Reply To: 1931: Shutters Or Thermostat?

[Jim Hycner]

I drill the 1/8″ holes on all of my thermostats. It helps let a little coolant flow at all times but more importantly there is no worries of an air pocket in the head. For the Pierce I had a small recess machined into the water neck so the stat would fit in it nicely against the head.The holes allow the air to bubbles to work themselves out. The thermostat also helps slow the burp out the overflow on deceleration. Still had a little dribble at times and totally eliminated that by getting rid of antifreeze and going to water wetter so there is no corrosion. The antifreeze can foam up and cause it to overflow. Didn’t have to add a drop of water all summer since the changes.”