Chevy Colorado & GMC Canyon banner

Replacing thermostat

45K views 15 replies 9 participants last post by  ice_burg 
#1 ·
Recently I have noticed that my temperature has been fluctuating dramatically and I am hoping that it is a bad thermostat. The gauge is normally just below the 1/2 mark when warmed to normal operating temp. Recently if I hit WOT, the gauge will drop to almost 1/4. I have never noticed this behavior until recently. The other thing that I am hoping it is related to is an issue I have been having of the torque converter not engaging, so my rpms are higher than they should be. Anyway, can anyone tell me where the thermostat is located so I can replace it? I am sure that I can find the correct one, however if someone knows any part numbers, that would be great too.

I appreciate any help that anyone can give. Thanks.
 
#2 ·
Just follow the upper radiator hose to the engine. This engine uses a thermostat that has a built-on housing --- therefore it is more expensive than what you may be used to paying for a thermostat. I believe it is around $20. Good luck!
 
#3 ·
If it drops to 1/4 then rises back up to 1/2 mark, then everything sounds normal. It's been discussed here many times, especially if you live in cold climates (Chicago ?), but I couldn't find any threads thru the search engine. :clueless . The t-stat is located under the intake, behind the alternator. Follow the hose at the bottom of the radiator, drivers side, to the engine block. The A/C part # is 12579956 (4.14.2005).



 
#5 ·
Thanks for the responses and also the pictures. Thats great. I am not sure what would be normal or not. Today was 65 though and after driving for over half and hour to have the temp drop that much seems rather abnormal. I am really just trying to figure out what my torque converter issue is and this being the least expensive option, I thought I would try this first. If there is a problem with the temperature, it seems somewhat logical that it could be influencing the computer temps and possibly not allowing the torque converter to engage. I am really hoping and guessing here. Anyway, thanks again.
 
#7 ·
If it only does it at WOT, the t-stat is probably OK. When you hit WOT, you are circulating the slightly colder coolant rather quickly from the radiator into your engine. This is probably what you are seeing on your temp gauge. I also poked around in HP Tuners - I didn't see where torque converter lockup was temperature related. Other than that, I have absolutely 0 knowledge of auto tranny's.
 
#8 ·
x2 ulmerc

timmyj:

Perhaps a loose connection somewhere....

On my way to Indiana yesterday for an appointment I crested a hill - hopped a little and came down hard....my gauages zeroed and then came back up - but the truck would no longer shift into overdrive....when I came to a stop sign and tried to start out it seemed to start out in 2nd....so no first or OD. I shut the truck off to reset and it did on the third try.... It ran fine the rest of the day... American Chevrolet in Muncie said should be no prob to drive but they did not have anyone to look at it....

Sorry, for the long post. Taking it to local dealer today....

Keep us posted...
 
#9 ·
has anybody found a higher temp t-stat yet, i always run just below a qtr on the gauge an the one time i ran higher (1/2) i got decent mileage, so i think i could get better mileage with a higher one
 
#10 ·
fixitman04 said:
has anybody found a higher temp t-stat yet, i always run just below a qtr on the gauge an the one time i ran higher (1/2) i got decent mileage, so i think i could get better mileage with a higher one
I almost wonder if your thermostat isn't slightly defective and opening at around 160 instead of 180. Maybe try picking one up and replacing it? See if it makes a difference?
 
#11 ·
Just to rule out the battery on my torque converter issue, I had it tested and it was fine - 100%. I do believe there is an issue with the thermostat. It drops considerably at WOT, but it also flucuates way more than I ever noticed during normal driving as well. I called the dealer and they wanted $57 for the thermostat. I ordered it from gmpartsdirect.com for 18 plus shipping. When I get it, I will let everyone know if that helped either problem I am having.
 
#13 ·
Do you have to replace any coolant when replacing our thermostat?
 
#14 ·
I would say whatever leaks out needs to be replaced unless it is old old..like 5 years old. I think our trucks came with the extended life coolant in them.. Someone correct me if I am wrong..
 
#15 ·
I guess what I meant is does this drain the system?

I'll never get to the 5 year mark. I'm about to hit 60k miles this weekend and my 2 year mark is April 26th, 2007.

No worries on it going bad from old age here.
 
#16 ·
No just do it when it is cold. The thermostat is usually mounted on the high side of the motor and very little if any would drain...What is in the hose will drain unless you take steps to pinch it off to stop that from happening. I am with you. My truck is 20 months old with 50k miles on it.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top