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Guerrero's take on H3 cooling

alrock

El Diablo
Staff member
Messages
10,442
Location
Scottsdale
I am Oscar, from Spain, my nickname here is Guerrero (my surname), I am going to post my investigations, current mod, and discussion about some wrong thoughts that is written here:

First of all, is that Hummer H3 i5 Cooling System DOESNT have problem, or something about undersized, I live in Spain where outside temps are usually in the 70ºF in average, a lot of humidity and in Spring and Summer we can see Outside temps climb from 90ºF to 110ºF temps in hot days of Summer, I travel a lot with my 2006 Hummer H3 3.5 to sahara desert in Maroc, doing desert dunes in 90ºF outside temperature, with stock cooling setup except Dexcool being replaced, and that is why I can tell that all the current and past cooling issues the majority of us experienced are due to TWO things:

-Dexcool Coolant Fluid: Dexcool is what is inside our trucks from factory, and from factory we received the 180ºF thermostat too...a lot of us experience in general 1/2 gauge temperature, but under high demand of power, or towing we can see 3/4 of the gauge...We here made the experiment with a 2008 Hummer H3 3.7 from a friend, with very low myles and 180ºF thermostat from factory and Dexcool about coolant. He usually saw 1/2 gauge except in long highway inclines, where the gauge climb to 3/4 (220ºF).....we flush and replace the Dexcool with Quimzel 50% Organic red colour coolant, we made the experiment again in the same highway and driving than before and the gauge NEVER climb over 1/2 of the gauge. I made the same experiment with 3 Hummers h3 more here, and the same result (only with the ones with 180ºF thermostat) so for me its clear, the system itself is very capable, the problem with running 1/2 and sometimes running 3/4 under high demand is due to poorly flow dexcool, if you flush and replace dexcool you will achieve a very stable temperature range of 190 to 195ºF water temperature with factory assembly line 180ºF.

-Thermostats: GM decides to replace factory assembly line 180ºF oem thermostat, with 195ºF thermostat in something like 2010 or 2011 I believe, with this thermostat Hummer H3 is ALWAYS running in the 200-210ºF coolant temp range (No matter what you do), if you let the Dexcool with this 195ºF thermostat the temp range usually opens to 220 or 225ºF under high demand.

Responding to EndeavoredH3 I tried the shim method in my 195ºF GM thermostat and achieve a little lower temp range, from 200 to 205/207ºF coolant temp range, so is a improvement and stabilizies the temp a little but is not a definitive solution to the H3 195ºF thermostat problem.

So...what is the solution?

Well first step is to consider how the stock Thermostat Housing is mounted, someone here said that OEM thermostat is mounted in the Outlet Hose of Engine, so its better to control temperature....well that is totally wrong..the Outlet Hose where OEM thermostat is attached is the OUTLET HOSE OF RADIATOR, meaning that is the INLET HOSE OF ENGINE, where cooler coolant reaches, making the thermostat always delayed respect of current engine temperature, that equals to a hotter coolant in engine. This mean that a Thermostat placed in the REAL OUTLET HOSE OF ENGINE (UPPER HOSE) will control better temperature of coolant, because the Hot coolant from engine reachs the thermostat, opening faster than placed in Lower Hose like OEM is.

So despite that GM introduce again the 180ºF thermostat (not going to happen) I am going to post my own solution, based in the solution of some guys in **** forums:

-SUSTITUTE CURRENT THERMOSTAT (removing the thermostat from oem housing and eliminating anything that cut flow), for another 180ºF one with its own housing, placed in the UPPER Hose (outlet hose of engine):

g1-L.jpg


I selected Jegs 53260K1 Inline housing Kit with thermostat and clamps: https://www.jegs.com/i/JEGS/555/53260K1/10002/-1

To Mount this Inline Housing kit you need to first, remove OEM thermostat, and empty the housing, here is a picture of a thermostat housing empty next to a one not empty:

g2-L.jpg

g3-L.jpg


After you empty the OEM Thermostat Housing placed in the lower Hose, you just reinstall it with new oring and install the lower hose back into the radiator, now you need to move to the UPPER HOSE, remove hose and take out metallic Outlet Water from Engine (I installed exhaust headers at the same time, if not, the lower bolt in the outlet water housing is difficult to remove), and you need to cut it almost 3 inch to allow enough room to place new Inline thermostat housing:

g4-L.jpg

g5-L.jpg


After you cut it out, reinstall it, and place the NEW THERMOSTAT HOUSING cutting and adapting the new hose, so it makes the turns allowing the engine movement (I bough a longer hose from acdelco that rockauto offer, and cut that hose, not the OEM used one). VERY IMPORTANT to place the THERMOSTAT IN THE CORRECT DIRECTION, facing it considering that the flow of coolant in the UPPER HOSE, goes from the engine to radiator.

