Can anyone tell me if these two problems are related? Got a misfire and the van is a little jerky while driving. The radiator first ran dry about 8 months ago. Refilled it, have flushed the radiator two months ago and then last week, it ran dry again. Is it reasonable to suspect that I have a bad valve or cylinder causing the engine to overheat and therefore the rad fluid is running out? No fluid ends up in the reserve and the radiator is definitely not leaking.