The others have covered the t-stat question pretty well - don't!

As for the ping/knock, it only costs a little time to SLOWLY run a
pint of water through the intake while keeping the engine at a fast
idle. That will blast the carbon buildup off the heads and help with
pre-ingition for hot deposits. As Mike R. says, you could also run a
pint of ATF through it as well - might even work better - but the
humongous smoke cloud that creates is gonna irritate some neighbors.

--
Will Honea


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I would suggest trying seafoam