2004 Trailblazer cooling. (vehicle, sensor, clutch, radiator)

[oz in SC]

Mrs oz has a 2004 TB as her vehicle that she is currently driving back and forth to SC from our new home here in NC,300+ miles or so.

It ran warm(to our minds) while we had visitors staying with us(four adults in car) but not to the point of overheating.

Anyway,it now will run at just below 210 degrees(middle of gauge) while going around town but on her trip down to SC ran up to two notches above(roughly 230 degrees???) but then cooled back down to one notch above 'normal'.

Of course the temps on the trip down were in the high 90's possibly low 100's.

New fan clutch installed last year,new water pump before that.Full of fluid.
Any tricks to get it to run cooler?
Any thoughts or ideas?

Manual states not to worry until it reaches the red-260 degrees...
Thanks.

[M3 Mitch]

GM has always had a weird attitude towards hot running, like you say don't worry till it boils over...

Anyway - make sure you clean the bugs out of the radiator at least occasionally, don't believe that the antifreeze is good for "10 years or 100K miles" but change it,.

One thing you can do, is either change the antifreeze and make sure you mix it with distilled water and rather than mix it 50-50 make it 60% water, 40% antifreeze.

If the car is running hotter at high speeds the fan has nothing to do with this, it's either lack of heat capacity/flow in antifreeze/coolant, or lack of heat transfer from the coolant to the air in the radiator.

The South being the South, I would check for bugs in the radiator, flush them out with a hose when the car is cold, you don't need or want a high pressure hose like a car wash.

[oz in SC]

Originally Posted by M3 Mitch

GM has always had a weird attitude towards hot running, like you say don't worry till it boils over...

LOL....it actually stated something like that,if the vehicle doesn't cool down leave it and call for service...

Anyway - make sure you clean the bugs out of the radiator at least occasionally, don't believe that the antifreeze is good for "10 years or 100K miles" but change it,.
One thing you can do, is either change the antifreeze and make sure you mix it with distilled water and rather than mix it 50-50 make it 60% water, 40% antifreeze.

Yeah,I cleaned the radiator,might try changing the coolant.

If the car is running hotter at high speeds the fan has nothing to do with this, it's either lack of heat capacity/flow in antifreeze/coolant, or lack of heat transfer from the coolant to the air in the radiator.

This is probably the most problematic vehicle we have had for cooling,of course GM was trying to be all whizz bang and put an electronically controlled clutch on the cooling fan,I believe it has been redesigned three or four times now due to issues(none that would have warranted a recall of course...)
Also there are I think four or so sensors that control the cooling...

The South being the South, I would check for bugs in the radiator, flush them out with a hose when the car is cold, you don't need or want a high pressure hose like a car wash.

I will call my wife and tell her to try that,we also live down a few miles of dirt road so that probably doesn't help either.

Thanks.