How to replace a thermostat in a Chevy Colorado

In this 10 minute video we take a look at the process of replacing a thermostat in a 1st generation 2007 Chevy Colorado with the I5 3.7 engine. The thermostat is mounted on the driver's side of the engine below the intake and behind the alternator, so can be a bit tricky to reach. My current thermostat was around 10 years old and starting to fail (truck wasn't getting warm enough and was not reaching operating temperature). The new one fixed my problem before I got a check engine light (which I've gotten in the past). Winter is coming, wanted to get this done and have my heat working well before the cold sets in.
This process should be applicable to other 1st generation Colorado, GMC Canyon, Hummer H3, and the Isuzu variants with the I5 engine. I show as much of the process as I could, it was tricky getting a camera in there. If I redo this again in the future maybe I'll try making a recording with my borescope. 😆 If you have any questions, feel free to ask them in the comments. If this video was helpful please 'like' and 'subscribe' to my channel. I do a lot of different types of repair videos and it really helps me out a lot. Thanks!

[@CompTechMike]

If you liked this video or found it helpful, please "like" and "subscribe" to my channel. It really helps me out a lot. I have dozens of videos on troubleshooting and repairs of 1st generation Chevy Colorado and regularly add more. Check out the entire playlist here: kzbin.info/aero/PLZsiP8a81zDFWVAWL_RxIkDSn2TSAcU8y My current truck has 237,000 miles and is still running great. Hope to keep it that way a lot longer. Thanks!

[@techjdu]

I figured I'd put this in your pinned comment for anyone like me who needed the torque specs. It is 89 in/lbs for the thermostat, and 100 ft/lbs for the wheel lugs.

[@chazatkinson]

Genius engineering putting the thermostat in such a easily accessible location!

[@CompTechMike]

Ha! Your comment made me LOL. A terrible location to be sure. 😆

[@richardmiller4817]

Do you think Chevy could have created a more difficult place? Makes me love my ford even more

[@CompTechMike]

Ha! I know. Terrible location. Even worse for people who have the coil springs suspension in the front (at least mine has torsion bars, which have a little more room to reach around). Makes me miss my old big block V8 cars. Enough room to climb under the hood and sit on the engine and thermostat right on the top-front, where god intended it to be. 😄

[@thangknowa3288]

Pretty much same for coil spring models like my '05 Z71 I-5 Colorado. Bit of a beech, but not a big, bad , nasty beech. I changed top hose, and rad cap at the same time, as well as washed out the reservoir tank and refilled with coolant. I like 100% Peak Antifreeze that I mix 50/50 with distilled water.

[@CompTechMike]

Thanks for the tips! I know clearance can be a bit tighter on vehicles with coil springs, as opposed to torsion bars (like mine). Glad you were able to get it without too much difficulty. 😊

[@julianoliva2850]

I recently upgraded to an aluminum 2rows crossflow radiator + a derale 16” tornado puller efan but want to change the thermostat to lower the temp… right now the sensor temp is 195-180 I have friends that built off-road race trucks and told me to drill 3-4 small holes to lower the coolant temp and engine heat so that’s what I’m planning to do… the engine is a 4 cylinder saludos desde ensenada México

[@CompTechMike]

Hi again Julian! The original 1st generation Colorado/Canyon thermostats typically ran 180°. A few years into production that was changed to 195°. All original 180° parts have been discontinued and are extremely hard to find. I've had no trouble using a 195° thermostat in my vehicle. Checking with a code scanner shows the vehicle operates right at about that temperature, or slightly warmer during summer / AC on / or when towing. This usually corresponds to right about the middle mark on the temperature gauge on the dashboard, but those gauges are notoriously inaccurate and can vary widely from one vehicle to the next. Best to use a scanner. Drilling a few small holes can lower the temp, but can I ask why you want to do this? It will most likely have a negative impact on gas mileage, compared to running the recommended temp thermostat. My recommendation would be to use the stock rated part from a reputable seller like RockAuto.com and not drill the holes, unless you're running in an extreme temperature environment. Good luck!

[@someoldguy109]

I have a 2004 colorado z71. I'm going to try to learn from you so I can work on my own truck.

[@CompTechMike]

Fantastic! Best of luck to you. They're great trucks, just gotta take care of 'em. Many on the road still with 200,000+ miles on them.

[@someoldguy109]

@@CompTechMike My truck has 220,000 miles.

