My Dodge Neon 97 just started overheating but only when idle. It doesn't matter if the air is on or not. It pushes heat out when i turn the fans on high. However if i get going it cools off and is fine. It will only overheat if i leave it running parked for more than 5 minutes. During the winter this doesn't happen at all but the heat is running all the time.

 

I would check the engine fan, make sure they are coming on

 

My 95 sohc did the exact same thing, slow spped or sitting and it would heat up or overheat, on the highway it would run cooler, almost normal, does your heat slightly rise when going up a long hill? mine did and it was my rad that was shot... my rad looked good, flushed out properly, had a new rad cap and a new rad fan installed and a new thermostat and none of it helped... the rad was shot, i got a new rad for 160 canadian at whites radatior in fredericton nb i got the bigger rad and new hoses for cheaper than the small rad...

So i would tell you to remove the fan and take a really good look at your rad, its fins may be pluggged with dirt, if they are greenish it is probibly going bad so it should be time to replace it. Hope that helps you out.

 

YeaH IM GOING THROUGH THE SAME THING i FLUSHED MY RAD, CHANGED THERMOSTAT, cHANGED THE COOLANT TEMP SENSOR, DISCONNECTED ECU, IT HAS BEEN A PAIN IN MY ****!!!! AND I WILL TRY THE RADIATOR BUT IF THAT DOESNT WORK IM GOIN TO CHUCK A BOMB AT IT. lol NO NOT REALLY

 

yeah if it happens while just sitting still, first thing i would check is to be sure the fans are even comin on. i know that the fan relay is a common problem, starting with i think the '96s.. so thats the first thing i would look at really.

if the fans are indeed coming on as they should, then the problem definately lies within the cooling system itself. possibly a bad thermostat and/or radiator cap.

 

Oh yeah my fan comes on, however, not until it is in the redzone and chiming. The only way I even it out is turn the heat to RED and open a vent.

 

hrm. your fans are coming on way too late then. i know mine will come on well before it ever gets to the red area and chimes.

 

Right it should.........however the coolant temp sens is brand spankin new. cant figure out why it would kick on so late??????????

 

Overheating is most often caused by air in the coolant sytem. Even says so in the FSM.

With the engine cool, take off the rad cap, start the car, and let it heat up until the thermostat opens and you have flow. Chances are, level will drop, so have fresh coolant ready to put in. This may take several tries since the thermostat closes as soon as you dump cold coolant next to it... Make sure the overflow tank is at the proper level, then shut off the engine, install the rad cap (preferably a new one), restart the car, and see if it's better.

Other causes would be a failing water pump, plugged radiator, crimped hoses, rad fan issues, or faulty thermostat (or a combination of any of those...). Air most often gets in through the rad cap as it ages. But small leaks at hose connections, the radiator itself, or occasionally the heater core will allow coolant out as well as air back in as the system cools and the coolant contracts. If the overflow tank is below minimum, air could be getting in there as well.

Best of luck!