Allpar Forums banner
1 - 1 of 1 Posts

1 Posts
Great article, and I've got a question regarding my particular modified application. I'm running a big block Mopar 440 in my 2002 Dodge Dakota, and I am trying to determine which cap is best suited for my particular application. I am using a new/replacement 2002 Dodge OE radiator and heater core, and a coolant recovery tank from a '98 Jeep Cherokee.

According to the parts store application guides, 2002 Dakotas list for a 20 psi full-pressure (FP) cap/system and recovery tank (spring-loaded recovery valve), and the 70's big block (and the 98 Jeep) list a 16 psi PP cap/system and recovery tank (weighted recovery valve). I am inclined to 'match the cap to the engine'. To further buddy the waters, I have the option of either a PP or FP cap in the 16 psi range.

The kicker is there are 16 psi PP and FP caps available for my radiator...but I am inclined to think I should match the cap to the engine, which means going with a partial-pressure system, but I can also use a full-pressure caps for the same application.

Seems the PP system is 'easier' on the cooling system in general, and I cannot find any solid reason to go with a FP system. "Boiling points" come to mind, but I don't profess to know everything involved with that process other I understand it...a PP system would take longer to build 'pressure' because it requires a certain amount of flow out the valve before pressure can begin to build, thus delaying the boiling point of the system. In my case I'm building a serious off-road vehicle that will be at the lower rpm's most of the time when driving a trail but will also be at sustained highway speeds for hours to/from the trails, so a proper cooling system is paramount, and mine has the OE 19" mechanical clutch fan and mated shroud.

So I guess my quandary boils down (pun intended) to whether to go with a PP system or a FP system - pros and cons, etc.

1 - 1 of 1 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.