[@mrkttrdr2919]

Great job, been following ur vids over the years, very well produced, not surprising u still got ur coly, I’m holding on to my 05 rust bucket, luv mine, about to do both front wheel bearings and the vvt solenoid u changed out a while back, thanks for posting

[@CompTechMike]

Hi! Thank you so much for the kind words. My 07 has just under 236,000 miles on it now. I really do enjoy the truck and am doing my best to keep her running a few more years, and am glad my videos have helped others. Good luck with those wheel bearings! Do you have 4WD? Those can be pretty challenging.

[@mrkttrdr2919]

@@CompTechMike no, have 2wd, the ls sport pkg, got 177,000 on the clock, getting to the point of dimminishing returns , engine runs great, we'll see how long it'll hold on

[@CompTechMike]

@@mrkttrdr2919 I hear that. Thinking about spending a couple thousand dollars on suspension and electrical work here, in the near future. It's a tough choice - I love the truck, but would I be better served putting that money towards a newer one? Best of luck with yours.

[@michael.morrow]

When you use the Permatex for the O-ring, are you literally just using a dab or two or should I make a line of it around the entire ring?

[@CompTechMike]

Hi Michael! Thanks for checking out my Colorado repair videos. Sorry if I did not explain this more clearly. The O-ring is held in place by "sandwiching it" between the side of the motor and the thermostat housing. To keep it from falling out while reaching in there during assembly, I use just a few tiny dabs of a water pump & thermostat-safe gasket maker (such as Permatex Blue). A few similar products have been suggested in other comments. The idea is to just keep the O-ring from slipping out of its groove during assembly. Good luck, hope this helps!

[@310panda]

Thanks this video save me. i see other videos. You are one of the best explained.

[@CompTechMike]

You're welcome! Glad to help. 🙂

[@CompTechMike]

In this 10 minute video we take a look at the process of replacing a thermostat in a 1st generation 2007 Chevy Colorado with the I5 3.7 engine. The thermostat is mounted on the driver's side of the engine below the intake and behind the alternator, so can be a bit tricky to reach. My current thermostat was around 10 years old and starting to fail (truck wasn't getting warm enough and was not reaching operating temperature). The new one fixed my problem before I got a check engine light (which I've gotten in the past). Winter is coming, wanted to get this done and have my heat working well before the cold sets in. This process should be applicable to other 1st generation Colorado, GMC Canyon, Hummer H3, and the Isuzu variants with the I5 engine. I show as much of the process as I could, it was tricky getting a camera in there. If I redo this again in the future maybe I'll try making a recording with my borescope. 😆 If you have any questions, feel free to ask them in the comments. If this video was helpful please 'like' and 'subscribe' to my channel. I do a lot of different types of repair videos and it really helps me out a lot. Thanks!

[@mikeb5607]

What did you use to hold the o-ring in place on the thermostat? I just bought a new ACDelco oem replacement and realized the o-ring just lays in the groove and is not a (finger) press fit to help keep it in place during installation.

[@CompTechMike]

​@@mikeb5607Hi! Great question. I used a small amount of Permatex gasket maker in the groove to hold the O-ring in place while assembling it. Thanks for asking! 😊

[@mikeb5607]

@@CompTechMike Thanks ... I was thinking of using a little sil-glyde grease because that shouldn't be harmful to a rubber o-ring. Kind of ridiculous that the groove isn't tight enough to hold the o-ring in place by itself. I looked at a Moto-Rad at a parts store out of curiosity and the groove was tight enough to hold the o-ring in by itself. AC/Delco - Nope!! I just want to be careful of what product I am using with an o-ring because they are intended to be installed basically dry. Anyway ... nice video you did. Thanks Mike

[@CompTechMike]

@@mikeb5607 awesome! I've never heard of Moto-Rad before but will have to look into that brand for the future. I'm pretty old and still remember the "Keep your GM all GM" stickers on my old cars from the 1960's and '70s, and have always tried to use "GM Genuine" or "AC Delco" parts, even if they're probably all made overseas these days. Sounds like other aftermarket parts may be equally good (or even better) now. Glad the video was helpful, let us know how it works out with the Sil-Glyde.

[@tailypoe]

Thanks for the video. Can you tell me what tool you're using to remove the inner fender clips? I've never met a plastic clip I didn't break, so it'd be nice to know how to not end up mangling these. Great content man, thanks again!

