Will the oil decrease if the car is parked under the sun?
3 Answers
If a car is continuously exposed to the sun, the oil will evaporate, with a small amount potentially escaping through ventilation holes. Here are the relevant details: 1. Evaporation: Evaporation is a physical phenomenon that occurs with all liquids. The higher the temperature, the faster the evaporation rate. Liquids with lower density evaporate more easily than those with higher density. Gasoline and alcohol have similar densities (gasoline being slightly lower), making them both prone to evaporation. 2. Sealing: In theory, gasoline will not evaporate if it is sealed in an airtight tank. However, in cars, fuel is stored in fuel tanks, which are not completely airtight and have some ventilation to the atmosphere. Therefore, gasoline stored in a car will inevitably evaporate to some extent.
Having driven for over a decade, I've noticed that when a car is left under the sun for extended periods, the engine oil doesn't usually decrease without reason, but the oil level may sometimes appear to fluctuate. This is because high temperatures cause the oil to expand when heated, making the dipstick show a higher oil level when parked; once cooled, it may seem lower. Actual oil loss is mostly due to leaks or aging seals, allowing small amounts of oil to evaporate or dry out from the heat. In summer, I make it a habit to check the oil level every two weeks, especially after parking in the sun, to ensure it's within the normal range. Additionally, high temperatures can thin the oil, reducing its lubricating effectiveness, so I always recommend switching to seasonal oil earlier, preferably using summer-specific oil. Moreover, prolonged sun exposure increases the overall engine temperature, accelerating wear on other components, such as rubber hoses under the engine cover, which may crack and lead to more severe leaks. Regular minor maintenance is far more cost-effective than dealing with problems after they arise.
I'm a car enthusiast and love studying these little details. When a car is parked under the scorching sun, the volume of engine oil changes due to thermal expansion and contraction. If you check the oil level after parking for a while, it may appear falsely high—this doesn't mean the oil has actually decreased. In a properly sealed system, the total amount of oil remains relatively constant. However, under high temperatures, a minimal amount of oil can evaporate, especially if the car's crankcase seal is compromised or the oil cap is loose. This can result in slightly lower dipstick readings after the car has cooled down post-drive. I often remind myself to monitor oil pressure and levels more frequently in hot summer weather—at least every three weeks. By the way, high temperatures don't just affect engine oil; they also increase tire pressure, raising the risk of a blowout. So, after parking my car in the sun, I always take a few minutes to check the oil level and tire pressure to avoid safety oversights. Overall, don't worry about oil mysteriously disappearing—focus on regular maintenance and timely oil changes to keep your car in top condition.