An this is the result:

g6-L.jpg

g7-L.jpg


I installed at the same time Exhaust Headers and a efan conversion, using DUAL FAN SETUP FROM A DODGE MAGNUM V8 (2008) or Chrysler 300c v8, need to cut and adapt the shroud to radiator, and use some screw to attach it, very low amp draw (20 amps of both fans) and g8
g9-L.jpg





These are ORION HEADERS, awesome finishing and performance after install, in that picture you can see it next to my previous setup, the stock exhaust manifold gutted with some exhaust wrap for lowing exhaust noise that removing catalytic made.

g8-L.jpg

g10-L.jpg



g11-L.jpg

g12-L.jpg

g13-L.jpg


This is the EFAN conversion setup that I used, based in EndeavouredH3 is experiences, and the experiences of one guy in Facebook that has this same setup in a Hummer H3 v8 configuration with 500hp and no cooling issues.
The Fans is a APDI PRO #6015103 and the fan controller is a Davies Craig #0444, amazing fan controller with programmable temperature to start and with the feature of one fan start and after 5 seconds start the second one (like soft start).

Finished engine bay looking:

g14-L.jpg

g15-L.jpg


g16-L.jpg




WELL! AND THIS IS THE RESULT:

First picture is the normal TEMPERATURE WITH OEM 195ºF thermostat (with shim, to try to open it a lower temperature) and with STOCK CLUTCH FAN:

g17-L.jpg


This second picture is THE CURRENT temperature, after INLINE THERMOSTAT MOD, EFANS and exhaust header:

g18-L.jpg

Like you can see the improvement is HUGE with stock radiator, and stock water pump and hoses, all of this is due to thermostat (considering that a clutch fan is always better about cooling that a efan setup)

Yesterday I datalog my Hummer h3 for a retune due to new mods, and drive it very hard, at WOT, highways inclines, traffic, city and temperature NEVER climbs over 190ºF, so this is totally a WIN. I need still to test this in Maroc Desert with 90ºF or more of exterior temperature in October, or this Summer here, where temps climb up to 110ºF sometimes.

Here are some pictures of my truck, with a lot of other mods, 2.0 Fox shocks, Moog parts, Tranny upgrades, outfitter design kits, etc, that I can talk about with some new threat:

g19-L.jpg


g20-L.jpg


g21-L.jpg


I can talk too about Performance upgrades and result, but you can imagine than differences are awesome, with 33 inch tyres is in the low 9 seconds from 0 to 60 mph, before the necessary retune, so I expect this 3.5 to so a high 8 seconds from 0 to 60 mpg after retune, we will see.

My truck is prepared for fast desert driving, reliability and performance doing offroad desert, some trails, and daily driving.
 

Guerrero

Well-Known Member
Messages
124
Location
Spain
Moved to new thread as requested though I accidentally deleted it in the process. Hope I recreated it correctly.


Thanks so much Alrock!!

Yes, everything seems perfect! :)

I have a lot of research about h3, in all my years and always wanted to create a massive thread about: Commons Problems and Solutions with h3 - Performance Mods for a definitive fast, strong and reliable stock style h3

I will take patience and do something in the near future, again thanks!
 

Mr_Rich

Well-Known Member
Messages
636
Location
High Desert & Santa Maria
This was a great, interesting write-up on H3 engine cooling. Some of the mods wouldn't be legal in Calif. or some areas of the US unfortunately. About all I can add is that engine cooling was never an issue on my M5-equipped 3T, even in 117 degrees going through Needles, Calif. in the summer. The temp needle always stayed below the second hash mark and I also monitored the functions with a diagnostic tester.
 

