My '02 x-type, 2.5, has a terrible single knock coming from the center cylinder in the back three of the motor. It developed one night my daughter and I were coming home. We were in cruise control running about 90, and I did't hear it, I was enjoying the ride. My daughter said it sounded like a bike chain coming off. That's when I noticed the automobile slowing down, cruise control was disabled and we kept slowing down. We had a little power, but not a lot. When I would step on the gas, the motor would knock. We didn't hit anything nor did we blow-up anything. Since we were about 20 miles from home and it was 2:00 a.m., I was not about to stop with my daughter in the car. Too many horror stories are developed at night in the middle of no-where. The more I would try to accelerate the more the motor would knock. It sounded like it was out of oil. Finally we made it to an exit, i pulled off and finally the auto quit. I was waiting for the motor to catch on fire. We finally had cell phone service and called a friend. Meanwhile I was checking fluid levels and the oil was so hot it wasn't showing up on the dipstick, I thought it was completely empty. My daughter and her friend went and bought some oil and while they were gone I checked everything I could on the auto. I found no leaks, nothing hanging down, nothing broken. As the motor cooled down the oil started showing up more on the dipstick. I did put a quart of oil in it and the automobile started. Confused about this, I started driving, but the car had no power, all the warning lights were on (amber, red and it was in limp mode). As I got closer to the house, I figured people would be calling the police because of the clanking noise coming from the car. I figured the motor in my x-type was shot so I might as well drive it as far as possible. We made it home but the funny thing is my daughter was in the car behind me and said that it never smoked once. We got home and went to bed. The next morning I bought oil, filter and changed it. there was no water in the oil just a few very tiny metal particles. The coolant was fine, so I started the x-type.
The Jaguar fired right up, but there was the knocking in the motor. The motor idles smooth, the motor does not smoke. I've changed the oil three times so far. I've checked everything, I am not a mechanic, I just tinker around on different types of cars. My Jaguar has been in the garage for the last two years. I've been waiting on it to fix itself, hahaha. I've talked to tons of mechanics and they all have different conclusions as to what the problem could be. The last one that a mechanic told me that it sounded like a "keeper ring" came off a valve and that is what's making the knocking noise..
Sorry for such a long story, but that's the only way to explain what happened that fateful night. If anyone does have a question or an explanation, please comment.
danny