Reading oil levels involves understanding the dipstick and oil viscosity grades. Let's break down both.
Reading the Oil Dipstick
Accurately checking your oil level requires a few simple steps:
-
Park on a Level Surface: Ensure your vehicle is parked on a level surface overnight. This allows the oil to settle completely in the engine's sump. Checking it first thing in the morning, before starting the engine, provides the most accurate reading (as cited in multiple forum discussions, including Subaru Outback Forums and SwedeSpeed).
-
Locate and Remove the Dipstick: Find the dipstick (usually marked with an oil can symbol). Remove it, wiping it clean with a rag.
-
Reinsert and Remove: Fully reinsert the dipstick, then remove it again to check the oil level. Waiting a minute or two after reinsertion can improve accuracy (as per r/subaru). Ensure the dipstick is correctly oriented; some have markings indicating the correct direction (see Drive Accord).
-
Interpret the Reading: The dipstick will have markings indicating "full," "low," and often a range between. The oil level should fall within the hatched or marked area. (RAM TRX Forum) If the oil is fully covering the dipstick sides making reading impossible, ensuring the dipstick is fully reinserted before removing will yield a better result (r/350z).
-
Add Oil if Necessary: If the level is low, add oil according to your vehicle's specifications.
Understanding Oil Viscosity Grades (e.g., 5W-30)
The numbers in an oil grade (like 5W-30) indicate viscosity. As stated, the number before the "W" represents the oil's viscosity at low temperatures; lower numbers mean thinner oil, better for cold starts. The number after the "W" shows viscosity at normal operating temperature; higher numbers indicate thicker oil.