Guerrero

Well-Known Member
Messages
124
Location
Spain
Do you have a link to the coolant used?


http://catalog.quimxel.ae/index.php?id_product=257&controller=product

That is one link, the Antifreeze made by Quimxel is a Spanish product I think, without international sales I think... nevertheless is not necessary to use that exactly product...there are a lot of Organic Antifreeze at 50% in red colour out there

Is just to avoid using Dexcool (is a awesome brand about durability but I tested that is not any good about flow)

Hope this help!
 

Guerrero

Well-Known Member
Messages
124
Location
Spain
Maybe this is going to sound missrespectful for somebody but are totally not my intention...

But Why the hell are people telling others with an H3 i5, that 3/4 of the gauge (220ºF) are a normal condition for an H3 when its TOTALLY not???

The fact that H3s support very well those temps doesnt mean that is a ''normal condition''.....even some guys are totally convinced that is normal because in some page in the owners manual there is a temperature gauge figure showing 3/4 (without any text supporting it, and in my opinion that figure only moves the needle to show the ''middle icon'' or figure....anythig about ''normal temperature''
EVERY h3 i5 here that is carrying a factory assembly thermostat (180ºF) without dexcool coolant, using another stuff is running a 1/2 of the gauge, even in 100ºF outside temperature...my h3 is running an aftermarket inline housing with the 180ºF and dual efan setup (less powerful and efficient than a clutch fan, and is always in the middle of the gauge...(except some highway hills, where the temp climb some ºF degrees up but almost nothing))

Other thing is that an H3 carrying a 195ºF thermostat is usual to have a 5/8 of temp gauge, but that is not what h3s are design for from factory...


This usually commented thing about h3s being normal to run hot just make me nervous :)

What is your opinions guys?
 

amrg

Well-Known Member
Messages
2,317
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220* is normal, or the new normal (since 2005 at least). Higher engine temps means fuel burns better, less emissions, more eco friendly. If you run straight water and a 14 psi cap, your engine doesnt over heat until 254*. With 50/50 coolant, 265*. With a 17psi cap, you can hit 274* before boilover. So from an engineering standpoint, you still have 45* left to overheat (from 220*) and most people see those in the summer.

Sent from my SM-G960F using Tapatalk
 

Guerrero

Well-Known Member
Messages
124
Location
Spain
220* is normal, or the new normal (since 2005 at least). Higher engine temps means fuel burns better, less emissions, more eco friendly. If you run straight water and a 14 psi cap, your engine doesnt over heat until 254*. With 50/50 coolant, 265*. With a 17psi cap, you can hit 274* before boilover. So from an engineering standpoint, you still have 45* left to overheat (from 220*) and most people see those in the summer.

Sent from my SM-G960F using Tapatalk


I understand the point about the less emissions and more eco friendly....but that is all...about the coolant temperature is different the concept of water boiling, than dangerous temperature to cooling system and engine components..

And dont really understand the point :whaa: all h3s were DESIGN from engineer to work in the middle of the gauge...that is a 190ºF (with a 180ºF water termostat opening temperature), all h3s new from assembly line runs in that temperature...only time makes the system to work harder (because dexcool, dirty radiator or bad thermostat/clutch fan in my opinion) and begin to run in the first 210...then 220ºF ..so despite that maybe the engine run a little more efficient with the 195ºF thermostat, that makes the H3s ''new normal temp'' sitting in the 200 - 205ºF of coolant temperature..not 220ºF

Having more than 240ºF of temperature in an cooling system is too close to damage engine components or cooling system components in my opinion

I travel a lot to hotter desert climates and having a 3/4 of the gauge is not an option with 110ºF outside, and when engine is running at 220ºF you stop it and the temp climbs even to 230 or 240ºF mark...that is not acceptable

At first I had a 1/4 of temperature all the time in the 2009 year, that was due to bad thermostat....in that moment I believed what a lot of people said about h3s running normally in the 220ºF mark and cooling system not being capable of cold it more..but think about it....a bad thermostat opening sooner forced my engine to run 1/4 of gauge even in desert Dunes in sahara....so is not the system itself, is the thermostat.

