2002 yukon Z71 thermostat question

[s1ic3r]

hello all, and thanks for a most excellent and informative forum,

Gawd i'm dumb, its a 2002 tahoe z71 5.3 l vortec with 150,000, sorry for the confusion I seem to mix up the tahoe/yukon since its new to me.
I recently developed a slow coolant leak and could see evidence of leaking from the bottom bolt of the thermostat, so I ordered an ac delco tstat that was matched to the ac delco water pump that was appropriate for a 2002 yukon Z71 with front and rear heat/ac. the water pump I also ordered just in case the leak wasn't limited to the tstat.
it turns out that I replaced the tstat only and sent the pump back.
As it turns out prior the the tstat swap the coolant temp ran pretty much between 185 to 190 and the one that came out was marked 187 degrees. The one that went in had no markings. Everything seemed to go fine and the amount of coolant that came out pretty much matched the amount that went back in, my issue is the coolant temps now run pretty steadily between 196 and 198 so obviously (to me) the tstat that replaced the old one wasn't the same.
Welp, not being by any means a mechanic im not sure if I should replace the new one with a confirmed 187 degree tstat or if it ok to run a little bit hotter, sadly google is not my friend and all i've been able to find are articles having to do with the finer points of running the engine hotter or cooler. I also can't seem to locate info on what exactly is the temp the engine should be running at. I need help!

and thanks

 

[Marky Dissod]

I need help!

No you don't - unless for whatever reason, you are unable to burp the cooling system yourself.
Once you burp all the excess air out of the cooling system, it'll cool off.

 

[s1ic3r]

I thought I had the system burped, but i'll go another round with it, I found a great how to on the forum here so i'll try that again in the am.
thanks

 

[Fless]

Your thermostat temp is an opening temp, and the engine will run hotter than that, depending on the efficiency of the cooling system. 200°-210° F is normal.

 

[Eldiablo]

I always drill an 1/8 inch hole in all the t stats i install. It does away with all those problems. Also if the t stat shuld stick closed it insures you wont fry a motor.

 

[Marky Dissod]

As it turns out, prior the the tstat swap the coolant temp ran pretty much between 185F to 190F,
and the one that came out was marked 187F.
The one that went in had no markings.
Everything seemed to go fine, and the amount of coolant that came out,
pretty much matched the amount that went back in.
My issue is the coolant temps now run pretty steadily between 196F and 198F,
so obviously (to me) the tstat that replaced the old one wasn't the same.
Not being by any means a mechanic, i'm not sure if I should replace the new one with a confirmed 187F tstat,
or if it is ok to run a little bit hotter?

You never once mentioned when you last replaced the radiator.
I'd be pleasantly surprised if yours has lasted longer than a score / two decades! ...
but in all that time, I guarantee it is running hotter than it did in its childhood.
When the day comes for you to replace your radiator, it may help to know that, besides the two main coolant hoses,
there is a 3rd coolant path, roughly the size of ... a child's finger? A moderately sized handgun round's spent shell??
Make fun of me for not knowing the exact size - I deserve it - point is,
1. if the system runs too hot for your taste, that hole is too small,
2. if the system runs too cool for your taste, that hole is too big, and
3. finding a way to personally calibrate the size of that hole is quite empowering.

I feel 'great' about a cooling system that stays under 212F.
I see no reason to worry about a cooling system that stays under 221F (or 212F if the pressure cap is going 'lame').
I start keeping an eye on a cooling system once past 221F ...
I get nervous once a cooling system approaches 230F - I better be pulled over before 239F at any cost.
Everyone forgets that where the coolant temp is measured, is NOT the hottest spot in the cooling system.