NEED HELP Overheating issue with AC ON!

ghost_leader07

Original poster
Member
Dec 18, 2019
152
UAE
Hello,

I apologize in advance for the lengthy post.

I have a 2004 Trailblazer 4.2L with 97k miles on it and I've been having some overheating issues recently.

I live in a hot environment my temp gauge is usually sitting below 210F but lately it's been going 2-3 ticks above 210F when AC is ON while idling but goes back around 210F once i get moving. Today i decided to go for a quick drive (very hot today around 105F) it was 30 min drive my temps were in the normal range so i parked over and left the engine and AC running for about 10 minutes when I got back i found my temp gauge right at the 4th mark once i started moving it started to go down rapidly to 1-2 ticks above 210F. Went home parked the truck and heard burping noise coming from the overflow and was filled to almost the top with coolant.

Here's a clip:

A list of the things done on my truck:

-Replaced radiator and cap
-Replaced fan clutch (non ACDelco part)
-Replaced ECT sensor (ACDelco part)
-Replaced thermostat (ACDelco part about 2 years ago)
-Transmission cooler installed before AC condenser)
Please note that i only have a P0171 code which I'm working on fixing but it's a PITA.


Your help is needed and greatly appreciated.
Thank you in advance.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Does it seem to improve if you are moving? When it gets hot, do you hear the fan pulling more air? You should test the fan:

How to test the electro-viscous fan clutch

-Replaced fan clutch (non ACDelco part)
What brand? If it's a CCC (Cheap Chinese Clone), it may already be dead.

Did you check the concentration of the coolant and how old is it? Best would be 50/50.

Try to hose down the radiator and A/C condenser to clear out any dirt and bugs. Airflow could be blocked.
 

Eric04

Member
Dec 3, 2014
392
West Michigan
I procrastinated too long with the fan clutch on my 2004. I knew this when I was running errands on a hot day and upon a restart my temp gauge jumped several ticks past 210. It did return to normal range once I got moving but I soon after replaced the clutch and finally heard the roar of engagement again. I got away with it longer than I should've since Michigan is only hot for a few months per year.
 
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ghost_leader07

Original poster
Member
Dec 18, 2019
152
UAE
Thanks for the reply!
Does it seem to improve if you are moving?
Yes it does. As soon as I got moving It went from 4 ticks above 210F to 2 ticks in less than 3 minutes.

When it gets hot, do you hear the fan pulling more air?
While idling the fan remain at low speed no loud ramp up at least nothing that I've heard but while driving i did hear the fan go louder for few seconds before slowing down.

Thanks for the link I'll do the tests and let you know.

What brand? If it's a CCC (Cheap Chinese Clone), it may already be dead.
It is a CCC i bought it back in 2018 for $60 and seemed to run fine, it had decent reviews still sales today here's Amazon link:

It doesn't sound like fighter jet engine only at cold start-up before going quieter as engine warms up.

Try to hose down the radiator and A/C condenser to clear out any dirt and bugs. Airflow could be blocked.
It was the first thing I checked and it looks pretty clean between the rad and condenser but I'll hose down just to be sure however i do have a transmission cooler installed at the front but i doubt it can cause any issues maybe?
 

Joe_67

Member
Aug 9, 2022
56
Central Virginia
My money is on the fan clutch. (Sometimes - or maybe even often/usually it does pay off in the long run to spend more in the short run).

Just spitballing on the A/C relation. One is that it's coincidental - if it's August in Egypt isn't the A/C basically always on? Other than that, the compressor does put extra load on the engine (i.e. more heat), and the fan had to ramp up to cool both the radiator and the condenser. Still points to the need for more fan speed and thus the fan clutch.
 
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Mooseman

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25,262
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ghost_leader07

Original poster
Member
Dec 18, 2019
152
UAE
UPDATE:
I've did some testing on my fan clutch following @Mooseman guide and did the following:

-Started the engine and let it reach operating temp the fan clutch ramped up for few seconds then slowed down.

-turned on the AC and let it run for few minutes, i tried to stop the fan using a rag and i was able to stop it completely and easily, i held it for few seconds didn't feel any tugging (should I hold it for longer than 10 seconds?)

Temperature remained within range for a while but after doing the fan test a couple of times with AC on my temps slightly went up (dead on the center) during all of my testing i was able to stop the fan with zero effort whether the ac on/off the fan felt like spinning freely most of the time.