H3s i5 were design to work with a 180ºF thermostat from engineer ''design table'', so my point is, that ''normal temperature'' is at the middle of the gauge...GM just realizes that sitting a little warmer decrease emissions..and they changed thermostat

I always talk about my experience, but every h3 here with a factory assembly thermostat (180) in good condition, only with a coolant flush and change makes the gauge to see only 1/2...so ''normal'' is that point, a little warmer (5/8 of the gauge) with the 195ºF thermostat..
 

amrg

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My 2009 H3 runs below half on the needle up to 107* c, half is 108*c up to 120*c then starts climbing after that. So the engineers did change how the needle works, its just Hummer didnt servive enough for alot of people to see it. My friends 2009 H3 does the same. Dont stress alot about it.

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alrock

El Diablo
Staff member
Messages
10,442
Location
Scottsdale
a bad thermostat opening sooner forced my engine to run 1/4 of gauge even in desert Dunes in sahara....so is not the system itself, is the thermostat.
My experience has been different. I've had a stuck open thermostat and the only difference was that it took longer for the engine to heat up. After it was warmed up, it operated in the normal/typical engine operating temps.
 

Guerrero

Well-Known Member
Messages
124
Location
Spain
My 2009 H3 runs below half on the needle up to 107* c, half is 108*c up to 120*c then starts climbing after that. So the engineers did change how the needle works, its just Hummer didnt servive enough for alot of people to see it. My friends 2009 H3 does the same. Dont stress alot about it.

Sent from my SM-G960F using Tapatalk

mmmm...interesting...I wonder is that case was only in the H3 sold in UAE or the same for all 2009 and 2010 H3s!

Its the same system than BMW, the needle is not a direct temp lecture....is like a reference...in 2006 - 2008 H3s the needle is very accurate about temps...sometimes the needle takes a while to move, so its accurate with a error of 1 to 2 ºC..
In the BMW the needle stays in the middle between 90 and 104 ºC I think

Damm...120ºC is to much for me to start climbing :giggle:
Despite that...I still think that a 190ºF stable temperature is preferable in hot climates or desert running than 210 or 220ºF, because of the fact of the H3 not having electric water pump, so when you stop a h3 with 220ºF coolant, and look at the temp, that continuous to climb even further than 230ºF or more....that is in the dangerous area for components for me....maybe is not a direct failure, but a lot of stress to components that wear them faster..
 

alrock

El Diablo
Staff member
Messages
10,442
Location
Scottsdale
When I stop my H3 in 100F+ temps for extended periods, I keep the RPMs around 1500 to 2000 to get the fan to move enough air across the radiator to bring the temps back down. I tested this a few weeks ago on a 110 degree day. Temps got above 3/4 when idling for a long time and a/c cut off. After about 2 minutes of ~1800 RPMs, temps were normal and a/c was cold again.
 

Guerrero

Well-Known Member
Messages
124
Location
Spain
When I stop my H3 in 100F+ temps for extended periods, I keep the RPMs around 1500 to 2000 to get the fan to move enough air across the radiator to bring the temps back down. I tested this a few weeks ago on a 110 degree day. Temps got above 3/4 when idling for a long time and a/c cut off. After about 2 minutes of ~1800 RPMs, temps were normal and a/c was cold again.


Yes, I tested the same in hot weather, and I was doing the same before my current mods.....in summer or desert, while idling climb to 1500 rpm or 1800 rpm to lower some degrees...but I was tired of it :)

In my previous message I refer that when you turn off the engine, and check temperature, in hot climate, temp start climbing 10 or 20ºF more than before turn off....that is a problem in my opinion..

With my current inline 180ºF thermostat, temps always are sitting a little below half of gauge in summer (100ºF some days right now), and in highway hills, at half of gauge.....and that considering that right now I am using dual efan setup...less powerful than a clutch fan

I am more relaxed and less worried about temps right now, and that for me, worth the money on this setup!
 

Guerrero

Well-Known Member
Messages
124
Location
Spain
How did this setup hold during the summer months?

This setup combining new Thermostat Housing with 180ºF temperature thermostat and dual efans is adequate for Summer but under high demand or highway climbs, the temp rise until 195-200ºF due to low Efans capacity of cooling, being perfect at low speed or 4x4, I tested the Clutch fan again and that resolve the Highway climb problem under high demand of power, so the perfect setup will be those dual efan puller and add another efan pusher powerful for the I5 application!