[@CompTechMike]

Hi there! Thanks for checking out my video. If you pause it a few times starting around the 5:00 minute mark you can see I'm just using a regular Leatherman multitool to remove the clips around the inner fender liner. The clips on these trucks are pretty durable, I've removed them a few times and rarely break them. I'm sure GM has a specialized tool but my "go to" for anything like this is usually just my Leatherman. It helps that I've got a bucket full of spares of different sizes though, if one does break. 😆 Good luck to you!

[@tailypoe]

Thanks, I ended up using a trim-button popper that I forgot I had lying around. Plus that same AC Delco thermostat that I bought like 5 years ago to do this repair 😵‍💫. Successful install thanks to you - nice to finally have my truck warmed up to normal operating temperature 😅

[@CompTechMike]

@@tailypoe glad to hear you got it! And good idea on the trim tool. 😊

[@saltyboystan4096]

Hey great video. Gotta change mine soon. Also where did you get your brush guard from? I want to get one for my 05 Colorado. And do you think they have em in chrome? I’m also a new subscriber. Glad I stumbled onto your content.

[@CompTechMike]

Hi Stan! Thanks for checking out my videos. Glad they're helpful to you. 😊 The brush guard is commonly referred to as a "Hunter" or "Truck Gear Direct" brush guard. Ever since being in a few accidents with deer I put them on all my trucks. I've got an install video on KZbin, and in the video description are some links for ordering. Price has gone up a bit since I got mine way back in the day, but they should have it in both black and chrome. You can check it out here: kzbin.info/www/bejne/iaXZiWuLib6gaLc Thanks!

[@saltyboystan4096]

Thank you so much. Will definitely give them a heads up.

[@th3kings983]

Hi. Just wondering since you replaced your thermostat what is your current temperatures with this new GM one ? I replaced mine on my Colorado with a stant ? And now it's 1/2 to almost 3/4. I'm replacing it again with a GM one next week. But looking online other trucks now run hot

[@CompTechMike]

Hi Rogelio! Thanks for watching and commenting on my video. You can see in my photo at the very end of the video that the temperature needle is sitting exactly at the middle mark, and a scan tool hooked up shows that the engine coolant temp is 196 degrees F. This is exactly where it should be. Prior to replacing it it was stuck open / running too cold, which can effect fuel economy. You can see the photo at the very end of the video. Here is a link to the timestamp: kzbin.info/www/bejne/nZ-2oHaZnpV9iNE That said, I do not recommend trusting just the so-called "idiot gauge". Recommend always plugging in a scan tool to see your exact temp. If it is not correct, a common symptom is the thermostat or the temperature sending unit. Also occasionally the gauge on the dashboard has been known to fail. So your first step would be to plug in a scan tool to measure your actual temp (rather than just looking at the gauge). Ideally it should be right around 195. It may be hotter in the summer if you have the AC running, or are towing or driving up steep hills. But definitely want to check it out if it's sitting at 3/4 mark all the time. Start with a coolant flush, replacement thermostat, inspect hoses, and temp sending unit. Good luck!

[@th3kings983]

Thank you for all the info. Keep up the good work.

[@Aliwayz214]

Great job thank you very much 👍

[@CompTechMike]

You're welcome! Glad to help. 😊

[@randumdude5824]

Thankyou for this video, by any chance did your dash say. “ ac off”. I get the “ ac off alert on dash and the temp guage doesn’t register any temp at all. When obd 2 scan says it’s a po128 code. It corrects itself the next day after driving 5 or ten minutes.

[@CompTechMike]

Hi Random Dude! Funny screen name. 😆 Mine did not give the "AC Off" message either of the two times my thermostat failed (in 2012 and 2022), but I know that is a common symptom of the thermostat being bad. If the truck is unable to reach operating temperature it will preemptively disable the AC. So yes, according to many forum posts, this is a common side effect of the thermostat being bad. Replacing the thermostat should fix your problem. If you still have trouble after that, I'd look at the temperature sensor (the piece that measures the actual temperature and is responsible for sending that info to the vehicle computer and dash). Good luck, let me know how it goes!

[@randumdude5824]

@@CompTechMike thanks. I’ll let you know

[@techjdu]

@@randumdude5824 My mom's is doing the same as yours, did this fix it?

