthetic; the comparison page lays out the trade-off without a sales pitch, and either way the engine gets the grade its manual calls for.

Drive in

A conventional full-service oil change is available at Mae Anne Avenue, Longley Lane, East College Parkway and US 395 in Gardnerville, Monday through Saturday, no appointment. Bring the manual if you have it, or let the technician look it up. Older engines that have been treated well are a pleasure to see in the bay; bring yours in.