sorry u i am new hummer h3 owner and was winder what is a normal in a hot summer day? is almost 3/4 considered normal

 

Welcome to HF.

YES, 3/4 is NORMAL. Search that out. The dash Temp Gauge is like an idiot light with a needle. You need to use a scanner to see the actual temp to know what is going on.

Example: my H3 might show 1/2 on the dash gauge and the actual temp is 195F, your H3 might also show 1/2 on the gauge, but actually be at 200F. Another H3 might show 3/4 on the dash gauge and the actual temp is 205F. All pretty darn normal depending upon altitude, humidity, ambient heat and load.

 

If the engine is actually running this hot at 3/4 this can be a restriction in the radiator or engine causing a low flow of the cooling system which will then cause the engine to heat up like this when warmed up outside.You would want to have a complete coolant flush performed and the radiator checked to see if it needs to be replaced ( if it will not flush out and flow correctly).
Normally half is 195-205, then after that midway between 1/2 and 3/4 is 210-220 and 3/4 and above 220-237

 

I'm living in hot place and I'm owing h3 for more than 12 years.
every summer my catlr temperature reached to 3/4 especially if I'm stuck in traffic and the car is barely moving but i highways it never reached that high

 

Driving on city streets, stop-n-go traffic on HOT days 90°F+, I see this on my gauge:

 

Dang. Mine hardly ever gets past 1/3.

 

I’m with Hummerz, I live in NM at 90-100F outside, 5000-7000 ft above sea level, gauge is always one needle width below 1\2.

I did add water wetter to my radiator fluid when I bought it though.