I have a 99 Dodge Neon which recently started exhibiting some bizarre
behavior. Originally I had to replace the radiator due to corrosion.
So I got a new aftermarket radiator, new hoses, thermostat, replaced
everything, filled her up with 50/50, ran the car until all the
bubbles dissapeared, topped it off a little bit more. Car ran fine for
Now the bizzare stuff. Like clockwork the car will intermittently
overheat after running (under load or just idling). 2 minutes or so
after first starting the car and just normal driving the seat belt
alarm will come on for about 10 seconds then go off, 3 or 4 minutes
into driving the radio will "blank out" for about 4 to 6 seconds then
come back on, interior and exterior lights will periodically dim, and
most importantly - 10 minutes or so after having reached operating
temperature (about 1/3 up on temp gauge) the car will overheat.
This is not a runaway overheat condition. The temperature gauge will
suddenly max out, the audible alarm will sound then after a few
seconds (10 to 20) it will back down again. Then it will
intermittently repeat all of the above from the seat belt alarm down
to the temp maxing out again. It will continue doing this until I turn
off the engine. It will repeat everything the next day after having
sit overnight or just a few hours.
When the temp maxes out I turn on the heat inside the car to help it
shed some heat. It helps back down the temp gauge and it will
fluctuate around middle then max out again for a few seconds
I have checked the fan fuse (fuse ok). The fans work though I believe
they may come on too late at times. I have replaced the temperature
sensor/sender in the head. All coolant levels are normal. The
reservoir is always half full. There is no coolant in the oil so that
rules out a cracked head or head gasket. Is the computer bad? Or could
it be a relay somewhere that's bad? I've spent hundreds on this car
and no mechanic has able to properly diagnose this problem so far.
Anybody have any ideas?? Thanks in advance.