The Stovebolt Site Forums The Shop Area Engine Shop Good thermostats?

lilrobo: if it's only at lights while idling and not going down the road, it's probably the fan. When you're going 50MPH the airflow through the radiator is sufficient to cool it with no fan at all 99% of the time. When you sit at a light, though, your fan isn't pulling enough air to keep it cool. You might notice if you bring the engine up to say, 1,500RPM, the temp drops due to the fan pulling more air. Try to get the fan up close to the rad and run a shroud, you shouldn't have any trouble then.

My problem is temp spike on initial warm-up. (And running hot at speed, to some degree.)