One thing i forgot to mention that my fan clutch do ramp up and spin faster for short periods during the higher rpm i was still able to stop it easily. Never felt any tugging but i did feel a higher airflow when it's 'engaged'

Does this confirm my fan clutch is bad? Is there is anything else i should do before ordering a new clutch? Definitely going with ACDelco part this time.

UPDATE #2:
I wasn't sure how long should I be holding the fan and i couldn't wait for someone to reply so i went ahead and did the test again but this time i held the fan for about 40 seconds with AC on i felt a slight tug it was barely noticeable though but i definitely felt it. Also while holding the fan the ac compressor was acting up turning on/off and my rpm became somewhat erratic that only happens when i hold up the fan.

Engine temp was creeping up a little so i reved up the engine to 2000rpm and my fan clutch ramped up it became loud for few seconds then goes down...i don't hear the fan engaging while the ac on.

I'd really appreciate it if someone could shed some light on this.
 
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Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Sounds like it's working if the fan is ramping up but not staying ramped up. However it shouldn't be that easy to stop if it's really working especially of it's been running for an extended period of time to give the silicone lube in the clutch time to get warm and move around.

Here's an idea. Try the same tests but with the clutch unplugged. If it does the same thing, I'd condemn it. And since it's a CCC, I wouldn't have much confidence in it to work as per specs.
 
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ghost_leader07

Original poster
Member
Dec 18, 2019
152
UAE
Sounds like it's working if the fan is ramping up but not staying ramped up. However it shouldn't be that easy to stop if it's really working especially of it's been running for an extended period of time to give the silicone lube in the clutch time to get warm and move around.
Yeah it's very easy to stop whether the ac on/off even while it's ramped up i can stop it easily. I noticed that it only ramps up at 2000rpm is this normal?

Here's an idea. Try the same tests but with the clutch unplugged If it does the same thing, I'd condemn it.
OK I'll try that and let you know. what sort of behaviour I'm looking for while it's unplugged?

And since it's a CCC, I wouldn't have much confidence in it to work as per specs.
Yeah I'm not very confident with it, especially for something 5 times cheaper than OEM surely there's a cost cutting somewhere or it can be that OEM part are extremely overpriced?

I found this on Amazon for $362
GM Genuine Parts 15-40133 Engine Cooling Fan Clutch https://a.co/d/66p8BOh
 
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Mooseman

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25,262
Ottawa, ON
OK I'll try that and let you know. what sort of behaviour I'm looking for while it's unplugged?
Total freewheel, no ramp up at all. However, if it has failing bearings, it could drag the fan a bit but let go at higher RPM.

Yeah it's very easy to stop whether the ac on/off even while it's ramped up i can stop it easily. I noticed that it only ramps up at 2000rpm is this normal?
It should keep ramping up and pull more air as RPM climbs, especially as it gets hotter. It should not be easy to stop.

I found this on Amazon for $362
GM Genuine Parts 15-40133 Engine Cooling Fan Clutch https://a.co/d/66p8BOh
Hole crap! Instead, get this one. It's the original supplier to ACDelco and less than half that price:

 
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aaserv

Member
Dec 1, 2019
408
N of Baton Rouge, La.
That Mahle / Clevite is the 1 I bought 6 weeks or so ago and I dont believe its the actual Behr of old. It looks just like the clones from EBay and in limited use so far Im overheating on 90+ deg days with the A/C on. It may be OK , hopefully some others will have better results with them but so far Im not pleased with it at all. Will return to Rock Auto 1st chance I get and hopefully have better results from the replacement but not getting my hopes very high from what Ive seen out of this first 1...

Rock has that GM original for $245
 

Mike534x

Member
Apr 9, 2012
894
If you aren't planning on doing any sort of towing, I'd say forget dropping the cash on the $350 AC Delco unit and just give the Hayden 3200 a try. Its not as good as the OEM one, but all things considered its still most likely better then any of the non-name brand ones out there and will still provide enough adequate cooling to where you shouldn't have to worry about overheating issues.
 

aaserv

Member
Dec 1, 2019
408
N of Baton Rouge, La.
Actually I was just reading the most recent Amazon reviews of the ACD unit and it appears that ACD is now shipping the Hayden unit as its OEM replacement..
Dont forget also to ck the local U-Pull for good condition Behr units.
 
