< firstname.lastname@example.org> wrote in message
> >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.
Have the modules scanned for any fault codes
Try testing the pressure cap. this will cause a boil-over which will cause an
overheat. If you don't have the tool, try this link. I get my tools from
or it may be cheaper to get it tested by a shop,
good luck, repost with results.