No Compression in cylinder 8 after starter replacement

[zedd0069]

Hello all I need a sanity check. My 05 GX470 was running great. However the starter was intermittently going bad. Last week the starter finally went.. Had it towed to my local mechanic. My wife picked it up it started really rough and then she tried to drive it. All the warning lights came on and it was bucking and hesitating. She turned it around and brought it right back. She didn't make it one block away. Told the mechanic what happened and told them to figure out what they screwed up. Today the mechanic said there is no compression in cylinder 8. When you replace the starter you have to remove the intake manifold to get to it. It is my understanding that no compression could be a bad valve or bad cylinder. Clearly they did something wrong when replacing the starter. Could it be debris from the swap falling into the block or something? An engine does not go from running great to zero compression in cylinder 8 overnight for no reason right?.

 

 

[erikgrad]

Somewhere, on another vehicle forum, I have read about the starter becoming weak and dying because an engine was oil starved in a cylinder (it would be a different make of car entirely, possibly from when I had a Focus?).  Anyhow, that could be what happened here.  The piston in one cylinder is binding from lack of oil, the starter is burning itself up trying to force it to move. Eventually, the cylinder loses all oil, starter finishes itself off trying to turn that cylinder over.  They replace the starter, never bother to check it afterwards, or pretend they didn't notice how rough its running, which is dumb.  Since the cylinder was exposed to the elements, its worth taking it to another shop to be torn down for forensics, make sure they did not drop something in there.  It'd have to be something big, so it's going to be obvious if that was the case.