2001 Honda prelude auto
I catch the temperature gauge raised a couple of times at stops on two different days. One time I started moving again and it comes back down and stay normal afterward. The second time, temperature slowly started to rise, but then I started the AC and the temperature fall back to normal afterward, and even with the AC off again. My guess is the fan got turned on. Did the temperature sensor not automatically turn on the fan initially?? I do have radiator leak, but I also add coolant
IMHO the things I'd check - 1. If the radiator's leaking, it could be corroded/clogged - not unusual after 20 years 2. The relay which turns on the fan could be acting up - cheap and easy to replace
A car can have two cooling fans, one for normal driving, and the other for the AC. When you turn on the AC, the second fan comes on to extract more heat from the system.
At a stop, you have less air flowing across the radiator, so the temp goes up, especially if the radiator is partially blocked. The normal driving fan cannot extract enough heat to maintain ideal temperature. Use an infra-red heat gun to scan different area of the radiator. If you see hot/cold spots, then replace the radiator. The use of radiator sealant products can block the cooling pipes in the radiator, which would reduce the radiator's efficiency.
The oem thermostat for my van is 195 degrees. Down here in hot as blazes Florida, I run a 160 d. one and have no problems. The engine runs cooler and so do I.
