Latest scoop on Anti-freeze???

[CapitalTruck]

Dex-Cool works fine as long as you keep an eye on the level. Don't let it get to low as the vapors in the systems become corrosive. Keep 'er full and you'll be fine.

 

[Kawiguy454]

My understanding of how a t-stat actuates is there is a sealed capsule in the center basically a piston inside and a wax based substance with a known expansion/temperature coefficient. When the fluid around it heats up it begins to push the actuator and open. T-stats go bad when the capsule leaks and no longer actuates. I think it would be random where it is upon failure. any mechanism to force it to open position would IMO add a fail point. I will also add that it is possible to overheat an engine with the t-stat stuck fully open also. The coolant does not have enough time in the radiator to shed its heat.

If you look at a t-stat there is a bypass hole in it so a small amount of coolant continuously flows. Back in my BB Chevy hot-rod days it was common to open that hole a little bit for a little more thermal cushion. If the t-stat stuck shut and you saw an engine temp light or temp gauge and turned off the motor it wouldn't have been damaged.

 

[440Magnum]

Originally Posted By: Kawiguy454
My understanding of how a t-stat actuates is there is a sealed capsule in the center basically a piston inside and a wax based substance with a known expansion/temperature coefficient. When the fluid around it heats up it begins to push the actuator and open. T-stats go bad when the capsule leaks and no longer actuates. I think it would be random where it is upon failure. any mechanism to force it to open position would IMO add a fail point.


Exactly. And when the wax pellet seal does start to break down and wax begins seep out past the plunger, it frequently causes the T-stat to just bind part-way open. It really is pretty random, and the "failsafe" just adds an extra way for the stat to wind up locked wide open, which is also a failure.

Originally Posted By: Kawiguy454
I will also add that it is possible to overheat an engine with the t-stat stuck fully open also. The coolant does not have enough time in the radiator to shed its heat.



Old myth, long ago debunked. Some engines develop stagnation patterns inside the cooling jacket when the flow rate gets too high so they'll locally boil coolant, but its never true that the coolant "spends too little time in the radiator to shed heat." That would violate the laws of thermodynamics.