What is the optimal position for the oil dipstick when the engine is cold?
2 Answers
There are two marks on the oil dipstick, indicating the minimum and maximum oil level heights. Generally, the oil level should be between these two marks. Based on empirical values, the oil volume between these two marks is approximately one liter. Here are the relevant details: Function: The oil dipstick is used to measure the static height of the oil level, thereby reflecting whether the engine oil volume is within a reasonable range. A standard oil dipstick will have clear upper and lower limits, and it is sufficient to ensure that the measured oil level falls between these limits. Ideally, the oil level should be at the midpoint. Note: It is important to remember that more oil is not necessarily better. A higher oil level actually increases engine resistance (since the crankshaft needs to continuously agitate the oil in the oil pan for splash lubrication). Under ideal conditions, the oil level should be maintained slightly below the midpoint, where engine resistance is minimized, fuel consumption is lowest, and lubrication performance remains stable.
I always check the dipstick myself before each maintenance. The cold engine check is the most accurate because all the oil has flowed back into the oil pan. Park the car on level ground, turn it off for half an hour, pull out the dipstick, wipe it clean, reinsert it, and then check—this reading is the real deal. There are two horizontal lines marking the upper and lower limits; the oil stain should be in the middle to upper range, ideally around three-quarters of the way up. Don’t exceed the upper limit, or the engine will struggle to breathe and may leak oil; don’t go below the lower limit either, as insufficient lubrication will cause parts to grind noisily. Last time, I took a shortcut and checked with a hot engine, and the dipstick showed low oil. The mechanic said it was a misjudgment, and I ended up making an unnecessary trip. Remember this little trick, and your engine will last many more years.
