How to know if the 4S shop has changed the engine oil?

[AdelineDella]

Methods to determine whether the 4S shop has changed the engine oil: 1. You can directly pull out the oil dipstick, find a tissue paper, and drop the oil on the dipstick onto the tissue paper to observe the color of the oil to determine whether the oil in the engine is new or old; 2. Take out the oil dipstick and hold it at a 45-degree angle, observe the oil droplets under light. If you can clearly see that there are no wear particles in the oil droplets, it is in good condition. If there are many wear particles, it means the oil has not been changed. Engine oil is called the blood of the engine. It plays the roles of lubrication, cleaning, sealing, buffering, rust prevention, and heat dissipation in the engine. Without engine oil, the engine cannot operate normally.

[VonMila]

I've been driving for decades, and there's always a way to solve this problem. Right after picking up the car, pop open the hood and pull out the dipstick to check the oil color: fresh oil is a pale golden yellow, while old oil is black like mud and has a burnt smell. I remember last year after a service, I still smelled old oil in the car. When I checked the dipstick and saw the color hadn't changed, the dealership finally admitted they forgot to change it. Since then, I make them sign the service sheet with the oil change time and oil brand, and I keep the invoice as proof. Engine oil doesn't last long—it's best to change it every 3,000 to 4,000 kilometers. If you don't, the engine will start humming and wear out faster, costing thousands to repair—a total waste of money. Now I've made it a habit to take a photo of the dipstick before servicing and compare it after picking up the car. If I really don't trust them, I'll stand in the workshop and watch the whole process.

[RoseAnn]

From a mechanical perspective, newly replaced engine oil is easy to identify. First, let the engine cool for an hour, then pull out the dipstick to observe: new oil flows quickly, feeling smooth like clean oil; old oil is thick with more sediment, dark brown in color, and may even contain metal particles. Then take a sniff - fresh oil has a slight minty fragrance, while old oil has a pungent odor. If the filter wasn't replaced, obvious stains remain around the side screws. Record the oil level before maintenance, and it should rise slightly after service. Missed inspections are common when 4S shops are busy, so it's recommended to communicate in advance and get written confirmation. Having some basic knowledge reduces the risk of being deceived - for example, checking whether the vehicle idles smoothly after maintenance.

[AdalineAnn]

I was also worried about this when my car was new. Simple steps: after driving home, wait for the engine to cool down, then pull out the dipstick to check. Clear and transparent means it's freshly changed; cloudy and black means it hasn't been touched. Get close and smell it—new oil has a faint fragrance, while old oil has a dull odor. Some modern cars come with dashboard displays for maintenance status, like my app which pops up reminders with updated dates. The maintenance manual specifies the oil change interval—take a regular peek and don't slack off. If the acceleration feels smooth after a few hundred kilometers, it's generally fine.