Car Runs Hot after Coolant Change
About a year ago, I decided to change the coolant in my grand prix gxp. It
was probably the original coolant and had about 100,000 miles on it, so it
needed to be changed. The process of draining the majority of it and
installing a new thermostat (186ºF) was smooth enough.
Ever since that day, if it were particularly warm outside, the engine would run
quite a bit warmer than it used to. The temperature gauge on my dash would
have its needle right down the middle at all times, even in 100ºF weather.
But now it will sometimes get uncomfortably hot, bad enough that I blast the
heat in the cabin to cool it down (see picture, it sometimes is hotter than
that).
What I want to know is why is the engine running hotter now? I even used
one of those spill proof funnels to ensure I got all the air out of the cooling
system. Could the thermostat be damaged? Did I miss something specific
on this 5.3L V8? Or it is particularly difficult to get all of the air out of this
engine? If so, is there a valve to bleed the air out? I honestly don't know, the
only difference from before to after is the new coolant and thermostat, and
nothing else.