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Mooseman

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Dec 4, 2011
25,262
Ottawa, ON
If you aren't planning on doing any sort of towing, I'd say forget dropping the cash on the $350 AC Delco unit and just give the Hayden 3200 a try. Its not as good as the OEM one, but all things considered its still most likely better then any of the non-name brand ones out there and will still provide enough adequate cooling to where you shouldn't have to worry about overheating issues.
I have to agree with that. Hayden aren't the best but aren't bad. However, if you're actually living in Egypt (that's what your profile says) or some other super hot region, I would stay with the ACDelco or real Behr.

Another option is to go with the thermal version for 08-09 and have the PCM tuned to turn off the codes for it. It's GM part# 25816289. I had the Hayden version in the Saab with the 5.3L but I did experience elevated temps while towing in 30c+. However, the logistics and costs of getting your PCM tuned (we usually use lime-swap.com in the US for $99 + your shipping) may negate any savings from the cost of the lower priced thermal clutch.
 
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ghost_leader07

Original poster
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Dec 18, 2019
152
UAE
Total freewheel, no ramp up at all. However, if it has failing bearings, it could drag the fan a bit but let go at higher RPM.
OK. So i did the test and came up with interesting results.

Engine was at operating temp with AC on unplugged the clutch connector and it was freewheel the whole time even at 2000RPM it didn't ramp up and it was easy to stop. However after plugging it back while idling with the temperature rising the clutch would engage only when i rev up the engine to ~2000RPM if I didn't rev up it wouldn't engage even though the temps are going up but if rev it to 2000RPM it would ramp up and cool the engine instantly I did it a couple of times and i can confirm the fan clutch would engage for about 10 seconds but only if the temp are above center while revving up the engine at idling it wouldn't ramp up by itself. All the testing was done with AC on.

I'm by no means an expert but could it be that the ECM is not commanding the fan clutch to engage at low rpm or something wrong with the sensor inside the clutch?

I've also read something about a software update to the ECM regarding the fan clutch I'm not sure though.

Follow-up:

Did more testing but this time temps got a lot hotter. During the testing the fan clutch engaged once or twice but stopped ramping up altogether my temps started climbing and reached about 4 mark above the center before turning the engine off, my AC was on and was revving at 2000rpm for 2 min but it didn't engage.

I'm starting to think that the clutch's operation is intermittent 'causing my overheating issues but I'd like your input on this.
 

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Mooseman

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Dec 4, 2011
25,262
Ottawa, ON
Even at idle, the fan should be pulling a lot of air and you would see, feel and hear it. I think the clutch is not operating properly at idle.

There was an update or two but that was mostly for 02 and possibly 03 and was to address a noise issue and transmission shifting related to the fan clutch. If it operated properly before with the original clutch, this is not the issue.

Replace that clutch.
 
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aaserv

Member
Dec 1, 2019
408
N of Baton Rouge, La.
Yea the update was for 03-04. What Ive found is the replacement clutches are very slow to respond to the calls for different fan speeds. And on these 360's the speed is varying almost constantly.
 
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Mike534x

Member
Apr 9, 2012
894
My clutch is pretty much working like the OPs, minus the overheating portion. Despite being the original 213k Behr, the clutch isn't engaging resulting in poor airflow going through the condenser. Just looking at it I can see it's not spinning fast enough. Mines an oddball compared to how everyone else's is.

Actually I was just reading the most recent Amazon reviews of the ACD unit and it appears that ACD is now shipping the Hayden unit as its OEM replacement..
Dont forget also to ck the local U-Pull for good condition Behr units.

Was it for the thermal AC Delco clutch? I posted a review/pics on here before submitting it Amazon. I can't confirm for sure if AC Delco is substituting in the Hayden units since it was just one order, but it seems fairly likely if they aren't selling them new anymore. (At least for the 08-09 years while the EV ones can still be purchased).
 

ghost_leader07

Original poster
Member
Dec 18, 2019
152
UAE
Even at idle, the fan should be pulling a lot of air and you would see, feel and hear it. I think the clutch is not operating properly at idle.
I can feel it moving air but not sure if it's a lot it's freewheeling 90% of the time especially after my second test where it didn't engage despite having high temperatures and while revving at 2000RPM.

