For the scientists here...

Or anybody else who can talk to this smartly.

Does thinner/less dense air (high altitude) have an effect on cooling?

Would seem to me, regardless of temps...my truck cools better at lower altitudes. I see alot of folks saying their truck runs 184-186 max...my truck ran ~190 before I did water pump, coolant, belt, t-stat etc...runs 190 after. Maybe 186 in town, not in stop and go. Highway, freeways mountain passes, etc, I'm 190 easy...as high as 197 up the passes, 4th gear, 8-10k ft high and hot, but typically, summer at least, I'm seeing 186-197 as my temp range.

It is pushing 37's on 4.88s, which plays a part, I'm sure.

Anybody else run warmer up in high elevation?

Trying to convince myself this is fine and NOT to buy an alum race radiator.

 

At higher altitudes the air density is thinner, i.e. fewer oxygen molecules. That means the engine will run less efficiently and at higher temperatures due to the varying fuel to air mixture and less oxygen to cool. Simply put, at higher altitudes, less oxygen particles will be passing through the intake and will cause the engine to run less efficiently due to the air density compared to that at sea level.

It's a natural phenomenon and something pilots have to consider every time we fly.

 

Stolen from another forum but make some sense.


The cooling of the engine and tranny are more complicated than this but fundamentally Altitude definitely affects convection cooling capacity due to the reduced air density. This means that anything that depends on moving air to provide cooling will in general have higher temperature rises. In addition to that, the radiator fans are affected as well. For a given RPM they will move less air so its a double whammy.

 

until Ur temps hover above 200 for an extended period o time
U do not need a new radiator

ambient temps will raise the average operating temps of U engine
unless U frequent the desert / Death Valley
there again little concern

when U are in the mountains its not unusual to be gaining grade.................
essentially putting More Load on the engine..........more ' Load ' = more BTUs !
resulting in the cooling system to shed more BTUs
( 197 UP the passes is Normal !!!!)

there are hiways that run ridgelines will little change in grades
little to no load should strress the engine

no less when descending from high altitude
U should see average temps

true there is less air
yet many times its cooler

its a trade off

 

Thanks all! I'd call that a consensus...rarely found on an internet forum