Radiator cap pressure and how it impacts stress on cooling-system and engine?

Question

OK, if radiator-cap pressure is say 20-pounds as opposed to 18-pounds, won't the overall impact on the engine and cooling-system be more heat/pressure stress???

Sure, the boiling-point will be raised with the higher pressure cap....but so will the pressure in the cooling-system. Also, the engine and cooling-system will be exposed to higher temperatures, with the higher pressure cap, even if that coolant is not boiling......that is still heat the engine and cooling-system have to "tolerate"?????

Doesn't the action of the radiator-cap opening, to release hot-coolant, act as a way to not just get rid of pressure, but also some heat......and isn't this earlier "relief-point" easier on your engine and cooling-system?????

Someone help me here!!!!!!!!!!!!!!

Answer 1

First, you shouldn't put a higher pressure cap on your cooling system than what it's designed for, that way there'll be no issue in the first place.

That said, yes, there will be slightly more stress on the components. The part which will most likely take the brunt are the rubber parts because they are the most flexible. As long as they can take it, there won't be an issue (if all we are talking about is a couple pounds of pressure).

There is something you really aren't taking into account, though, and this has to do with heat. Remember, it isn't the coolant which dictates the heat, the thermostat does. It will be unaffected by more pressure in the system. It will still open when the temperature gets to a certain level and close when it comes back down. More pressure does not necessarily equate to more heat.

The other thing is, under lower pressure, pockets of steam can still form in certain hot spots. With a higher pressure, these pockets will be less likely to form or the pockets will be smaller. This means more coolant is touching more of the block/heads, which means the coolant can do a better job of cooling.