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2002 chevy trailblazer_lt_ext
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Discussion Starter · #1 ·
When I stop the engine after driving for a long time , i hear the voices of boiling water in the engine and radiator, and i see that the Dex-cool pack if full and the water will reatch the cap .
the overheating just in the traffic and town driving with ac on
so in this hot weather, and with overheating problem in the engine ,i will remove thermostat forever
Is there a problem after removing the thermostat?
 

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2009 chevy
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Removing the thermostat is only adding to your problems.

This engine (like all modern engines) is designed to operate at a certain temperature.

Find the original problem and fix it, then replace the thermostat.
 

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2002 chevy trailblazer_ls
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Make sure that the fan is operating all the time with the a/c on. If things have not changed since I was in service, the fan should be on continuously in traffic with the a/c running. If you can get some one with a Tech2 to run through the test sequences, you should be able to tell easily if the fan is working properly. Also, when was the last time the cooling system was serviced? How many miles on the vehicle? There are too many things that can be causing the problem, you need to have some one diagnose.
 

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2004 gmc
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What you propose is similar to having a fever, and cutting off a leg so your body has less blood to cool. A bad idea.

Find and fix the root cause of the overheating. Either the engine is developing more heat than the cooling system can deal with (timing, head gasket, mixture - not likely with the PCM not throwing a code). OR your cooling system is lazy and not working as well as when it was designed. Clogged radiator, insufficient water pump flow, collapsing hose, insufficient airflow, fan clutch, insufficient opening thermostat.

Your thermostat must be fully open at 210-220 F. If it's not, just get a new one. If it is fully open, and you're still overheating in traffic, you have made your cool weather performance worse. And you have not fixed the root cause of the problem.

The GM designers might have been evil in some ways, but the vehicle is SUPPOSED to be able to cool itself in traffic at well over 100 degrees F.

Get a scan tool on the vehicle while it's overheating, and see if the commanded fan RPM is equal to the actual fan RPM. That's essential to understanding your real problem.
 

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2007 gmc
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Yes, find and fix the problem. You need the thermostat in there to help heat the truck up to operating temperature as fast as possible. Increasing the time to get to operating temperature will cost you MPG.
 

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2004 gmc
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As an amazing coincidence, I changed my thermostat out today because I didn't totally like the Scangauge data I was seeing last weekend towing the trailer up to 7000 feet.

79K miles, and on hill climbs I was seeing 220-225 degrees, and coasting downhill the ECT went as low as 170! That's not normal, and is evidence of overcooling due to thermostat sticking slightly open. 220 could be evidence of it not opening enough. That sort of bad data gets me concerned.

I won't be towing again until Wednesday morning, but a quick run to a short hillclimb at low ambient (75) got me 205 for a high. Coasting on a long freeway downhill got me 195. Most of the time it was 197-200 under many kinds of throttle conditions. That kind of data makes me sleep well at night!

The temp gauge needle was always locked at 210, but in the I6 we already know the PCM is lying to us. Have to get access to the raw unfiltered data to know the truth.
 

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2005 chevy trailblazer_ls
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I thought the cooler the better

This engine (like all modern engines) is designed to operate at a certain temperature.
I thought the cooler the engine the better? I mean to a certain degree. I know running the engine crazy cool is bad but they make so many products to help bring the engine temp down like bigger radiators and stuff like that. I was thinking of getting the cry02 system and running it from intake to radiator to tranny. But what we are saying is it's not a good idea to lower the engine temp? For people that tow a lot it seems like a good solution if you can keep an eye on the temps.
 

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2004 gmc
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Larger radiators allow you to throw more heat away to the air. It's still the job of the thermostat to regulate the water temp getting to the radiator. At low airflow from low driving speed, the fan will improve the airflow, but the primary item that sets the ECT is the thermostat.

Too low or high will upset the designs made by the combustion engineers as well as the metallurgists who design the aluminum and steel parts to operate with certain clearances at a certain temperature. Any deviation from that temperature thwarts the designers and could cause excess oil consumption, piston slap, etc. etc.

It's not a simple "cooler is better" equation anymore. If it was, GM would have put in 140 degree thermostats and massive radiators and not dealt with the materials problems that come with higher temps.
 

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2003 chevy trailblazer_lt
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Running an engine cooler longer at start up does not allow the O2 sensors to go into open loop mode, which causes unburnt fuel to get into the catalyst, there by destroying it and the O2 sensors, which in turn costs you more money.

That aside, you may look at swapping out the Dex-Cool. Google Evans NPG as a replacement for a water based coolant. If you live in a high heat area like Texas, Arizona or the like, you can attempt to find a thermostat that will open sooner, but you'd be better off with a higher flow unit rather than a lower temp unit as it will still heat up to the same temp eventually. Also you may need to have your computer flashed for the lower temp thermostat, many of the newer cars will kick up a check engine light.

Nother thing, clean the radiator between the AC unit. Vehicles tend to collect alot of crap between the two and folks don't clean it well enough due to not being able to see it. Sort of a out of sight out of mind type of deal.

Otherwise, everyone has given good advise so far.
 

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That aside, you may look at swapping out the Dex-Cool. Google Evans NPG as a replacement for a water based coolant. If you live in a high heat area like Texas, Arizona or the like, you can attempt to find a thermostat that will open sooner, but you'd be better off with a higher flow unit rather than a lower temp unit as it will still heat up to the same temp eventually.

I don't think I've ever seen a cooler thermostat for the I6 engine ever offer by any parts supplier. Anyone else seen one?

Also I doubt that changing to a different coolant would make a significant difference.

