Overheating 340

[Robert Mcdougall]

I've changed my cooling system by putting in a recovery bottle and cap. Then I found the aluminium thermostat housing was leaking and pitted. Replaced that with a cast iron housing, this needed a smaller flanged thermostat. Now I 've found the temp is sitting higher on the gauge, and gets hotter after running hard. Will the housing cause this? or is it the recovery system not suitable. Is it better to use the aluminium housing for the aluminium manifold?

[JVMopar]

What temp t-stat did you put in. And what Lb radiator cap did you put on it. An over flow/recovery bottle on your cooling system shouldn't have an negative affect on your cooling. I guess I would have used a 160 or 170 degree t-stat. I have a 160 in my truck. And I would use a 16lb radiator cap. A cap that holds less pressure will cause the car to run hotter.

[djswwg]

You should also compare the old stat with the new one. You said the diameters were different. Be sure the new one will actually pass the same amount of coolant as the old one, and check to see if you have a higher temp. stat than the old one. The overflow kit you installed only allows you to keep the rad full(er) because you don't need the room for expansion in the rad anymore, so it can't negatively impact operating temps.........djs

[PLUM CRZY]

Running hot? One thing I've found in the past, when rebuilding an engine everyone wants to punch the bore size out to the maximum. What is not taken into account is wall thickness of the cylinder. When cylinder wall thickness becomes thin, the heat from combustion transfers to the coolant much quicker, hense running hot. In a stock block heat will dissapate through the cast iron a little more before it hits the coolant. I know this theory is out there, but think about it it makes sense.
One more thing, i had a buddy flush his coolant system and he mistakenly bought coolant that was already a 50/50 mix. He didnt realize it and diluted the mix with water another 50%. Needless to say the freeze/heat protection temps were way off!