Corroded thermostat area on merc
 

I changed out my t-stats the other day on my merc 135 and noticed there was some bad corrosion on the cylinder head where the t-stat cover meets the head. Sure enough its leaking some water while running. I tried some high temp silicone which is drying at the moment. I'm not sure if this will work or not. Is there a better fix? I thought maybe some high temp jb weld to build up the small area thats corroded but I'm not sure if it will last. Any ideas would be appreciated.

Well now I have bigger problems. I went to snug down the bolts and sure enough one is stripped. Now what? Can this thing be heli coiled?

get a tap a size bigger and re tap it. Put some anti seize on the bolt next time to keep the corrosion down. High Temp gasket maker should be fine for the pitted surface. Just don't glob it on there so it squeeze out and clog a T stat

try to retap the hole and use a bigger bolt and gasket compund should work fine, thats what i use

If its just the T stat housing BS said has has a bunch of them??