How to Open the Engine Oil Tank Cap?
3 Answers
The method to open the engine oil tank cap is: rotate it 90 or 180 degrees clockwise or counterclockwise to open. Engine oil is referred to as the blood of the engine, and it plays a crucial role in the engine by lubricating, cleaning, sealing, and dissipating heat. Engine oil, motor oil, or engine lubricant is a substance enhanced with additives in base oil, primarily containing anti-wear additives, detergents, dispersants, and multi-grade oil viscosity index improvers. The main functions of engine oil are to reduce friction and wear on moving parts, remove sludge (one of the functions of dispersants) and varnish (detergents) from the engine, neutralize acids produced from fuel and lubricant oxidation (detergents), improve the sealing of piston rings, and cool the engine by carrying away heat from moving parts.
Last time before maintenance, I also wondered how to open the oil cap. Actually, it's quite simple. After the engine cools down, open the engine compartment and locate the round plastic cap on top marked with an oil can or 'OIL', usually with anti-slip serrations. Wipe off the surrounding dust with a dry cloth, then turn it counterclockwise to open—never force it open. The first time I tried, I used too much force and almost damaged the sealing ring. If it doesn't turn, there might be sludge stuck; spray some rust remover and wait ten minutes before trying again. Here's a handy tip: before adding oil, use the dipstick to check the oil level. After adding new oil, don’t start the engine immediately—let the oil settle and then recheck the level to ensure accuracy.
When I took my car in for repair due to abnormal engine noise, the mechanic taught me a daily method to check the engine oil. Open the hood and look for the black cap marked with 'OIL', then twist it counterclockwise like a soda bottle cap. The key is to wait until the engine is completely cooled, otherwise thermal expansion could cause hot oil to spray out. My Japanese car model has a cap with a clip mechanism – just twist until you hear a click to ensure it's properly seated. Remember to regularly clean oil sludge from the thread grooves of the cap, otherwise it may lead to oil seepage over time. During my last maintenance, I found the old engine oil had turned white and emulsified, which was caused by water ingress due to aging of the cap's sealing ring. I recommend checking the engine oil condition by opening the cap every three months.
