A very interesting thread indeed.
Well, I correctly remember three instances when I learnt something new about cars.
Incident 1 - It was around the year 2000, when a friend's had picked up a used Fiat Uno. One day, we friends were going on a joy ride and had stopped over at a garage to get the car checked for something. With the bonnet open I was trying to understand all the parts I could see in the engine bay. After a while just out of curiosity I started opening all the oil reservoirs I could see in front of me to have a peek inside. Finally I came to a cap which was right in the front and center from where engine bay starts. I tried opening it, but it was a bit tight and after some effort it loosened up and I could hear some sound as if air was leaking out. That's when a friend realized what I was doing and stopped me immediately. The mechanic who was standing next to me had his eyes wide open and asked me what I was trying to do?? And I was like nothing, I am just trying to see what is below this cap. That's when my friend told me that its a radiator cap and should never open it specially after the engine is hot and if I had managed to open it I would have surely burnt my face.Boy, was I lucky that day and learnt one of the most important hazard under the bonnet.
Incident 2 - Now, sometime in 2003, the same friend who had the Uno had sold it and picked up a Tata Indigo. One day the Indigo developed a puncture at the rear tyre in his building. We thought no big deal, we can change it to the spare tyre ourselves. So we jacked up the car and tried opening the four nuts. Now to our surprise the spanner provided by Tata would not fit any nut. We tried many times and it just would not fit. Finally gave up the idea of changing the tyre ourselves and packed up everything and gave a mouthful to brand Tata for providing the wrong size spanner. After a few months at a tyre shop, we were seeing how the guy was changing the tyre on the Indigo and to our surprise the spanner provided by Tata fitted properly this time. We were like this is pure magic, but at closer inspection realized that he had pulled out the wheel cap before opening the nuts with the spanner. We like Duh's were trying to fit the spanner on something which resembles a nut on the wheel cap.
A image of how the wheel cap on the Indigo back then used to look like.
Incident 3 - This one was on our first car, which was a used wagon R. We had picked up the car in 2006 and my mom and sister who were in Kerala had no clue about it. The idea was to surprise them, by taking the car to pick them up from the railway station at Thane. Since I had limited driving experience my elder cousin came with me and was to get off somewhere before we reach Thane station, as he had some work there. On Ghodbunder road some where by brother asked me to stop on the side, as he wanted to drive the car for sometime. So we both exited the car and since the A/c was on, we shut the doors. Once we crossed sides, my brother tried opening the door and it would not open, so I tried opening the door and it would not open too. When we checked inside, we found that the doors were locked and the lock lever was all the way down. That is when we realized the horror of having auto locks. Now, we are standing out of the car in the baking sun and the A/c is running without anyone inside the car. The only options now was either to seek a mechanic's help to open the door or get the spare remote from home. Now, we were in a secluded section of the ghodbunder stretch and plus we were were far away from home to get the spare remote, plus I was getting late as I had to pick up my mom from the station. With no option left, we decided to break the passenger glass to gain access to the car. With a heavy heart picked up a rock and tried breaking it, but no luck. Finally, my brother managed to get a hammer from a shop in the distance and we broke the glass in the second attempt. Now, we were back in the car but there were glass pieces all around and no way I could go to pickup mom with a car in this state. She would have got some shock of her life with our first car and the state I had put it in. Plus the thought of facing dad back at home was just sending shivers down my spine. So located a Maruti service center on the way and landed up spending 1100 bucks to get a new glass fitted. The service center guys asked me what had happened and I told them the full story. One of them also made a sarcastic statement and said that good you did not brake the rear quarter glass thinking it is a smaller glass, as it costs more than double. Also, to rub salt over the wound, they told me that you should have called us before breaking the glass as you could have opened the door using a scale, just like the RTO towing guys do. Only if I had time that day to think and use my mind and even if I did, wonder where would I have found a scale to open the door on ghodbunder road. Well, in the end I did manage to reach in time at the station to pick up mom and was the whole family surprised to see the car. But till this day only I and my brother actually know what all we went through that day and we have a good laugh every time we talk about that incident.