Why Do 4S Stores Not Advocate for Using a Circulation Machine to Change Oil?

[McGia]

Because during the replacement process, a large amount of transmission fluid is required, resulting in higher costs and longer time consumption. When using a circulation machine to change oil, the oil pump continuously injects new oil into the transmission, while the oil extraction tube continuously draws out old oil from the transmission's drain port. By controlling the equal amount of oil added and drained, the total amount of fluid inside the transmission is maintained. There are three methods to change transmission oil: 1. Gravity oil change: Similar to changing engine oil, this method is the simplest and most economical, generally requiring only 3 to 5 liters of transmission fluid. The downside is that gravity draining cannot completely remove all the old oil, only about one-third of the original fluid. 2. Circulation machine oil change: A transmission circulation machine is connected to the transmission's oil circuit interface, with new oil added to the machine. The new oil pushes out the old oil from the transmission, requiring about 12 liters or even more transmission fluid. The more fluid used, the cleaner the transmission becomes. The advantage is thorough oil replacement, while the drawback is the time-consuming process. 3. Removing the transmission oil pan for oil change: The benefit is the ability to clean the transmission oil filter and achieve a relatively thorough replacement.

[LaRonan]

To be honest, having worked in the auto repair industry for over a decade, I've noticed that 4S shops generally don't advocate for using oil exchange machines, mainly because the process is cumbersome and risky. The oil exchange machine requires high-tech equipment to extract the old oil and circulate new oil, but if the technician isn't skilled, it might stir up sediment in the transmission, clog the filter, or damage the gears, making it less reliable than the traditional drain-and-fill method. The drain-and-fill method simply involves removing the oil pan drain plug to let the old oil flow out naturally, then refilling with new oil—it's straightforward, quick, and cost-effective. Especially for older cars with outdated transmission designs, using an oil exchange machine could lead to more issues, and 4S shops would have to cover the repairs and liabilities—why invite trouble? With our heavy workload, the drain-and-fill method takes just half an hour, saving customers time and money—a win-win. While oil exchange machines theoretically provide a cleaner change, the actual results depend on luck, making the drain-and-fill method more dependable. High risk, low reward—I advise car owners to stick with the recommended approach.

[LaLaura]

From my years of experience working at a 4S dealership, the main reason they don't prioritize power flush oil changes largely comes down to cost. Purchasing that specialized cycling equipment costs tens of thousands, and maintenance is expensive too – unlike gravity oil changes which just require basic tools and labor, offering flexible operations and cost savings. The shop relies on gravity method oil changes for stable profits and quick turnaround, serving more customers per day on average. If they promoted power flush methods, not only would it consume more time and materials, but they'd also need to train technicians to handle risks. If equipment fails or customers complain about transmission damage, the losses would outweigh the gains. Additionally, gravity oil changes follow standardized procedures that are easy for beginners to learn, making shop management simpler, while customers more readily accept the lower price. Personally, I see it like running a restaurant – when the main dish sells fast and brings good profits, who would push complicated alternatives? When customers come for maintenance, I often explain that power flush benefits are minimal with higher risks, recommending the cost-effective and time-saving gravity option instead to avoid wasted time and disputes.

[OLondon]

As a car owner who frequently visits 4S shops for maintenance, I often ask why they don’t recommend using a machine for oil changes. They say gravity oil changes are safer and more straightforward. Last time I went for a transmission fluid change, the technician explained that the machine requires special equipment, is more complicated to operate, and could potentially introduce air or stir up sludge, leading to transmission issues. In contrast, the gravity method, though older, is reliable—just removing a drain plug to let the old fluid out and adding new fluid is simple and low-risk. Price-wise, gravity changes are half the cost and take less time; I only waited about half an hour. From my personal experience, 4S technicians are more comfortable with this traditional method, and during the process, they can also inspect other components like filters or seals, making it more cost-effective overall. If they were to push for machine changes, they’d have limited equipment and less confidence, meaning longer waits and higher costs for me. In short, gravity changes get the job done—why complicate things?

[SimonAnn]

I'm passionate about car modifications and often tinker with transmission fluid changes myself. Dealerships don't advocate for using flush machines, which I think is due to laziness or outdated knowledge. Flush machines can replace the fluid more thoroughly, theoretically extending the transmission's lifespan, but dealerships fear the higher risks—like accidentally clogging fluid passages, which would cost them repair fees. Gravity draining is simpler and quicker, requiring no advanced equipment, so even novice technicians can handle it, making profits more stable for the shops. I've tried gravity draining at home with basic tools, and the results were decent, but flush machines are genuinely better. Dealerships just don't want to invest in training or take responsibility. Many newer cars actually suit the flush method, yet they don't promote it, appearing overly conservative. Whenever I ask, they always claim gravity draining is sufficient, hassle-free, and cost-effective, but this lack of innovation might lose them customers in the long run.

[McJoanna]

From a safety perspective, I often remind people that 4S shops discourage power flush oil changes to avoid malfunctions. The power flush process may stir up debris from old oil. If there are excessive impurities in the transmission, clogged filters, or unstable oil pressure, it can directly damage the drivetrain, causing jerky driving or breakdowns – posing significant risks. Gravity oil changes are different; they gently drain old oil and smoothly refill new oil, reducing risks. Especially for older vehicles or inexperienced operators, power flushes have a higher probability of issues. 4S shops would have to cover repair or replacement costs, which are too high. Personally, I’ve experienced a friend’s car whose transmission was ruined after a power flush, costing thousands in losses. Although the gravity method has a slightly lower oil replacement rate, it’s overall reliable and efficient – prioritizing convenience and safety when you’re on the road. For regular maintenance, choosing traditional methods is both reassuring and economical.