Howdy all,


I took on the great task of replacing my thermostat on my 2007 H3. Everything was as stated here and that top bolt just sucks to get to!


Question for those who have done it - I find that my temperature on the dashboard is running around half between Low and High. I don't recall this on the previous thermostat. I did do a search and saw some comments mentioning the same.


I guess I am hoping to hear from someone that yes, this is correct or there is something else to check!

 

ive had 2 h3 3.7's. both read just under 1/2 scale when hot.
after rad change slightly lower,??? dont know why, have new t stat but putting off what sounds like a pia job!!
also tiny leak at water pump i think,have pump too, same excuse!!

 

The dash temp gauge is not a precision instrument, one dash cluster might show 1/2, another swapped to the same truck might show 3/4. Suffice it to say, the intent of the dash gauge is like an idiot light with a needle, if the needle goes to Red, shut it off, if it is somewhere around 1/2 to 3/4 then all is good (1/2 - 3/4 is NORMAL).

If you want to see what the real temp is, get a basic OBDII scan tool, like a scan gauge or smart phone adapter like the BAFX Products 34t5 Bluetooth OBDII reader.

The replacement T Stats are 5 degrees F warmer than the original issues from years back. My original ran about 188F, the new one I put in shows 193F, gauge on the dash is the same as always, about a tad over 1/2. It will get warmer with hot humid weather, and warmer yet when you turn on the AC in that kind of weather.

 

And yet you don't say what it read before the installation?

As Doc said, your temp is "normal"; just keep it out of the red.

 

I just changed my thermostat and my temps raised as well. Used to run around 176 degrees with the needle at 1/4 position. Now it's just above the halfway mark but haven't checked the temps. Could be placebo but engine seems to run much smoother ..

 

Maybe I should add, that when the orig T Stat went bad, the temps hardly ever got over 174 (after a bunch of driving) and the dash gauge was well under half when it kept throwing the P0128 CEL.

 

All,


Thanks for your comments. Sounds like I am running around where others are seeing it after a thermostat change. Doc Olds, thanks for the input on how to identify the true temp, I will try that.

 

Welcome to the exclusive "Changed my T Stat Club".... or maybe that is elusive, or reclusive????

The top bolt is not a big deal to get out or torque back in, but getting it started with the new one in place sure was fun.

 

Here's another gauge needle observation, but mine is backed up with a scan tool. I normally sit at about 1/2 way on the gauge. A couple of days ago, I plugged my scan tool in to reset some codes afte doing some work. I noticed that my normal operating temp is about 206. Today. I noticed the needle climbing. When it got up to about 3/4, I plugged the tool in. It was at 217 and climbed as high as 220. At that point, I turned off the a/c and turned on the heat. Dropped down to about 208 quickly.

My radiator is about two years old, as is my thermostat. External trans cooler. Water pump was installed during this last winter. All fluid was checked and replaced. I'm thinking I've either got an air pocket somewhere, although this might be unlikely, or my t-stat has gone bad. Before I tear into it, I was going to ask for opinions. What do y'all think?

 

3/4 on the gauge, 217-220F, up to 225 when humid, when the AC is on = all normal for the H3. GM wants that truck at 195-220 all the time for emissions purposes.

Boil over is about 265+ for an H3 with a proper functioning 15PSI radiator cap and 50/50 coolant to water mix. You got lots of room before that happens.

You need not turn off the AC (we won't be using any up here in MI for a couple months ) because the PCM will do it for you if it gets close to too hot.

While wheeling in warm (upper 60s) conditions, my scan gauge will show 219-222 under load climbing hills etc and kick on my Efan for a while, but that is not anywhere near an overheat.