I think I may have caused some confusion. I did some more searching and found this post.

https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=407854

The t-stat bypass and the heater can share the hose to the water pump by installing a tee.

https://www.stovebolt.com/ubbthreads/ubbthreads.php/topics/1182200/1.html

If interested, this is the long discussion about the 261 t-stat that Mike referred to above.

https://www.stovebolt.com/ubbthreads/ubbthreads.php/topics/1164312/1.html

At this point, it looks like I should forget about my ideas in my original post. I should:
  • Replace plug in upper t-stat housing with a hose fitting
  • Move heater hose from lower t-stat housing hose fitting to the new hose fitting
  • Install tee in heater hose that returns coolant to water pump
  • Install hose from lower t-stat housing to new tee

This will provide the bypass and allow me to shut off the heater with the simple valve I have already installed.

Last edited by Gord&Fran; 06/10/2019 6:04 PM.

Gord 🇨🇦
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1954 1/2 ton 235 4 speed