If it operated properly before with the original clutch, this is not the issue.
I've never had any overheating issues before replacing the fan clutch with the CCC, I had replace it when it seized up and started to roar all the time, before that it was running very cool due a stuck open thermostat which i didn't realize back then but it was replaced with an OEM ACDelco thermostat later.
 
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ghost_leader07

Original poster
Member
Dec 18, 2019
152
UAE
Yea the update was for 03-04. What Ive found is the replacement clutches are very slow to respond to the calls for different fan speeds. And on these 360's the speed is varying almost constantly.
I'm pretty sure my 04 hasn't been updated but it's impossible to update it here because we don't have a dealer with GM equipments.

What about getting GM genuine fan clutch will i still need the update?

Can PCM of NC do the update if i send my PCM? I'm thinking of getting a tune up as well.
 

Mike534x

Member
Apr 9, 2012
894
PCM of NC and Limequat will both be able to update the PCM (I know PCM of NC was able to install the updated GM software when I had my 02), and delete the fan clutch codes. So you'll be able to use a thermal one if you want to switch from the EV style to thermal while getting it tuned to your liking as well.

I'd still wager your fan clutch is the issue. Mine had slight resistance when doing the test but upon letting it go it just freewheels and doesn't spin back up to speed. Considering the costs, and the problematic nature of the EV clutch I would honestly just change to a thermal one and never worry about it going bad again.
 
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Mooseman

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Dec 4, 2011
25,262
Ottawa, ON
PCM of NC and Limequat will both be able to update the PCM (I know PCM of NC was able to install the updated GM software when I had my 02), and delete the fan clutch codes. So you'll be able to use a thermal one if you want to switch from the EV style to thermal while getting it tuned to your liking as well.
Remember, he's in Egypt so that would present an issue of shipping it and the down time while it has no PCM, which could be months.

I don't think you need the update. It only addressed issues not related to overheating.
 
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ghost_leader07

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Dec 18, 2019
152
UAE
Remember, he's in Egypt so that would present an issue of shipping it and the down time while it has no PCM, which could be months.

I don't think you need the update. It only addressed issues not related to overheating.
Thanks for considering my situation. However I'm planning on sending my PCM to PCM of NC for tuning i read good stuff about it which leads to my question about going thermal clutch per @Mike534x suggestion , is it a direct swap?
 

mrrsm

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You've listed this as having been R&Rd in your initial Posting of "What has already been done..." But jik things went sideways with the ACDelco Radiator Cap as happened in THIS Video... it might be worth pulling the Cap again and going over it with a Bright Flashlight searching for any hidden failures in design or manufacture:

 
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Mooseman

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Thanks for considering my situation. However I'm planning on sending my PCM to PCM of NC for tuning i read good stuff about it which leads to my question about going thermal clutch per @Mike534x suggestion , is it a direct swap?
It is a direct swap. However, I suggest using http://www.lime-swap.com/ instead. Cheaper and @limequat knows his stuff with this engine and can basically do the same as PCMofNC.
 

ghost_leader07

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Dec 18, 2019
152
UAE
You've listed this as having been R&Rd in your initial Posting of "What has already been done..." But jik things went sideways with the ACDelco Radiator Cap as happened in THIS Video... it might be worth pulling the Cap again and going over it with a Bright Flashlight searching for any hidden failures in design or manufacture:

Thanks for the R&R, i have replaced the radiator cap recently using an ACDelco part, i don't have bubbles per say just burping in the overflow tank which happened only twice (including today) with engine temp gauge reaching about 4 marks above 100°C, i think the cause is due overheating and coolant expansion but you'd have a better idea than me technically.
 

aaserv

Member
Dec 1, 2019
408
N of Baton Rouge, La.
You can go to .... https://tis2web.service.gm.com/tis2web/ there you can input your VIN# and it will list all the available updates for any GM software.

The problem with getting an "original" GM clutch fan is they were not made by GM or AC Delco . They were made by BEHR company. Unfortunately BEHR was bought out recently by MAHLE/Clevite and its my belief after having purchased the "new" BEHR that they are BEHR in name only. They appear to be identical to a $69 knockoff fan i bought off EBAY awhile back that wouldnt work straight out the box.
Cking the recent reviews of the fans sold by GM on the Amazon website it appears GM agrees with me also as they are shipping the HAYDEN brand which some people have had success with.

