Help. I've got a S500 in the shop that came in on the rollback and the serpintine belt was broken. Started the car and blue smoke came out of the exhuast pipe. Compression sounded weird and loud knocking noise sounding like it's coming from the top end. Removed the cam covers and found nothing out of the ordinary. Chains are tight. The car only has 91,000 miles on it. I did a compression check and all but #2 were 185 to 215 pounds of compression. #2 was 100 pounds. Has anyone heard of a bottom end problem with the 119 engine?

Hmmm,
Could it be a bad exhaust valve in head???

Gary

Broken s500 engine
 

Sounds like you need to borescope it and look for signs of broken piston or severe scuffing/seizure.

Someone putting foot in it, low octane gas, could blow it fairly quick