Almost lost my engine - learn from my stupid mistake.

[Scott98]

Last Sunday I decided to repack my front wheel bearings and change the oil in my car. While changing the oil, I noticed the oil filters I purchased at the dealership didn't have the copper or steel washers included. I also noticed they had two rubber o-rings. I just grabbed one of the o-rings and put it on the filter housing cover. It was tighter than usual going on but I didn't pay much attention to it. I finished changing the oil, shut the hood, finished my wheel bearings and took off.

As I was driving down the road later, I couldn't remember whether I had tightened the bolt in the oil pan. I pulled over and sure enough, it was only partially in. I tightened it up there with tools I had in the trunk - disaster averted.

Monday afternoon as I was sitting in rush out traffic, I smelled something (always the first indication of trouble) looked at my gauges and noticed my oil pressure was fluctuating between 1 & 2. I slipped the car into neutral and gave it some diesel to see if the gauge would rise. It did not. I immediately turned the engine off and coasted into the median. I got out and looked at the car and noticed engine oil everywhere! I got back in and called a tow truck - the traffic was too heavy to stand out there and try to figure out what happened.

I had the car towed to a mechanic. The next day I called him and his first words were: "Who changed your oil?" As it turns out, the o-ring I used was too small and oil was gushing out of the top of the oil filter housing. The car had almost no oil in it by the time it got towed to the mechanic. Luckily, the mechanic was able to fill it back up with oil and the car ran fine. It looks like I got REALLY lucky. Who knows how the engine will hold up in the long term but it looks like I shut it down before anything bad happened.

Moral: Never rush through ANY type of job on the car. After changing your oil, always start the car and observe everything to make sure there are no leaks. Had I done this simple step, I would never have had this problem. It turns out Mercedes had put two different size o-rings in the box and I grabbed the wrong one. In a way I am really mad at Mercedes for packaging their oil filters like that but it really was my fault for not taking my time and double checking my work.

Scott