What IMO is the problem with the replacement fans is on most vehicles the fan pretty much runs at 2 or 3 speeds and the cooling system can cover for variations in the speeds. Envoys cooling systems are the bare minimum required to do the job, the fan speed is almost constantly being changed by the computer and these fans response times to these changes are just to slow. Due to lack of space the Envoy radiator is a single row that just isnt efficient enough to cover for the fan not pulling hard enough. That is why the major complaints GM received when producing these models was how loud the fans were. It was a constant problem that was somewhat but not totally solved by the non-electric "thermal " clutches.

I am not totally convinced that using the Hayden or switching to the thermal clutch will solve the problems for owners like myself who live in 90+ degree climates for 5-6 months out the year. I deal with overheating issues ANY time I drive my car when its over 90 degs outside. And close to 100 forget it, I cant go 10 miles from my house. Ive done and tried everything BUT the software update only because I dont trust any of the area dealerships to do it and I cant find any independent shops who have access to the GM software. I know of 1 that does but its run by a guy who is hard to deal with and I just havent begged them hard enough to do it for me yet.

Its looking more and more like we are going to have to find an upgrade to the radiator somehow someway as getting a reliable fan clutch may be a thing of the past.
 
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ghost_leader07

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UAE
It is a direct swap
So just plug and play no tuning required? I'm asking this because if I'm going thermal i'd have to count for buying a OEM part plus sending my PCM for tuning which can overload my budget a little, i was thinking of going thermal and doing the tuning later on but i guess that's not how it works?

However, I suggest using http://www.lime-swap.com/ instead. Cheaper and @limequat knows his stuff with this engine and can basically do the same as PCMofNC.
I've read a lot about Jeremy of lime-swap seems to have a great reputation among the GM community I'll definitely check them once i decide to go with either ACDelco EV or thermal clutch.
 

mrrsm

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Most of the "Post Shut Down Bubbling" comes from an "Engine Heat Soak" of the the Residual Thermal Load left inside of the Metal Motor that cannot be removed by the constant Flow of Coolant through the Radiator via the Electro-Viscous Clutch Fan releasing that Engine Heat steadily out into the Atmosphere, once the Engine is switched "OFF".

So the Heat involved ALWAYS follows these 'Laws of Thermodynamics' and moves FROM the Hot Engine Metal Parts TO the now Static Coolant and thus, its Temperature will ALWAYS Rise... just after Shutting Down The Motor:

laws-of-thermodynamics-l-2195163478.jpeg
 
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ghost_leader07

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You can go to .... https://tis2web.service.gm.com/tis2web/ there you can input your VIN# and it will list all the available updates for any GM software.

The problem with getting an "original" GM clutch fan is they were not made by GM or AC Delco . They were made by BEHR company. Unfortunately BEHR was bought out recently by MAHLE/Clevite and its my belief after having purchased the "new" BEHR that they are BEHR in name only. They appear to be identical to a $69 knockoff fan i bought off EBAY awhile back that wouldnt work straight out the box.
Cking the recent reviews of the fans sold by GM on the Amazon website it appears GM agrees with me also as they are shipping the HAYDEN brand which some people have had success with.

What IMO is the problem with the replacement fans is on most vehicles the fan pretty much runs at 2 or 3 speeds and the cooling system can cover for variations in the speeds. Envoys cooling systems are the bare minimum required to do the job, the fan speed is almost constantly being changed by the computer and these fans response times to these changes are just to slow. Due to lack of space the Envoy radiator is a single row that just isnt efficient enough to cover for the fan not pulling hard enough. That is why the major complaints GM received when producing these models was how loud the fans were. It was a constant problem that was somewhat but not totally solved by the non-electric "thermal " clutches.

I am not totally convinced that using the Hayden or switching to the thermal clutch will solve the problems for owners like myself who live in 90+ degree climates for 5-6 months out the year. I deal with overheating issues ANY time I drive my car when its over 90 degs outside. And close to 100 forget it, I cant go 10 miles from my house. Ive done and tried everything BUT the software update only because I dont trust any of the area dealerships to do it and I cant find any independent shops who have access to the GM software. I know of 1 that does but its run by a guy who is hard to deal with and I just havent begged them hard enough to do it for me yet.

