How Much Difference is There Between Cold and Hot Engine Oil Dipsticks?
2 Answers
There is a quarter difference between cold and hot engine oil dipsticks. The oil dipstick is located on the top or side of the engine and has an orange or red pull ring. The oil dipstick is a simple-structured liquid level gauge that directly displays the oil level in the oil pan, with clear upper and lower limits. The detected oil level should be between these limits. The correct way to use the oil dipstick is: 1. Check the oil dipstick after the car has been parked overnight or for half an hour; 2. Ensure the correct oil level position is observed, checking both sides and using the lower reading as the accurate one; 3. Frequently inspect the oil dipstick to ensure timely oil replenishment; 4. Pay attention to changes in oil quality; 5. Be alert to any malfunctions of the oil dipstick.
I can relate to this issue as I often check my engine oil myself. When the engine is cold, all the oil drains back into the oil pan, so the dipstick reading will be higher. After the engine warms up, some oil remains circulating inside the engine, reducing the oil level in the pan, which results in a lower reading. Typically, the difference is between 4 to 8 millimeters, roughly equivalent to a quarter of the scale between the upper and lower limits on the dipstick. The key is to measure under the same conditions for accuracy—I prefer checking it cold after leaving it overnight, as the oil level stabilizes then. Significant discrepancies might indicate oil burning or leaks. For example, if the oil level is below the minimum mark when the engine is hot, it’s dangerous as the engine might suffer from insufficient lubrication. Regularly checking the oil condition is crucial to avoid the hefty bill of an engine overhaul.