I changed my thermostat a few months back because it was under cooling. Going down long hills at freeway speeds would cause the temp. gauge to drop about 2 marks to the left of 210, and it was taking longer to hit the 210 mark in the morning.

As I've said before - after replacing it all is well. Drove to Arizona and back with 110+ degree heat up some pretty long hills on Interstate 8 (east of San Diego) and never saw it move off of 210.
FWIW, I replaced the factory Dexcool with fresh Dexcool. The engine and the radiator all looked like new.

Like Rayvoy and Roadie said - the o/p has a mechanical problem (water pump, fan clutch, etc) that needs fixed. Removing the thermostat is NOT going to fix it.
 

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2002 chevy trailblazer_lt_ext
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Discussion Starter · #14 ·
I keep reading the topic continually
But I can not post a replay because I was browsing through the mobile and there was a problem with the forum when i want to post any thing .

I thank you for your attention


Find the original problem and fix it, then replace the thermostat.
thermostat allready replaced 2 weeks ago , and so many problem fixed last 2 weeks ,
I've tested the water pump and fan clutch in the master gm service center -not the dealer- and did not show any errors or problems of the operation

Make sure that the fan is operating all the time with the a/c on. If things have not changed since I was in service, the fan should be on continuously in traffic with the a/c running. If you can get some one with a Tech2 to run through the test sequences, you should be able to tell easily if the fan is working properly. Also, when was the last time the cooling system was serviced? How many miles on the vehicle? There are too many things that can be causing the problem, you need to have some one diagnose.
This is what is surprising me !
And raises questions to me and the dealer, the fan is working properly
We have done tests to determine whether the fan is working in traffic and while driving or not and the result was that it was working
They have a laptop contected to my car and asked me to drive , i noted that he is watching through a special program , in the end he said that there is no problem.

the roadie.. Thank you for advice, and thank God I did not remove the thermostat.
by the way roadie is a reference to me and his advices can not be ignored.
 

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2002 chevy trailblazer_lt_ext
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Discussion Starter · #15 ·
Yes, find and fix the problem. You need the thermostat in there to help heat the truck up to operating temperature as fast as possible. Increasing the time to get to operating temperature will cost you MPG.
New information for me that there is a correlation between the MPG and temperature of the engine, I thank you value your feedback

but in the I6 we already know the PCM is lying to us. Have to get access to the raw unfiltered data to know the truth.
This calamity and this supports the idea of using external temperature sensors not conected to the BCM, did the obd2 support the current reading and unrestricted with BCM ?

It's not a simple "cooler is better" equation anymore. If it was, GM would have put in 140 degree thermostats and massive radiators and not dealt with the materials problems that come with higher temps.
Here there is some types of thermostats open at a temperature less than 86c ?
But I was afraid to use it.
 

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Western Canada Chapter
2003
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New information for me that there is a correlation between the MPG and temperature of the engine, I thank you value your feedback



This calamity and this supports the idea of using external temperature sensors not conected to the BCM, did the obd2 support the current reading and unrestricted with BCM ?



Here there is some types of thermostats open at a temperature less than 86c ?
But I was afraid to use it.
The SCANGUAGE tool connects to the OBDII port and will give you all the real data you need. You can buy it online.
 

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2005 chevy trailblazer_ls_ext
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2,667 Posts
I keep reading the topic continually
But I can not post a replay because I was browsing through the mobile and there was a problem with the forum when i want to post any thing .

I thank you for your attention



thermostat allready replaced 2 weeks ago , and so many problem fixed last 2 weeks ,
I've tested the water pump and fan clutch in the master gm service center -not the dealer- and did not show any errors or problems of the operation



This is what is surprising me !
And raises questions to me and the dealer, the fan is working properly
We have done tests to determine whether the fan is working in traffic and while driving or not and the result was that it was working
They have a laptop contected to my car and asked me to drive , i noted that he is watching through a special program , in the end he said that there is no problem.

the roadie.. Thank you for advice, and thank God I did not remove the thermostat.
by the way roadie is a reference to me and his advices can not be ignored.
Just curious, but how did you test the water pump?

I'd say if you are sure the water pump, fan clutch and thermostat is good - then it only leaves you a couple of possibilities. One is a bad radiator, or the other you have a bad head gasket.
We have a seen a couple of people with bad head gaskets lately, but not that many. Check some of the other threads where people had overheating problems.
 

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2002 chevy trailblazer_lt_ext
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Discussion Starter · #18 ·
Here in my city there is alot of "radiator repair and service workshops" . but when they see my radiator they don't want to do any thing , some one explain why to me ? because there is a pipe of power steering oil go inside the radiator . I want to take it out to cleaning inside the cells and water round but they refuse .

about the radiator size, there are local and global kinds can be adapted to work in any car and there is various sizes, for example, there is a three or four rows, but before thinking of replacing I will try to take it out and clean the inside maybe blocked or some thing , but how ?

by the way, front of tb is very close and there os no any space available to instal a second efan operating with a temp sensor between the grill and the ac radiator .
 

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Discussion Starter · #19 ·
Just curious, but how did you test the water pump?
the dealer test it and i dont know how . but i think .. the pressure at idle and at cold engine and hot engine .. am not sure but i will call him tomorrow and ask him :bonk:


thank you very mutch :thx
 

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2003 chevy trailblazer_lt
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Thanks for the correction Roadie, you are correct, I had it backwards.

Evans NPG isn't just a replacement coolant, it also runs under a lower pressure than conventional coolant. Pressure is part of what allows the coolant to not boil at the temps newer vehicles are running at. Anyways, it's just a suggestion for something to look at.
 
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