I need help in trouble shooting a heating problem ? I purchase a 1996 Honda Accord Lx and I notice the first month I had the car it was in cold weather so the temperature gauge stayed pretty much an inch below the half line. Now since , its getting hot the car goes sometime almost to the hot but it never over heats. I Purchase An OBD2 code reader for this vehicle for $98.00 at walmart. The Code Diagnostic read PO 301, PO 303, PO 304,PO 302, PO 1300 which says misfire detected. I recently changed three spark plugs in stead of four the forth one appears to be stripped or it just seems impossible to take out . But even with these things changed the car run smooth, no misfire. We also changed the thermostat 4 days ago and still the temperature gauge goes up. Oh! Another thing we also tested the temperature sensor and it still marks the gauge up and down like it wants to go on hot. The car has a new THERMOSTAT,THE SENSOR is fine , what else could be causing this problems? HELP!!

Thanks pjo3

You may need to have your radiator rodded or replaced. Corrosion and mineral buildup can block the passages. Only use a 50/50 mixture of antifreeze and distilled water.

Also there could be a problem with your water pump. You should be very careful this car has a aluminum block that can be destroyed, by overheating. My advice, try cleaning as tx said if this doesn't work consult a professional..

Did you bleed the system? If not you could be driving around with a nice air pocket. Get the spark plug out and repair threads.Note: be sure when you heli-coil threads that valves are CLOSED! If not, you will bend one. Misfire should not be hard to trace. Spray fine mist of tap water over wires and see if are arcing. Easier to see at night. If so, Replace with only Factory Honda parts. DO NOT go to Parts America or any other crappy aftermarket store. You will only be spending that much money next year. Honda wires have tendency to last 10 years or more.