zero pressure cooling system

[Chamberpains]

I have always (13 years) ran a "faulty" coolant reservoir pressure cap to vent the pressure build up for zero pressure system. I usually cut the rubber gasket in the cap to vent the pressure but keep the coolant from splashing out. I've never had a boiling problem. I've done this with a couple Detroit 60's, Cummins n14 and now ISX cm870. I also dont hammer up hills and use the fan to cool down before shutdown. Other than that your normal fan on setting will keep your temps in a safe zone. If not you have other problems.

I don't get hot coolant leaks, minimal cold leaks but you have to watch dry rot sets in slow so you should replace all hoses and clamps when you see signs of it happening.