[jwh]

2017 Colorado Crew Cab 4WD w/ V6, 100K miles on the clock. Recently there are two things that I suspect are related:

1) The temperature gauge stays at the lowest point in spite of the engine warming up enough that the heater blows hot.
2) The radiator fan comes on and runs for 5-10 minutes after I park when I don't think it should. Like when it's quite cool out and I've only driven a short distance. In the past I only noticed it running when it was very hot out and I had been using the A/C.

I checked the coolant and coolant levels and all look to be normal. Nothing odd about the radiator hoses or heater lines that I can detect. Engine or radiator don't seem to be overly hot (i.e. no coolant spurting into the overflow tank) and everything else seems normal.

Thoughts?

 

[AngryScientist]

faulty coolant temp sensor would be my guess.

these trucks do seem to have a number of issues surrounding the cooling system it seems!

 

[jwh]

Hey thanks! I found a few other postings that indicated the sensor might be the problem.

Question: Where is it and what's its part number?

 

[carloliveira]

Burp the coolant system jack up front of vehicle as high as possible remove reservoir cap while coolant is cold, start engine and keep topping off the reservoir till most air is out of system. Your system may be full of air and has failed to purge the excess air so the coolant temp is reading incorrectly. Post pictures before and after of your coolant reservoir.

 

[RocketJoe777]

I have been having the exact same issue . I usually disconnect the battery then it reads fine . Thats my ******* fix until I have time to dive into it .

 

[jwh]

I have been having the exact same issue . I usually disconnect the battery then it reads fine . Thats my *** fix until I have time to dive into it .

Ok, so that worked. Interesting. Any idea what is the root cause?

 

[Iamscotticus]

check the connections to the sensors. like any other thing that conducts electricity, elements tend to accumulate between two pieces of metal and you get corrosion, rust, etc, that can interfere with voltages. wiggling, reconnecting, cleaning connections solves a lot of issues.

 

[jwh]

check the connections to the sensors. like any other thing that conducts electricity, elements tend to accumulate between two pieces of metal and you get corrosion, rust, etc, that can interfere with voltages. wiggling, reconnecting, cleaning connections solves a lot of issues.

I'll ask it again, where is the coolant temperature sensor? I've looked around on the engine and it's not obvious.

 

[Hunter62]

I googled this issue and seems some are fixed with burbing it, even though they say it was never low on fluid and others by disconnecting the battery for 10 minutes

the sensor is on left side on motor, near rear, mounted to bank 2 cylinder head, near exhaust pipe
they say you need a special wrench to remove and install it and by looking at it I can see why
numerous pictures of it's location on the web

 

[Iamscotticus]

I'll ask it again, where is the coolant temperature sensor? I've looked around on the engine and it's not obvious.

Sorry, Ive never poked around enough to find out. On my other vehicles there are usually 3or4 sensors. radiator top, radiator bottom, thermostat housing and maybe one on the head, or heads. I believe the thermostat is at the lower left (drivers pov) Thar will be an interesting change when its time.

 

[RocketJoe777]

Im going to replace mine this weekend Iif time permits . I will let you know , and take some pictures for you .

 

[Iamscotticus]

Im going to replace mine this weekend Iif time permits . I will let you know , and take some pictures for you .

Thst would be sweet.
Please create a thread with all that in the how-to forum with a title the search engines will hit on like "gen 2 Colorado thermostat replacement "

 

[RocketJoe777]

Hey sorry I did not get to it this weekend . Im still having the issue , its getting to be a pain in the a**.

 

[Edizzle888]

Did you solve it?

 

[jwh]

Did you solve it?

Unfortunately not. It's been several months since this last happened but it started again this week.

 

[Edizzle888]

😰 well I will change the sensor Saturday….maybe? Assuming you haven’t changed yours?

 

[jwh]

😰 well I will change the sensor Saturday….maybe? Assuming you haven’t changed yours?

No I haven't but it's next on my list of things to try. Please let me know how it goes for you. If you can, please post a couple of photos of the operation.

 

[Edizzle888]

No I haven't but it's next on my list of things to try. Please let me know how it goes for you. If you can, please post a couple of photos of the operation.

I unplugged the battery as suggested. (Start easy) all issues seem to be gone. If it comes back I’ll replace the sensor which seems to need a special tool. Thanks GM

 

[jwh]

I finally got tired of dealing with this issue and replaced the coolant temperature sensor. What a PITA! It's located near the front of the engine down between the banks. You really cannot even see it unless you pull off the intake manifold and even then you can't reach it with your hands. On top of that it's angled such that you can't get a socket on it even with a u-joint.

I found that I could get a 15mm box wrench vertically on the flats and turn it with screwdriver on the other end.

That does seem to have resolved the issue though.

 

[Tom S.]

I finally got tired of dealing with this issue and replaced the coolant temperature sensor. What a PITA! It's located near the front of the engine down between the banks. You really cannot even see it unless you pull off the intake manifold and even then you can't reach it with your hands. On top of that it's angled such that you can't get a socket on it even with a u-joint.

I found that I could get a 15mm box wrench vertically on the flats and turn it with screwdriver on the other end.

That does seem to have resolved the issue though.

Thanks for coming back and updating!