Should the Forester use 30 or 40 engine oil?
2 Answers
The Forester can use 30 engine oil, which has relatively low viscosity and is suitable for Japanese cars with precision-engineered structures like the Forester. As for 40 engine oil, it has higher viscosity and is more suitable for German or American cars. The Forester is a compact SUV produced by Subaru. In terms of body dimensions, it measures 4640mm in length, 1815mm in width, and 1730mm in height. In terms of power, the Forester offers options including a 2.0L hybrid system, a 2.0L naturally aspirated engine, and a 2.5L naturally aspirated engine. For tire specifications, the Forester provides choices of 225/55R18 and 225/60R17. As for the transmission, all Forester models are equipped with a CVT continuously variable transmission.
I've been driving a Subaru Forester for years, and the oil viscosity depends on the model year and climate. For newer Foresters, like those from 2020 onwards, the manual recommends 5W-30 synthetic oil because it has lower viscosity, ensures quick cold starts, reduces engine wear, and improves fuel efficiency. Older models might use 10W-30, but higher viscosity oils like 10W-40 aren't recommended unless specified in the manual or for high-temperature regions. The numbers on the oil label—the one before 'W' indicates cold-weather flow, and the one after 'W' shows high-temperature viscosity; 30 is suitable for most conditions, while 40 is too thick and may increase resistance, affecting acceleration. Subaru's horizontally opposed engines are sensitive to oil—using the wrong type can lead to increased noise or higher fuel consumption. I change the oil every 5,000 miles, choosing API-certified brands and avoiding mixing different viscosities. If you've lost the manual, check the official website or ask the dealer—don't guess.
