When I bought my 2001 back in 2014 the thrust bearing was toast, as well as #1 main/rod and #4 rod bearing. Didn't knock until oil got warmed up and thinned out. Eventually figured out that bearings caused false misfires P0300 and P0304 and turned on the SES light/made it flash. So previous owner (I assume) disconnected the SES light, taped over the end of the wire, and traded it in at a new car dealership. I came along and bought it. Talked to a lawyer and problem is how to prove who actually did it - the PO or the dealership - so suit goes nowhere. I doubt the dealership did this because they actually put new brakes and tires on it and I don't think they would have done that if they knew - plus a new car dealership would not risk the bad will for what they would make on an old Blazer. I think they just thought it was exceptionally nice and decided not to wholesale it. Lucky me. So I paid a premium for the vehicle, paid for a new engine, and paid $2500 for a new trans that went out a year later. But it's been about 40K miles since then and if nobody else hits and totals it, pretty soon it won't owe me anything.

 

That's one reason I hate buying used cars, though I would expect better from a reputable dealer.

At least mine didn't run when I bought it, so I was prepared for the possibility that it would need a new engine. I still have my core, so I may tear it down some day to see what all is worn out. My knock kind of came and went, but not with temperature, load, RPM, or anything else. It was just random. When I was pulling the flywheel off of it is when I noticed the excessive end play. I didn't have time then to pull off the caps and look at the bearings, and I haven't cared enough about it since then, lol.

 

Well I tested my theory and took the serpentine belt off... The engine appears fried

 

That sucks. Any chance it could be a loose torque converter or cracked flexplate?

 

How would I check that?

 

Pull the starter out and turn the engine over by hand to check the bolts and look for cracks.