Description of Problem: 1999 mercury cougar 2.5L V6 automatic trans: I was driving down the road and suddently lost power. the engine was still running but sounded alittle rough so i turned it off. then it wouldnt start. after having it parked for a couple months i started looking ant it and notice that the starter is spinning the flexplate but the harmonic balance isnt turning. it does turn by hand with a socket. after talking to a mechanic i was told a used motor would run $1500+. he said i broke the crank or timing chain? i thought if it was the timing chain the harmonic balancer would still turn, he didnt agree. and i thought it was unlikely that the crank would just break driving down the road. Do you have any idea what it could be? or how i can narrow it down. not alot of autoshops where i live and the one shop im pretty sure just wants my money cuz i dont know much about the problem. if the flexplate or bolts broke off would that cause my problem? Any help or advice would be great thanks.
Actually, the mechanic you talked to is probably wrong
I think the flexplate is cracked
What’s going on is that the starter is turning the ring gear, but since the flexplate is cracked, the engine isn’t being cranked over
Check out this picture. It explains it much better than I can
Please keep us updated
If the flexplate is broken it would probably be making an awful racket when the starter turns it. Is it?
If the flexplate isn’t broken, and the starter turns the whole plate, but the harmonic balancer doesn’t turn, then a broken crank is a possibility. So is a broken key for the balancer pulley. I agree with you that the broken timing chain theory is odd. It’s the cams that wouldn’t spin.
How about you pull the plugs and find out if all of the pistons are going a) when it is cranked with the starter and b) when you turn the balancer by hand with a socket. If you turn the pulley with a socket did you look to see if the flexplate is going too?
I’ve seen a crankshaft break just before the rear main bearing.
I had a GM vehicle come in where the owner thought the transmission failed as the engine would run but the vehicle wouldn’t move when put into gear. When I went to remove the transmission, I turned the crankshaft by hand to bring the flexplate around to remove the bolts from the torque converter. Well, when I rotated the crank the flexplate didn’t rotate.
So what started out to be a transmission replacement turned into an engine replacement instead.