[@randumdude5824]

@@techjduyes it fixed it. I changed the thermostat knowing that if that didn’t fix it it may be a coolant temperature sensor, I have a 2wd I didn’t have to remove the inner fender I just popped off the nearest clips and bent the plastic out of the way. Job took 45 min ,it was the first time ever changing a thermostat. Tip. A little bit of tape will help you get the bolts back in easier. It’s tight in there. I also change the lower hose it had a wear spot. And some cracks. I also did a coolant flush that is not included in the 45 minutes. Remove the hose. And the thermostat together it makes it easier when lining up the new one , don’t waste time trying to put the hose on after installing the thermostat. Torque to spec. Good luck.

[@randumdude5824]

@@techjdu i read some were that thermostats have a lifespan 100k or ten years. Mine is an 08 With 40k miles. That why I why I decided to change the thermostat rather than the coolant temp sensor

[@dannyrosario3781]

Engineers don't care what mechanics have to work with(HAVE A FEW ENGINEERS FRIENDS) as long as they can squeeze more parts in.

[@CompTechMike]

True, haha. 😆

[@maxellison55]

Well presented.

[@CompTechMike]

Thanks! 😊

[@julianoliva2850]

Why cars designers don’t think to put interchangeable parts that need maintenance in easy places to be tuned up that makes things complicated to us and mechanics I own a 2011 chevy Colorado 2.9 AT with a lot of upgrades and swaps for a callejero race truck saludos desde ensenada México 🍀🌹🎶🍻🤘🏽😉

[@CompTechMike]

Hi Julian! Yes, I agree completely. Routine wear & maintenance components should always be easily accessible. Just like every fluid should have an easily accessible drain plug and fill hole. It's almost like engineers never worked on cars in their lives! 😆

[@chaparroreyesreyes7099]

Thanks. It’s good video 👍

[@CompTechMike]

You're welcome! Glad to help. 😊

[@abehamm6685]

That is great 👍 👌 very good thanks

[@CompTechMike]

You're welcome! Glad to help. 😊

[@MrBoomify]

Would you put some sealant on the rubber seal, cause ive developed a very leak when I put everything back together. I tried to wrench it down more and ended up breaking to head off one the bolts and had to fish out he broken bolt and replace the bolt. Was able to use my finger to get it out. Ive torqued it to speck 89inch pound and still have a very small leak. That I didnt have before. Thinking about exchanging the thermostat I bought.

[@CompTechMike]

Hi! Thanks for the comment. I think I mentioned in the video (but did not show) that I used a thin amount of Permatex around the rubber O ring to hold it in the groove while tightening. It's hard to get everything lined up and have it stay seated, maybe give this a shot? I'd also exchange your thermostat. Possibly it's warped. Good luck!

[@MrBoomify]

@@CompTechMike I'll try that later and let you know

[@levijoeable]

Good job

[@CompTechMike]

Thanks Levi! Glad to help. 😊

[@timshaw157]

Does this thermostat not get a gasket

[@CompTechMike]

Hi Tim! It uses a rubber O-ring that fits in a groove in the housing. You can see it at 1:45 mark in the video.

[@timshaw157]

@@CompTechMike Okay just wanna be sure,Thank You

[@RainsMobileMechanic]

Hey thanks for the vid just got the p0128 code and literally tells me coolant thermostat😂 so i have to change it assuming it’s stuck open so I have a question when filling the coolant back up how much do you fill in the radiator cap first before you fill the overfill reservoir? And do you fill the reservoir after starting the engine up to temperature and as the thermostat opens and lets coolant in do you keep adding to the reservoir until when? Thanks 🙏

[@CompTechMike]

Hi Rain! Thanks for watching & commenting on my video. Yes, it's nice when a code points you exactly to the problem. 😊 For refilling, personally what I do is use the pre-mixed 50/50 stuff so that I don't have to worry about mixing. Fill the radiator all the way to the top, and the overflow jug to the 'full' level marker on the side. Start the engine with the radiator cap off and run it for 5-10 minutes with the heat on, until it reaches operating temperature, periodically squeezing the radiator hose to make sure no air gets trapped in there (be careful - hot!). This process is to circulate the coolant and release any trapped air, commonly called "burping" the system. Refill radiator as-needed, and close cap tightly. Drive normally for a day or two and re-check levels in the radiator and overflow jug (always make sure engine is cool when removing cap). You may hear noises in the dashboard (from the heater core located on the passenger side) if you have air trapped in the system. Ensure that the temperature is correct with the dashboard gauge or with a scan tool connected that can read the engine temperature. Hope this helps!

