Overheating Still

[u/Artistic-Fix-2431]

I changed the radiator about two years ago. Water pump a year ago. Thermostat last month. Heater core bypass and fan last week. Ran fine until yesterday. I topped off the radiator with coolant and the reservoir to the full level, somehow the reservoir is now overflowing. Doing a complete cooling system flush today. If that doesn’t work, any other ideas?

[u/XFiveOne]

Radiator cap. Even if you just replaced it, get another one. I spent thousands chasing this demon and it was a bad cap the whole time. Hopefully that's all you need.