Hey Scotty, I have a 2011 Honda accord LE. 127,000 miles. Heater blows cold at idle even after letting it run for 15 minutes. BUT, when the car is driving around it will literally blow so hot you have to drive with the window down. Even at half way on the hot/cold selector. Coolant level is snuff in reservoir and when cap is off. ALSO… today the dash temp gauge got close to red line while idling after driving most of morning. Had to shut the car off and let cool. But when driving it stayed midway and was fine. What in the world would cause these things? It’s been happening over last week or so. Thank you
Your water pump is toast
Stuck thermostat, bad radiator cap, water pump intermittent failing, heater core blockage, etc. What do you mean by "coolant level is snuff" and what does the cap off have anything to do with anything?
Coolant level in reservoir is at proper level and when I take the radiator cap off I can see the coolant. Thanks for the advice!