1997 Pontiac Trans Port temp sky rockets in-town traffic fine while driving water pump or radiator?

Answer 1

Probably the electric cooling fan. Check to see that the fan turns on when the engine is hot. If not, find out why. DARKSEID007

My Advice: May also couple of other problems, such as radiator may be starting to clog up with mineral deposits from hard water and causing it not to correctly cool when driving at lower speeds. Check for white looking deposits near the openings of the flues inside of the radiator, (they are on the wall going through the center of the radiator) if need be suck out some of the water to get a good look at it with a flashlight. If the flues are starting to show signs of minerals deposits or such, remove the radiator or have a mechanic remove it and have it rodded and flushed by the local radiator shop. Could also be that you may be using the red Dex-Cool coolant that is supoose to be compatible with the green coolant and there is an issue with the red coolant that they fixed with the introduction of yellow Dex-Cool. Now currently on the market. Dex-Cool dissipates the heat, but may be holding more heat than what it is pushing out of the radiator. (Even check the radiator for clogged lines through the aluminum center of the radiator and use a pressure washer or other high pressure device. (Careful not to get too close to the center or damage could occur) Honestly, I would flush the radiator or have it flush by a mechanic and have the green coolant replaced back in it. Too many issues with the Dex-Cool turning to sludge in the radiator, This is a common problem with the 3.4-3.8 liter GM motors, Google it if need be. And last answer try the above submitted answer that was post at the first of the article. Hope this helps.