Hey guys...been a while since I posted anything. My 83 is starting to run hot at idle. It'll run fine when it's moving but the minute traffic backs up or if I let it run for 5 minutes while I'm in 7-11, temp gauge goes borderline overheating. Please help.
Are you running an e-fan or clutch fan for the radiator? What material is the rad (copper or aluminum, etc.)
Check if your fan is running at idle. A lot of people swap to electric fans because they simply do a better job of cooling and can be switched on and off to allow the truck to warm up quickly then stay cool once at operating temperature. Also see if there's any obstructions that could be preventing much air from getting through the radiator. At high speeds a lot of this will be less important because the shear force of the air going into the radiator can overcome a lot, but at low speeds and idle you're relying strictly on the fan's ability to pull air through.