Will 4S shops say they have changed the engine oil when they haven't?

[AlexisDella]

4S shops generally do not have this situation, many 4S shops already have monitoring functions. The following is the relevant introduction of engine oil: The role of engine oil: That is, engine lubricating oil, known as the 'blood' of the car, can lubricate, clean, cool, seal, reduce wear, prevent rust, and prevent corrosion to the engine. The working temperature of engine oil: The engine is the heart of the car. There are many metal surfaces in the engine that rub against each other. These parts move fast and the environment is poor, and the working temperature can reach 400 degrees to 600 degrees. Under such harsh working conditions, only qualified lubricating oil can reduce the wear of engine parts and extend their service life.

[MirandaLynn]

I've actually experienced this before! Last year, I got my car serviced at a dealership in the eastern part of the city, only to find the oil dipstick pitch black with unchanged levels when I got home. Later, I wised up and started marking the filter housing with a marker before each service. Once, when picking up my car, I noticed the mark was untouched and confronted them on the spot. The technician stammered, claiming they forgot to record it, and ended up compensating me with three free services. My advice to everyone: take photos of the oil level before servicing, request to see the old parts, and ensure the replacement items are clearly listed on the invoice. Nowadays, some shops have real-time monitoring in their service bays—asking to review the footage is the most reliable approach.

[MacJames]

Having worked in the industry for ten years, I've seen many shady practices. The act of charging for an oil change without actually performing it is called 'air filter maintenance,' which often happens during off-seasons to boost performance metrics. The most classic trick is when the drain plug shows no signs of being loosened, and the old oil filter is simply wiped clean and reused. Once, a customer's engine seized, and upon disassembly, we found the oil filter's production date was from two years ago. Nowadays, the law is strict, and getting caught means paying triple the maintenance cost. I recommend supervising the oil change in the workshop—it takes less than 20 minutes. If you're too busy, check the work order for the oil quantity; the amount of new oil added should match the vehicle's manual. If a 5-liter car only shows 4 liters, there's definitely something fishy.

[StRhett]

Last month, I witnessed a new trick while accompanying a friend to defend his rights. A 4S shop's system showed that full synthetic oil had been changed, but the drained oil was as thick as sesame paste. The technical director came to inspect and found that the oil pan screw gasket hadn't been replaced, and the sealant wasn't scraped clean—this proved the oil pan had never been removed! Even more shocking, the warehouse records showed no oil had been requisitioned that day. Later, the shop manager apologized, blaming it on an intern's operational error. Remember: after maintenance, always check the part codes on the settlement sheet—each part has a unique traceable code, making fraud costly.

[LilyMarie]

I heard an inside story from a veteran mechanic when repairing my car: some shops would settle and filter recycled old engine oil, then pour it into original bottles to sell as new. I once saw an apprentice pour a customer's leftover half bottle of oil back into a large iron barrel. It's easy to identify - new oil has a light honey color, while used oil turns black with a burnt smell. After maintenance, remember to check the oil filler port; fresh oil stains indicate a genuine oil change. It's best to bring your own oil and watch them unseal it. Nowadays, mobile apps can check maintenance records. Take photos of the engine bay before and after servicing - only trust it if the screw positions have changed.

[MaggieFitz]

Veteran Driver Teaches You Three Tricks to Avoid Scams: First trick - Take a photo of the oil dipstick scale when the engine is cold before maintenance, as the fluid level is inaccurate when the engine is hot; Second trick - Request to place the used oil containers and filters in the trunk, as recycling them can earn you points; Third trick - Check the mechanic's clothes, as genuine oil changes will leave oil stains on the cuffs. Once, after maintenance, my oil light came on as soon as I drove out, and upon returning, I found they had forgotten to tighten the oil drain plug. Nowadays, high-end cars come with electronic oil life monitoring systems, and a reset showing 100% after maintenance means the oil was genuinely changed. Don't believe them when they say 'the computer resets automatically'—for BMWs, you need to long-press the BC button to reset after an oil change.