For example my stock '85 AMC idles at 12* BTC, 650 rpm but when a temperature control switch (HD-CTO) sees the coolant is 220 F its lets manifold vavuum to the distributor advance.
I have always been a believer in manifold vacuum advance so an engine can idle and cruise above initial timing, which is typically a small number like 5 to 10 degress. This just confirms more is better.
Although a few degrees of timing should NOT change an engine from overheating to normal. If it does, it was on the edge in the 1st place.
As for GTXOsnfri, heat during idle generally is fan. Do you feel alot of heat being blown through the radiator by the fan?
