Two weeks ago my H3 06 engine light came on and Onstar reported that it was the cooling system. GM dealer advised me not to drive it back to them for repair, so I had a local auto shop look at it. They said I needed a new thermostat. First I must add that my car had only heated up to 3/4 line a couple of times and only on very hot days with on ac on. So I get the new thermostat and it immediately went passed mid range and when going up hills 3/4. Shop said no problem it's fine. Not trusting them, I take it in to GM dealer last week and now have another repair. They say it needs a new fan motor. Great! Two days later I go in to pick him up, and the service manager said all is fixed BUT your truck will run a little different. Well, long story short, on the way home I had way less power on the hills and it is STILL heating up to 3/4. He said not to worry until the on board computer tells me it's over heating. My truck never ran this hot before. Am a women but not stupid about cars having run a car care center years back. Can some please explain to me what might be the problem now, or should I just stop looking at the gauge every 5 sec.? Thanks for any help.

 

They took all of your money for nothing. Your temp gauge going up to the 3/4 mark is not over heating. A local shop is usually just going to start with the thermostat, but with the h3 there are many things that it could be. So in this case I would suggest taking it to a G.M. dealer that has hummer techs. a regular shop could end up replacing many things and cost you tons of money before they ever find the problem, and they still might not get it fixed.

Has the antifreeze been pouring out of the radiator from the cap? or smoking or anything? With just the temp gauge going up to 3/4 it is not overheating. THat's right where ours is and has been for the 4 years we have owned it. To actually know what your temperature is you need to take a reading with a thermometer. The gauge doesn't tell you what the temp is. I would be complaining to that shop because they ripped you off. They were in over their heads or they just don't have the capabilities to do all the tests necessary to diagnose what the problem actually is, where in that case they should have told you instead of just randomly replacing a part that was working perfectly fine If you are overheating your gauge will go all the way up into the red.

 

I recently charted the temp from startup. the temp was 90 at the first needle movement off the bottom. the highest temp I hit was 200 with a blanket over the grill and the engine off in heat soak. running it was 195 max. I never got up to 1/2.

so the first half of the gage,fairly linear, covered appx 100 degrees.
if we assume continued linearity the top would be 300 deg and 3/4 appx 250.
I cant get up to 1/2 in any way so someone who sees 3/4 should get a reading,knowing that the gages may not all be the same. but my 2 h3 both read the same, never getting up to 1/2,even in stop/go in very hot weather.

I don't know what the danger point or "blow"
point is. but 250 sounds pretty hot to me.
unpressurized water boils at 212.
someone add a 3/4 temp huh?

 

There are many of us reading at between 1/2 and 3/4, and there are many that read just below half while driving. That gauge does not tell temp. Like I said you have to get an actual temperature reading so you know what the temp means. That gauge means nothing unless it goes all the way up. It's just an idiot gauge.

 

If some loser at the GM dealer told you that you needed a new fan motor that person is wrong. The H3 doesn't have a fan motor. The radiator cooling fan is driven by a belt. If they charged you for that item they are crooks.

 

Thanks for all your help. The part that GM installed last week was called a fan clutch. Do any of you think that the first shop might have put in a bad thermostat? My old one seemed to work better and truck didn't run this hot. What else could possible be wrong with my Hummer now? Thanks again for your help. I get sick when anything is wrong with my baby.

 

What is wrong with your hummer? The needle on the temp gauge is going up the 3/4? If so then there is no problem. What makes you think it is overheating?

 

The reason I think something is wrong is because with the old thermostat it ran cooler and before the fan clutch motor was replaced I had more power on the hills on the freeway. I live in northern California in the foothills and the temp can get too 105 outside. The last thing I want to do is watch my gauge the whole time I'm driving.

 

You need to talk to someone who can address your concerns. You wrote "the service manager said all is fixed BUT your truck will run a little different" That's concerning. I would have asked Why will it run different? And you said "it had way less power on the hills". I would go back to the GM shop and talk to their senior mechanic.

 

Thanks, that was great advise. I should have asked the service manager at GM. I'm just to trusting, but that is going to stop with any future repairs.