A mechanic shared a social media video showing what happens when you put the wrong type of liquid in the wrong place and how a major error can occur. The video, shared in 2025, has resurfaced on TikTok, showing how easy it is for car owners to make a simple mistake.
The video was shared by TikTok account BackPocketSkills, which says it shares quick fixes, car care, and DIY hacks. However, this video was different. In it, a customer had brought the car in, claiming it had developed a big knocking sound.
The mechanic said the customer had done their own coolant flush at home before the knocking started. The knocking got worse, and the engine eventually seized up, so it was brought in for the shop to take a look.
A seized, knocking engine can be caused by several things. However, in this instance, it was obvious what had happened to the engine when the mechanic started draining the oil. It wasn’t oil that came out of the car, and it turned out the coolant had gone into the wrong place.
What Had the Customer Done to Their Car?
“Customer states they did their own coolant flush at home, and then their engine started knocking and seized,” said the mechanic. “Let’s see what they have in here,” he added as he undid the drain plug underneath the car. It then became obvious what the customer had done to the Ford.
“Oh, that’s beautiful,” the mechanic said as coolant drained from the engine, where it wasn’t supposed to be. “I think he put the coolant in the wrong spot; what an idiot,” he added as it drained out. Clearly, it hadn’t gone into the right spot in the engine, and the mechanic couldn’t believe what they had done. While it is a basic servicing task, not everyone can do it at home, which is why most of us probably take our cars to a garage to have the work done.
If you know what you are doing, then it shouldn’t be a problem. That clearly wasn’t what happened here. We don’t know why the customer put the fluid into the wrong spot. They might have been easily distracted. Or, potentially, they just didn’t really know what they were doing. Regardless, the video drew plenty of humorous comments as TikTok users poked fun at the customer.
TikTok Users Responded in Hood Humor
The comments section was full of humor: “Hello, I put coolant inside my window cleaner; how can I fix that?” said one. “The funniest part about this happening is that the oil cap says oil,” added another TikTok user. There was clearly very little sympathy for whoever had brought the Ford into the workshop. Another user, who appeared to be a mechanic, recounted a similar story in his comment.
“We had a customer top his coolant up through his engine filler cap last week, even though I saw my boss explain to him and say, ‘ You need to take this engine cover off to top up… ‘; he came back,” said user Scott.
The moral of the story is: if you aren’t sure what you are doing, ask for advice or take it to a workshop. Because this cheap coolant flush may now have become a very expensive repair job.