grove cutting tool

[Wildwilly]

I can see your point Frank for a groove to hold sealant. I have worked on & operated many different types of trucks in my career in the oilfield transportation business & I have NEVER seen a Flywheel housing that had to seal oil! The crankshaft oil seal is in the engine block not on the flywheel housing. There is also a starter bolted onto the flywheel housing which may be called a clutch housing also. In the bottom of that housing is an inspection plate through which you grease the throwout bearing & adjust the clutch "free play", also running through the flywheel housing is the clutch shaft with only bushings in the housing that need to be greased & are not sealed. I fail to see your reasoning to seal the mating surface of the flywheel housing to the engine block. IF you ever did happen to seal it all up & did develope an engine oil leak that would fill the housing and make your clutch, now running in oil, totally useless! You wouldn't get too many starts from that starter running in oil either as it is not a sealed unit.
Sorry Frank but I just cannot comprehend sealing a flywheel housing. Please contact me to show me how I am wrong in my thinking.