Discussion Starter · #1 ·
My sons 300 blew the spark plug out while mowing. I reinstalled the plug using a helicoil. Another half hour of mowing and the head gasket failed. I sanded the head on a piece of glass and installed a new kohler gasket, torqueing the bolts to 35 ft lbs. Another hour of mowing and the gasket failed again. I found a replacement head, flattened it and installed another new kohler gasket again torqueing to 35 ft lbs. It failed again. I installed another new gasket but torqued the bolts to 50 ft lbs. Kohlers web site said that was maximum torque for a grade 8 coarse thread bolt. I ran the engine and retorqued after it cooled. The gasket failed within an hour. The engine starts easily and runs great. I can see no flaw in the block. What do I do now?