That the radiator fan cycles on and off says a lot. it says that the engine thermostat is working, and that the water pump is moving coolant between the engine and the radiator, and that the radiator coolant temperature sensor is working.
Low coolant or an improperly bled system is the first thing to check. Another possibility is that the radiator core itself is so crudded up with minerals that coolant isn't flowing through it properly. A flush might help that.
It means your NOT flowing enough coolant to cool your car. You car will cool down once you start moving thus forcing more air though the rediator.
First check to confirm the elec fans are spinning, next Coolant needs to changed every 2 years (3 years max), so start with a flush and coolant change also change the thermostat they are cheap, then go from there.
It needs a new thermostat. THat's pretty common, those should be changed every 2 years anyways.
Most coolant is good for 5 years (not 2-3).
I had the same problem in my Honda. When the car is at idle, it is subject to more heat as opposed to when in motion. While driving, you have air flow being forced through the grille keeping the engine cooler. The fans can't replicate the wind power. What you need to do is make sure you have an adequate level of coolant. Start with the engine COLD and remove your radiator cap. Fill radiator with 50/50 coolant and also make sure your reservoir reads somewhere between the min and max line. With the cap OFF still, run the engine until you reach normal operating temperature to free the system of any air bubbles. If the level in the radiator dropped, fill it back to the top. This should fix your problem. I know you said that you fixed the leak, but monitor the level just to be sure. When you are low on coolant, the boiling point lowers which causes it to overheat. Proper level ensures proper cooling. As far as the smell, coolant does replicate a kind of fishy smell already. Hope this solves your issue.
I have a 2007 mazda 3i 2.0l automatic.
When my car idles the radiator fan comes on and the car starts to overheat.
But while im driving its fine. And also my coolant smells like fish so im guessing it needs a flush but could that be the reason its over heating?
I also had a hair line crack in the reservoir but its sealed now.
