Replaced my thermostat last weekend (with pics) - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum



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Go Back   Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum > 2002 - 2009 TrailBlazer/Envoy Tech > 02-09 Vortec 4.2L I-6 Engine and Drivetrain > OEM Issues

OEM Issues Original Equipment Repairs and/or Problems

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  #1  
Old 05-21-2011, 01:02 AM
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mrbflat mrbflat is offline
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Replaced my thermostat last weekend (with pics)

Well, after popping a code P0128 a few weeks back, I found the instructions and inspiration to change my thermostat myself last weekend. BIG SHOUT OUTs to :

Double D --- http://forums.trailvoy.com/showthrea...ght=thermostat

and rbarrio -- http://forums.trailvoy.com/showthrea...ght=thermostat

Both methods were helpful, and once again, this site proves to be invaluable in the money saved on repairs, and the increased life of my TB!

I gathered all my tools as well as the new thermostat, 1 gallon of dexcool, 1 gallon of distilled water, and a new serpentine belt (to replace the original!!)



1 - My first step with all repairs is to disconnect the battery. I like to tie my negative cable back, just to make sure it does not contact anything while I am flopping around under the hood.



2 - Remove the serpentine belt. I used a breaker bar with a long pipe over the handle. It gave me plenty of leverage, and it was easy as pie to push it with one hand, while pulling the belt off with the other.





3 - HELPFUL TIP to remove the alternator, I first removed the bracket, and then removed the two top alternator bolts. THEN, since I was working alone, I grabbed a tie down strap I had laying around, and wrapped it around the A/C hose that snakes in front of the bottom alternator bolt, and then fished the ends of the strap down through the left front wheel well. I pulled my battery, and used that to pull the strap just enough to keep the hose out of the way. From there, I could easily get to the bottom bolt. See pics!!











4 - Disconnect the wires from the back of the alternator, and then slide it/maneuver it to either pull it out, or in my case, move it enough to gain access to the thermostat, which should now be completely visible.



5 - at this point, it was easier for me to remove the thermostat while still connected to the hose. I removed the top bolt from above, and removed the bottom bolt through the wheelwell.





Be prepared for coolant to spill all over once you loosen and remove the t-stat. From here, I found it easier to turn the hose so I could remove the clamp and the old t-stat. Here is the old one... WIDE OPEN, just as expected!!



Old vs. new part. MADE IN CHINA.. on my Chevy!



Putting everything back together was too not hard, but like everyone else, I dropped the bottom bolt when putting the new thermostat on. I finally figured out I could wiggle my hand in there and start the bolt by hand, then go through the wheel well again to tighten it.



Here is the new serp belt. Make sure you get the right one. I have an EXT, and this one went on easily.



And here is my result! After a coolant drain and refill - No more SES light, and all the gauges look good... except the fuel gauge! haha.



I do hope this was as helpful to someone as the posts that inspired me to do this job MYSELF!! Now get out there and don't come back without some scrapped knuckles!
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  #2  
Old 05-21-2011, 03:51 AM
808trailblazer 808trailblazer is offline
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Very nice!
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Old 05-21-2011, 08:06 AM
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Great pics! I'm doing this tonight!
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Old 05-21-2011, 09:57 AM
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Congrats on a job well done....
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Old 05-21-2011, 11:17 AM
Loverotties Loverotties is online now
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Nice job,but I would change the censor (over top of stat) at the same time.It's cheap and you'ld hate to rip it all apart if that was /or part of the problem.
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Old 05-22-2011, 09:09 AM
Wex Wex is offline
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I tucked in old rags where a thermostat bolt could land. saved me lots off time because I dropped a bolt at least six times.

Also, next time I have to go back in there. I am going to double clamp where the hose slides onto the thermostat.

Good idea on tying back the battery cable. Somehow mine wandered back and was making full contact once again. I thought pushing it way back was enough but nope. One could also probably just throw a heavy cloth over it if you have nothing to tie it back with.
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Old 05-23-2011, 01:11 PM
Skoffer Skoffer is offline
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This writup should be stickied. It is clearer and easier to follow than the others on the site.

I wish it would have been here a month ago when I changed the Tstat on my Envoy. It took me 6 hours and All of my cuts/scrapes/bruises have just recently healed.
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Old 05-24-2011, 08:42 PM
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Quote:
Originally Posted by Skoffer View Post
This writup should be stickied. It is clearer and easier to follow than the others on the site.

I wish it would have been here a month ago when I changed the Tstat on my Envoy. It took me 6 hours and All of my cuts/scrapes/bruises have just recently healed.
Sticky please, awesome tips, excellent pictures, and extremely clear write up. I just changed my thermostat at the stealership today. Scary price, guys, compared to buying my own thermostat. Didn't want to tackle the problem myself since I have 4WD and I heard its a lot harder to get the bottom bolt with the drive train in the way. But when it comes time for another new thermostat I will definitely try to do it myself. Thanks O.P.
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Old 05-25-2011, 09:30 PM
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Yes, nice write-up...I have to tackle mine soon as well.
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Old 05-26-2011, 02:55 PM
muskamoot muskamoot is offline
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Thermostst replace

Good write up.Basically the same procedure I followed. I encountered a problem with the center dash vents not working after I disconnected the battery. I had to replace a cooked actuator. Apparently related to the battery disconnect. I'm wondering if placing the hvac controls in the off position and removing the hvac fuses prior to disconnecting the battery may have prevented the actuator problem. Any thoughts on that from any experts out there?
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