Thermostat?


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By Ol Ford Guy - 13 Years Ago
OK, I've searched the archives, and have been over educated...I think.  My car ,with new motor, is running a little too warm, so I'm changing  my new 160 thermostat to a high flow 170.  My new thermostst, from CASCO, has a very small hole in the flat portion on the surrounding metal near the outside diameter.  I read that people drilled little holes to improve performance.  Should there be a hole in the gasket aligned with the hole in the thermostat?  Should the hole in the gasket and thermostat be alligned with the small notch in the cast thermostat housing? 

Thanks,

By DryLakesRacer - 13 Years Ago
Not sure where that hole would line up or if it matters. As I understand it it was to make sure "some" water circulated thru the radiator with the thermostat closed.

I too had a problem with the new 292 in my 56 running warm. The fix was to put a plug in the 1/2" bypass hose and drill a 1/8-3/16" hole in the plug. Too much hot water from the engine was being recirculated back thru the engine with the thermo open. Now everything works great. It doesn't heat up quite as fast but runs a lot cooler, never over 1/2 on the guage in traffic or 90 degree day. I can tell when the thermo is cycling by slight guage movement. GreenBird gave me the fix and I thank him for it....Good Luck..JD

By Doug T - 13 Years Ago
The little hole goes at the top of the thermostat when installed.  It is intended to bleed air out of the engine as the coolent is added and fills up the motor.  I concur with almost blocking off the small coolent recycle line with a blockoff plate and a small hole again as an air bleed during filling.
By GREENBIRD56 - 13 Years Ago
I believe that your new t-stat must be like the one on the right below???

In which case it is hard to decide where to put an "auxillary" bleed hole? There is usually a small bleed port in them that can be enlarged - and then you try to make sure its at the top-most position you can place it.

The high flow outfits - Robertshaw type units - are drilled as shown below.

 

By Ol Ford Guy - 13 Years Ago
I found that when the little hole in the thermostat was on the top, it was aligned with the notch/path in the cast housing.  The hole was just far enough in so the gasket didn't block it off. 

Thanks for the comments.