Temperature

[Clark]

Hi
New member here I'm trying to understand my 07 H3. I had my cooling system flushed because to me the Dex-cool was a little dirty. And I changed my thermostat. I'm wondering what is the proper operating temp? when hot my gauge is halfway up, but when I'm at a stand still at idle she goes up to almost 3/4. Is this ok? I appreciate this lesson. Thank you.

 

[3Hummers]

We have the V8 and that is normal for us. Not sure if the 3.7 is any different or not.

 

[Clark]

lol. I'm starting to think that maybe changing the water pump might help. I wonder? thanks

 

[K0PIR]

Use something like a scangauge for an accurate reading.

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[CaddyStrophic]

Owned a 3.5 and now a 5.3, both operate/d right at the 1/2 mark on the temperature gauge. Never really had them stray too far from that.

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[3Hummers]

3/4 is normal for us with the AC on.

 

[Clark]

Really guys. when sitting at idle she climbs up to almost 3/4 then I start praying about not overheating. But then when I drive off she drops back down to 1/2. I think it's scary.

 

[JPaul]

Could be the water pump or the fan clutch I would imagine.

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[3Hummers]

Been driving our 08 like that for 8 years and 125K miles with no issues. Once again ours is the 5.3. I would try a Scan Guage if you have access to one. They aren't expensive and will give you accurate temp readings.

 

[Clark]

Thanks guy's I will have my clutch fan checked and I'll try to get ahold of a scan guage. My fingers are crossed. lol

 

[ENASNI]

Mine rests just above the half way mark. It gets up around 3/4 when stopped at lights. I'm going to change my pump, fan clutch and thermostat to see what that does. Still thinking about going with a 160 thermostat.

 

[USMC_TOP]

If it was fine before you did the thermostat change I would change that back to the 160 that came In the truck before wasting money. I believe there are past posts in here somewhere about this issue. Your not the first.

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[4speedfunk]

Possible air in the system. I say this for two reasons: One because the temp mysteriously drops when you accelerate. The sensor may be reading "steam" vapor at idle....then when you take off, a slug of liquid floods the sensor and you get the real reading. And two, the only thing you did was flush and fill.
Purge the system with a vacuum pump and see if that fixes it.

 

[rascole]

Let it idle with the radiator cap off for a while. The lack of a pressurized system will allow the trapped air to move out.

 

[alrock]

I would second to vote for fan clutch if it going that high at idle. But 3 Hummers is also right that three-quarters can be normal at least when its warm outside and under load

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[alrock]

I replaced my fan clutch recently for the same reason

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[Clark]

Ok so would you guys say it's normal? I'm going to change the clutch anyway, I'm wondering is it me? lol I'll keep you posted. thanks so much.

 

[Best4x4]

On a 3.5L or 3.7L you've got to remember if you replace the thermostat vs your OEM unit that you will not longer be running a 180F unit. GM changed the temp range from 180F to 190F. They did this due to the P0128 fault and for better emissions. With that being said your temp gauge will no longer sit below half on the gauge. It will sit right at half or above now with the 190F thermostat. I ran into this issue when I bought my 07 H3 and I replaced the radiator, waterpump, thermostat, and fan clutch. With a 190F thermostat (you'll never find a 180F unless you come across a NOS crate full of em), your temp range will be 205-215F. I had a scangauge II and monitored my 07 H3's temps and after the newer thermostat that was the range it ran for 1.5 years. Before that it was in the 195-210F range.

So your temps with a new thermostat are perfectly normal.

 

[Clark]

Thank you lesson learned. I even changed the hoses when I flushed the cooling system and the thermostat. How do you feel about water wetter cooling additive?

 

[Best4x4]

I've used the Royal Purple version of water wetter, and it made a small difference. My brother used it back in the day on one of his Range Rover Classic's and he said it helped some.

 

[USMC_TOP]

If it was fine before you did the thermostat change I would change that back to the 160 that came In the truck before wasting money. I believe there are past posts in here somewhere about this issue. Your not the first.

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I ment 180 sorry

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[USMC_TOP]

Too funny. My thermastat caused a cel the other day. My 3 would never get pass 1/4 in the winter and never pass 1/2 in the summer. After changing my thermastat (54 bucks from gm) WTF???? I am at the 1/2 now with lots of heat. My Stat was stuck wide open. Curious now on what it's gonna do this summer.

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[Best4x4]

You'll honestly probably run 10F warmer on a 3.5L/3.7L. Since the 180's turned into 190's for emission reasons on the I5.

I had to look and look for a darn true 180F thermostat for the Alpha as all local auto shops were basically selling 187F which is close enough to being called a 190F. I had to cross reference a Camaro/Corvette/1500 pickup vs looking up the H3 which just showed "Not Compatible" which is complete BS..

 

[SuperBuickGuy]

It's funny, I had no idea how it worked until "How It's Made" did a blurb on thermostat construction... here it is
[video=youtube;FzMpsJPa4o0]https://www.youtube.com/watch?v=FzMpsJPa4o0[/video]

 

[JPaul]

not much has changed in thermostat design. Got to love when a century goes by and your still using almost the exact same technology. Like pencils...

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