OK.My radiator started leaking and I figured 180000 on the odometer I'll just go ahead and do a cooling system overhaul. Went to put new fluid in and my thermostat housing started seeping a little from the bottom. Do I need a hole in the thermostat to prevent this? I checked the housing and it's not warped.

 

It's very common for the t-stat to slip a bit while the housing is being replaced, preventing a seal. To prevent this, use a bit of gasket sealant (not silicone seal or RTV) to hold the t-stat in place while the housing is mounted.

 

Thanks alot bud.