[@RainsMobileMechanic]

@@CompTechMike alrighty thanks!!!! It does help also in a future video it would be nice to see the jacking and jack stand point for this truck!! Will be using your vids for my 2005 for years to come

[@CompTechMike]

@@RainsMobileMechanic hi! Thanks for the suggestion! You can kind of see that around the 4:32 minute mark in the video. I sped the clip up because it's not very interesting, LOL. 😆 I use an old Craftsman floor jack and jackstands, nothing special. Colorado has a regular body-on-frame truck construction (as opposed to most cars, which are typically unibody). With the full frame you can basically jack it up from anywhere underneath, as long as it's not too rusty. 😉 My 07 just rolled over 238,000 miles a few days ago and is still running great. Hopefully yours will continue to run well for many years, as well.

[@RainsMobileMechanic]

@@CompTechMike sweet!! Also I just changed my thermostat no leaks at the lower radiator hose or thermostat just wondering what your normal operating temp is mine car runs from 199-207 degrees is this normal ?? It’s winter now where I’m at temps are 30s -40s

[@CompTechMike]

@@RainsMobileMechanic the thermostat should regulate temperature to around 195 degrees. A few degrees hotter if the weather is hot / AC is running, or if towing or driving uphill, is normal. However I wouldn't expect it to be 207 if it's being driven normally and the temperatures outside are 30s-40s. That sounds high to me. Are you checking that with a scan tool or just looking at the gauge on the dashboard?

[@someoldguy109]

Thank you.

[@CompTechMike]

You're welcome! Glad to help. 😊

[@josecavada3830]

👍

[@michaelbaskinmichael9862]

Could it cause it to use more feul

[@CompTechMike]

Hi Michael, thanks for checking out our Chevy Colorado repair videos! I'm not entirely sure I understand the question. Are you asking if a bad thermostat could cause the vehicle to use more fuel? If so, yes, that is correct. A thermostat that is opening too quickly will cause the vehicle to not be able to reach its optimal operating temperature, in which case fuel efficiency would be worse. Normally you will also get a check engine light, if this is the case. You can also check operating temperature with a scan tool hooked to the OBD port. A correctly running Chevy Colorado should normally operate around 190-200 degrees, or a little bit more in hot months or if towing. Hope this helps!

[@michaelbaskinmichael9862]

Wow idk that I was totally surprised at that,today I replaced the thermostat and new coolant . So we hope all is better now thanks for reaching out thanks

[@CompTechMike]

​@@michaelbaskinmichael9862good luck, hope it helps!

[@futuregamer5791]

Let me guess... They make you purchase more than just the actual thermostat?

[@CompTechMike]

Hi! Thanks for checking out my Colorado repair videos. I'm not sure I understand your question. Who is "they"? Of course you can purchase just the replacement thermostat, if you choose. Many retail automotive stores have them in stock as do dealers, online, Amazon, Rockauto, etc. Of course my recommendation if you're replacing the thermostat in this vehicle is to also replace the lower radiator hose and clamps. Since they need to come off anyway and at this point are probably 15+ years old, why not replace them with new? They're cheap enough. Just my 02 cents. Safe travels!

[@michaelbaskinmichael9862]

I think you should just change it instead of all that blah

[@CompTechMike]

I'm explaining how to do it. You obviously don't know how, or you wouldn't have come here. 🤷 But feel free to make your own video if you think you can do better. 😆

[@michaelbaskinmichael9862]

I'm sorry you didn't like my response but no disrespect I just thought you rambled on a little Tom much ,sorry dude.

[@michaelbaskinmichael9862]

I can do better if that's a bet

[@michaelbaskinmichael9862]

I came here because I haven't done a Colorado before and wanted to see if any of it was a problem to do it's all a easy job no problem at all I finished in record time

[@CompTechMike]

​​​@@michaelbaskinmichael9862I'm explaining the tools needed, part numbers, and the process. A lot of people learn that way. If it wasn't helping people then these videos probably wouldn't have over 3M views. 🤷 Point being, a lot of people learn this way. And a lot of videos don't explain the process, or just play annoying music. If you don't have anything helpful to contribute you're free to just keep scrolling instead of leaving rude comments. 🙄