Right now I have a 2008 Hummer H3 alpha, and sold my previous H3 i5 with the clutch fan, so I tested those dual efan with a powerful pusher in front in the Alpha and is not enough to cool down the V8 in highway or under high demand of power..
Next I will test the Thermostat relocation in the alpha too, and after that the Efan from Camaro SS that AMRG commented in his built thread! I need to discuss with him a few aspects of that fan (possible pcm configuration and how he addapted the shroud)

Guerrero
 

amrg

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Hey dont relocate the tstat on the Alpha, there are many aftermarket options you can use (unlike the I5). Check summit racing, you can go all the way down to 140*. But being in spain, the winter there is cold compared to Qatar and at 140* it will take a long time to warm up the engine setting an engine warning light, unless you change it in the tune. (Iirc the engine should hit ~160 within 2 mins from startuo to go into closed loop, if it takes longer it will assume you have an issue and illuminate the engine light)

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Fastsspr

Member
Messages
7
Location
NV
The thread is very informative. I bought a 06 H3 I5 and didn't know about what GM did with the replacement from 180 to 195 thermostat. So I replaced everything in my cooling system to make the truck reliable to run into brutal summer desert temp in Nevada up to 125 F. Now I noticed that the gauge is going up the 3/4 mark in winter. In my book that is not acceptable. So I going to receive my inline thermostat this coming Monday to relocate the thermostat. Now my question is, how the coolant flow in this I5 engines? The inlet flow into the block is by the top of the radiator or the button? Is to know how install the new inline thermostat.

Thanks for all the information.
 

ad74710

Probationary Member
Messages
1
Location
Abu Dhabi
Regards engine thermostat, there is a better option is to machine the original thermostat housing and install hyundai 25500-2b000 thermostat. It is 82 degC and constant flow that stabilize the temp below middle line.

Very cost effective and permanent solution.

I am highly recommending to weld additional port for sensor to serve e-fan conversion.
 

Fastsspr

Member
Messages
7
Location
NV
Regards engine thermostat, there is a better option is to machine the original thermostat housing and install hyundai 25500-2b000 thermostat. It is 82 degC and constant flow that stabilize the temp below middle line.

Very cost effective and permanent solution.

I am highly recommending to weld additional port for sensor to serve e-fan conversion.


You have a picture of the thermostat housing machined? The modification of the housing have to be in a machine shop or can be done with grinder in a garage?
Thanks so much for the information.
 

Jeepwalker

Well-Known Member
Messages
857
Location
WI
Interesting thread.

Has overheating been an issue? I've wheeled in some hot Moab summers with my I5. 110*F and higher, middle of nowhere, AC on, all stock, ...never noticed any overheating.
 

Fastsspr

Member
Messages
7
Location
NV
Interesting thread.

Has overheating been an issue? I've wheeled in some hot Moab summers with my I5. 110*F and higher, middle of nowhere, AC on, all stock, ...never noticed any overheating.

I not have overheating problem but the engine is right at the border to over heat.
My problem is when I bought the truck it had the 180F thermostat in it and the temp was in the middle of the gauge all the time in a 90deg. weather. Them I decided to completely redo the cooling system without know the mod. that GM did with thermostat. I replaced every single part of the cooling system with new ac delco parts and now my gauge is in the 3/4 all the time and it was not there when I first bought the truck. I want to maintain the temp. at 1/2 gauge reading.
 

Mikey13b

Member
Messages
6
Location
Australia
This setup combining new Thermostat Housing with 180ºF temperature thermostat and dual efans is adequate for Summer but under high demand or highway climbs, the temp rise until 195-200ºF due to low Efans capacity of cooling, being perfect at low speed or 4x4, I tested the Clutch fan again and that resolve the Highway climb problem under high demand of power, so the perfect setup will be those dual efan puller and add another efan pusher powerful for the I5 application!

Right now I have a 2008 Hummer H3 alpha, and sold my previous H3 i5 with the clutch fan, so I tested those dual efan with a powerful pusher in front in the Alpha and is not enough to cool down the V8 in highway or under high demand of power..
Next I will test the Thermostat relocation in the alpha too, and after that the Efan from Camaro SS that AMRG commented in his built thread! I need to discuss with him a few aspects of that fan (possible pcm configuration and how he addapted the shroud)

Guerrero

Are you running the standard alternator?
 
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