HI!
I have 2007 hummer h3 3.7L auto trans. In summer we have 112F temperature here. My H3 heating gauge always stay at 3/4, some times it do go little up. I have watch dog monitor installed. 3/4 on temp gauge is 221F. Some time it do go around 230F. Do all H3 heat this much? I had changed the Fan Clutch, washed up radiator and added new Ac Delco Yellow Coolant, but heat temp stays the same. Is there anything else i can do to make it run cooler.

 

Normal for h3's. They appear to run hot, but they dont. It's just the nature of these trucks.

 

One question, Does it do it all the time when the vehicle warms up, or does it only happen whilst sitting or going slow through a trail?
My H3's temp use to be about mid way on the gauge unless I sit for a while after running for a bit, or like 3/4 when I'm mudding and going slow. I think my thermostat just went out beacuse I got the error code P0228; which means the thermostats bad. Now when my car finally warms up its always at 1/4 which is unheard, at least to me. (I live in FL)
If your ever afraid that your hummer might overheat just turn the air to panel and turn the heat all the way up, although it might be hot in your truck it turns on an extra fan and pulls more air through your radiator (since your asking for heat it takes it from your radiator and puts it in your a/c system) thus cooling it down.

 

when you have the ac on, it runs at 3/4, when it is turned off, it goes down to just under 1/2. it is normal. i usually dont run my ac because i roll my windows down bc i live on the ocean and get the cool breeze from it so... but it is normal

 

I checked. with AC it goes 3/4, without AC it goes to 1/2. its very hot and humid here so i have to run AC. I just have to live with over heating then. I am thinking to install Flex A Lite electric fan or go with bigger fan blade, that might keep it cool.

 

Just because it looks high on the temp gauge doesnt mean it's actually running high.

 

Yeah, thats true for me as well.