I recently picked up a 99 OBS 2.2 AT 126K timing belt and water pump done at 104K
It ran a little rough sometimes, but most of the time it was ok. The check engine light was on when I got it, but went out shortly afterwards. There are no codes stored on the computer.
I was driving about 50mph and it started losing power, I was on a busy road with nowhere to pull over, the shoulder was filled with a mountain of plowed snow, so I tried to keep it going until I could get off the road, by the time I got to where I could pull over, I had it floored just to keep it moving. The engine was still quiet at this point. As soon as I let up on the gas, it died. I tried restarting it and it cranked but sputtered and stumbled and would not restart.
The temp gauge never went over half (don't know if it's accurate or not), and the heater blew hot air the whole time. The engine compartment smelled really hot. The oil level was good. I added about a quart of coolant.
After I let the car sit for about 45 minutes, I tried to start it again. It fires right up, but it sounds like someone is taking a hammer to the engine. I tried moving the car to a better place, a parking lot instead of the side of the road, and it had very little power.
After having it hauled home on a flatbed, I pulled the accessory belts, still the same noise. I pulled the timing cover and the noise didn't get any louder. The timing marks are still lined up, and I put a stethoscope on every non moving part under the timing cover, including the bolts on the idlers, Noise isn't coming from there.
I pulled spark plug wires one at a time, it changed the idle of course, but that's all. No one plug wire made a difference in the sound other than slowing it down a little.
What do you guys think? main bearing?