i am here for my sister, she owns a 97 Pontiac Sunfire with the 2.4l, its a 5 speed. i was home this weekend, and i heard her car running, not good, so i took it to and auto parts store, to get the codes pulled, they could not do it because they said their was something wrong with the obd port. this is not my main concern, and it worked some time back when we had them pulled earlier.

my main concern, is that when i went to leave its had a very rough time of turning over and did not start, i let it rest and tried again, same thing only this time even slower crank, i let it rest and tried again, nothing, i can hear the starter click and try to engage,but would not even turn the engine at all, and it was turning over just seconds before. i had the battery tested on the spot it was fine, i called my dad to come and tow it home. while he towed me in the parking lot we tried to start it by dropping the clutch in gear, the wheels were completely locked and would not turn at all as soon as the clutch was engaged. i believe the motor is seized. what parts do you think might have been damaged, where can i get good replacements. i need more information on the internals of the engine because i am unfamiliar with it. what size are the pistons, rods, so on and so forth.

also before it broke is was stumbling, but in a regular way, ie the pattern kept repeating, also there was a very audible knock, that happened a few to maybe 5 times a second at idle(i didn't count)
she just had her oil changed last week, and it had apparently been a long time before that, they said it still had oil but that it was very old. also when i looked under the car the solid coolant line that ran from the bottom of the radiator to the engine, was smashed almost completely closed, despite this the temp never got the least bit hot when i drove it.

i hope you guys can help and i hope this gives you what you need, i am going to try to tear apart her engine this weekend, so hopefully you guys can let me know what i need by then.