Hi all -
I thought I would post this situation here and see if anyone has any reccos. I recently had a water leak on my '78 yanmar YSM-12 diesel. Its running off 5 yrs since a rebuild (new head, piston, liner, pumps, injector, etc) ~ 170 hours. The engine runs great and has never overheated. So I pulled the head this weekend to replace the head gasket and found the tear in the gasket that matched up with the external leak. No oil or water leaks into the oil otherwise. Engine power is fine. I did notice a hairline crack in the cylinder liner that runs with the stroke of the piston - very slight crack that looks almost like a discoloration. It does not come up to the head as there is a separate ring where the block meets the head. It runs down about 1.5 inches.
I decided to reassemble everything and she started up on the second try and ran great all day. No water or oil leaks whatsoever. Any thoughts or ideas on why this would happen? Should I go for another tear-down to replace the liner? The liner was in otherwise great shape.
Thanks - Rob
I thought I would post this situation here and see if anyone has any reccos. I recently had a water leak on my '78 yanmar YSM-12 diesel. Its running off 5 yrs since a rebuild (new head, piston, liner, pumps, injector, etc) ~ 170 hours. The engine runs great and has never overheated. So I pulled the head this weekend to replace the head gasket and found the tear in the gasket that matched up with the external leak. No oil or water leaks into the oil otherwise. Engine power is fine. I did notice a hairline crack in the cylinder liner that runs with the stroke of the piston - very slight crack that looks almost like a discoloration. It does not come up to the head as there is a separate ring where the block meets the head. It runs down about 1.5 inches.
I decided to reassemble everything and she started up on the second try and ran great all day. No water or oil leaks whatsoever. Any thoughts or ideas on why this would happen? Should I go for another tear-down to replace the liner? The liner was in otherwise great shape.
Thanks - Rob