Top radiator hose

[iajjpop]

On my ''T'' with a 305 G.M. motor [bored 30 over and a R. V. cam] When I drove it and shut it off , the top raditor hose would suck down[a dent in the hose] start it up it would go back O K. Here last Feb. I put a new 600 Holley on it, hasn't done it since. What made it change??? Its O. K. by me.

 

[railroad]

Could be just the time of the year, temp wise, or the carb is fatter or leaner and changed the temp of the engine enough to affect the expansion and contraction in the cooling system. I would guess the thermostat is closed and the water in the radiator cools faster than the engine coolant and creates a contraction. Usually the lower hose collapses while the pump is trying to pull the water out of the radiator into the engine. This can cause cooling issues. The lower hoses usually have a coil of spring wire in them to prevent this. If you temp gauge is happy, I would not worry about it.

 

[sstock]

If it bothers you, remove the thermostat housing and drill a 1/16" hole on the outside of the thermostat disc, that will allow pressure to equalize.
Steve

 

[Mr. Fixit]

If it bothers you, remove the thermostat housing and drill a 1/16" hole on the outside of the thermostat disc, that will allow pressure to equalize.
Steve

Don't all t-stats already have a small hole in them on the outer ring? Everyone that I have ever bought has??