I totally concur! I had problems with mine too. Sitting at a light or stuck in traffic... watch the numbers climb. Check the radiator holding box... it probably stuffed with leaves or you have mulch in the cooling fins. It only takes about an hour to 90 minutes to pull the radiator in your driveway. The longest part is draining it... Disconnect the battery, pull the bolts from the upper radiator box, the fan and the a/c condensor... I think that's it. The top comes off. Oh yeah, pull the tranny lines and the radiator hoses. NOW, you can pull the radiator out. Blast the cooling vanes with a garden hose sprayer (close off the tranny connections first!) and watch the muck come out of the fins. I had a cracked plastic holding tank on the end of mine. I didn't realize that it was the culprit for the leak; I assumed it was a cooling vane leaking, so I added radiator stop-leak. Bad move. The passages are too small and the stop-leak pellets ended up causing more problems. I learned this from the radiator shop. I walked into the bay holding only the radiator and this 60-something year old guy by the tank said, "Whatcha got there? A Corvette radiator?" I smiled and said, "I'm in the right place, huh?" He said to NEVER use stop-leak on the Corvette radiators. I picked up the stop-leak tip from a Corvette specialty magazine that shall go un-named. The repair guy said the passages were too small and the pellets will lead to worse problems, like my cracked tank. He replaced it, pressure tested it and even gave it a shiny new silver paint job for $85. He had it done the next day... I guess I had to wait for the paint to dry. It hasn't gone over 200 degrees since then. I took the car back to the same shop for a fuel injector cleaning and when they said they bypass the fuelpump and hook up a bottle to the fuel rail and let it idle for 20 minutes, I winced. I told them I wanted to be there to make sure it didn't overheat. I out one of those little floor-drying fans in front of the radiator and directed the air into the opening... never got about 184 degrees for the entire 20 minutes it sat there, just idling.
Bottom line, check your radiator box and make sure it isn't packed with debris. Pull the radiator and blast it with water or take it in for a tuneup. Don't forget to "burp" the cooling system when you reinstall the radiator and fill it with antifreeze. (Fill it until full; start the engine and when the thermostat opens, top it off and cap it. It helps to have someone run up the idle to about 2,000 rpms AFTER the thermostat opens and you are capping it. It'll suck the level down a little to prevent overflow)
