'02 Pontiac Grand Am GT Engine Temp Rise when Idling

After driving with the engine warmed up to normal temp (around 200),
when i get stuck in traffic or at stop lights my engine temp slowly
inches up to the 230-250+ range. I've had a new thermostat installed
and had the coolant flushed, but it still does it. The only thing that
seems to lower the temp (while stuck in traffic or idling) is turning
on the heat full blast.

Does anyone have any ideas what could cause this? Probably an
expensive fix....

<paleface23 DeleteThis @gmail.com> wrote in message
news:1163621509.943389.18530@k70g2000cwa.googlegroups.com...
>
> After driving with the engine warmed up to normal temp (around 200),
> when i get stuck in traffic or at stop lights my engine temp slowly
> inches up to the 230-250+ range. I've had a new thermostat installed
> and had the coolant flushed, but it still does it. The only thing that
> seems to lower the temp (while stuck in traffic or idling) is turning
> on the heat full blast.
>
> Does anyone have any ideas what could cause this? Probably an
> expensive fix....
>

Well, something isn't letting the radiator blow off the heat.

The heater bypasses the thermostat, so the fact that you had a new
one installed should at least change things.

Is the radiator getting warm? Is it getting hot? It should be getting
hotter than hell when the thermostat opens. If it isn't then either the
radiator isn't getting the hot water due to a thermostat (did you put
in the right one? a wrong one can warp and jam ), a clogged
hose, or or a clogged radiator. If worse comes to worse, you can
pull the hoses and make sure they didn't 'delaminate' on the inside
and clog. Or pull the radiator and make sure you can 'flow' water
through it with a garden hose.

If the radiator gets hot, are your fans turning on? If not, then figure
out why.

It everything 'appears' to be working, pull the radiator and examine
the cooling fins. I had a Dodge where the fins corroded away and
THREE shops couldn't find the problem. Then I went to this little
"Bills Radiator" backyard shop. He took one look and told me it
was the radiator. Pulled it out and all the little 'foils' between the
cooling tubes were corroded so that they were nothing but paint
shells. Amazing the thing didn't leak, but he told me it was something
to do with the 'artificial salt' they used for a couple of seasons here
in Mass.

My Dodge would run just fine on the highway. But idle in traffic
and the temp would start climbing. Fans just can't pull as much air
through as movement.