Out of pure interest and ignorance how come? (Like to learn)

Mmm, I've heard comments like this before, and I'm no expert, but it does not sound feasible to me. Passing through the rad slower to shed more heat would have the equal and opposite reaction of passing through the engine more slowly and gaining more?!greenman43 wrote:That said, some engines need to have the coolant stay a bit longer in the rad - if it passes through too quickly, it doesn't shed enough heat ...