[Formulajones]

Like QuickSilver explained, it's really determined by how efficient the cooling system is. The thermostat just sets the minimum temp the engine will run, but you need to have a capable cooling system to see it.

If you run a 160 stat and the cooling system is subpar, then it will still heat up to a point where the cooling system can eventually maintain it, and that can be virtually any temp above the thermostat rating.

If you have a really good cooling system it'll maintain any low temp thermostat you put in there.


Removing the thermostat doesn't necessarily mean the engine will run cold, if the cooling system isn't that great to begin with.

[ZeGermanHam]

Originally Posted by Formulajones

IIf you have a really good cooling system it'll maintain any low temp thermostat you put in there.

I've just never seen a cooling system that is "good" enough to allow a Pontiac V8 to achieve an operating temp of 160F or lower with normal summertime outside temps.

Are there actually people here who have been able to achieve a 160F operating temp in summer driving?

[Formulajones]

Yep, we have a few cars that do it.

Our usual summer temps are well over 100 degrees here. So when it's that hot the cars generally run around 170-175 degrees.

Now that it's cooled off to the 80's the cars will run right at 163-165 degrees, which is where the thermostat is fully open.

Last weekend we drove up and over the mountain and the ambient temps were in the low 70's last Saturday. Mine was running 158 degrees right where the thermostat just cracks open, so it never gets any colder than that with the 160 stat. At times where I cruised with the rpm up for a bit I could get it to 163 degrees, but would drop right back down to 158-159 at low rpm and idle.

Dads car was doing virtually the same thing following behind me.