Its looking more and more like we are going to have to find an upgrade to the radiator somehow someway as getting a reliable fan clutch may be a thing of the past.
Thanks for sharing your experience, but i feel like my truck is destined to be doomed based on what you're saying lol

Surly there's a decent clutch that gets the job done despite their design flaw, since everyone is leaning towards going with thermal clutch i guess it's the way to go.
 

ghost_leader07

Original poster
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Dec 18, 2019
152
UAE
Most of the "Post Shut Down Bubbling" comes from an "Engine Heat Soak" of the the Residual Thermal Load left inside of the Metal Motor that cannot be removed by the constant Flow of Coolant through the Radiator via the Electro-Viscous Clutch releasing that Engine Heat steadily out into the Atmosphere once the Engine is switched "OFF".

So the Heat involved ALWAYS follows these 'Laws of Thermodynamics' and moves FROM the Hot Engine Metal Parts TO the now Static Coolant and thus, its Temperature will ALWAYS Rise... just after Shutting Down The Motor:

View attachment 105026
Thanks for the explanation! So what i gathered is it's a normal characteristics of thermodynamics?
 
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mrrsm

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Yup... From the "Big Bang" to the Very End of Time... ALL Energy Transfers (Conduction, Convection and Radiation) will ALWAYS follow the Three Laws of Thermodynamics.
 
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ghost_leader07

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You can go to .... https://tis2web.service.gm.com/tis2web/ there you can input your VIN# and it will list all the available updates for any GM software.
Just checked the website and got a list of updates seems to be a few but some are generic and hard to understand what issues they address. you can check the list yourself in the attachment.
 

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mrrsm

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Download and Save THIS TECH2paths PDF to give you some additional assistance with the "Button Pressing Sequences" for using your "GYMKO" Tech 2 Scan Tool.

It is organized by Topic or Component in a Logical and , Alphabetical manner and provides a Whole Lotta Good Stuff for any Tech 2 Owners trying to figure out each "Step By Step". :>)
 

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ghost_leader07

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Download and Save THIS TECH2paths PDF to give you some additional assistance with the "Button Pressing Sequences" for using your "GYMKO" Tech 2 Scan Tool.

It is organized by Topic or Component in a Logical and , Alphabetical manner and provides a Whole Lotta Good Stuff for any Tech 2 Owners trying to figure out each "Step By Step". :>)
Thanks but unfortunately I don't have an access to Tech 2 Scan Tool. I'll be sending my PCM by mail for a tune/update, i was just checking the update list to see if there's one addressing the issue i'm having.
 

mrrsm

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Damned Shame.. Really... You've obviously "Got The Chops" that would Make The MOST out of having such a Powerful Device 'In Hand'.
 
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ghost_leader07

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Damned Shame.. Really... You've obviously "Got The Chops" that would Make The MOST out of having such a Powerful Device 'In Hand'.
Yeah well i did explore my options regarding the Tech 2 Scan Tool but i found it extremely expensive for DIY home use (used genuine GM equipment on eBay for +$1600) however i did find Tech 2 clone on AliExpress for less cheaper but I'm not sure if it'll perform the same as the original.
 

Mooseman

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Dec 4, 2011
25,262
Ottawa, ON
So just plug and play no tuning required?
It will need tuning to turn off the error codes for the missing EV clutch (replaced by a thermal clutch). The truck will still work and be unaffected however the CEL will be on. If you have regular emissions testing, it may fail because of it. If not, no worries, you'll know what the light is on for and you'll just need to rescan it once in a while to be sure a new unrelated code hasn't popped up.

However the tuning will also give you some performance and transmission benefits. Nothing earth shattering but it does make some small improvements.

So if you want, get the thermal and wait until your finances allow you to get the tune.
 
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ghost_leader07

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It will need tuning to turn off the error codes for the missing EV clutch (replaced by a thermal clutch). The truck will still work and be unaffected however the CEL will be on. If you have regular emissions testing, it may fail because of it. If not, no worries, you'll know what the light is on for and you'll just need to rescan it once in a while to be sure a new unrelated code hasn't popped up.
Great! I can work with that. I'm ok with CEL until tuning the EV out.

However the tuning will also give you some performance and transmission benefits. Nothing earth shattering but it does make some small improvements.
That's exactly what I'm looking for gaining some extra power and better fuel mileage.

So if you want, get the thermal and wait until your finances allow you to get the tune.
Alright! now when it comes to buying the thermal clutch what are the recommendation? What year/brand?
 

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