Thermostat replacement time!

[JPaul]

Well, I got the "AC OFF" message earlier this week and my temp guage was registering zero. After some investigation and observation of how my H3's cooling seems to be doing (every now and then it will run much cooler than it should be), I have determined it's time to replace the thermostat and coolant temp sensor (might as well do both at the same time since you lose a fair bit of coolant replacing either one, and my H3 has 76,000+ miles on it).

I ordered this thermostat off of Amazon after deciding I didn't want to mess around with trying to find an OEM 180 degree thermostat:

http://www.amazon.com/gp/product/B0031GRUCG


Got it in today and it turns out to appear to be a good compromise between the 194 degree and 180 degree thermostat. This one is specified at 187F (86C). Good enough for me, especially since I got it in two days with practically no work on my part (yay Prime!).

Now I just have to do all the work of replacing them.

 

[Texatl]

It's no fun. I went at this last weekend. There is hardly a more hateful task. Lots of cussing, throwing stuff, stomping, etc...

for the experts- once the wheel and liner is out, how exactly can one get at the upper t-stat bolt? 2 extensions, a coupling, etc... And I still couldn't get the socket on it. Ugh!!!!

 

[scoreh3]

Yep pretty much a big PITA to take everything off to get to 2 bolts that are around and behind other stuff . I'm a big believer in the fact that a designer should have to work on what they designed before it can be put in to production .

 

[rascole]

Wow, it isn't that big of a deal. Took me longer to pull the hose off then take the thermostat out. Once the liner is out, take the clamp off with extended pliers or needle nose pliers. The upper/hidden bolt needs a U joint adapter and a 12" extension. Very easy. The hardest part is putting it back in, BUT if you use some painters tape to hold it in it works fine. Replace the hose and clamps while you're at it.

 

[Texatl]

Well I had 2 six inch extensions and a u joint. Couldn't get on the top one and certainly didn't see how to get it back on. LOL I was thinking tape, but.... Big F-U GM!!! Thanks for making a basic tasks on most cars so damn hard.

its been my only beef with GM, each of their cars has "something" that is normal and easy elsewhere that they make idiotic. If they just lowered the battery tray, I could have taken that out and got the top one from the top. But noooooo I should pay the dealer ungodly money to change a part I can change on every other f-ing car I've ever owned.

yeah rascole- for me it's kinda a big deal. I expect to be able to perform basic maintenance myself, when that is harder than normal and take longer than expected... It's kinda a big deal. Seriously, this is something like I have never seen before. And I do a lot of my own work on cars/trucks.

 

[rascole]

Did you take the hose off first? With the hose out of the way it was easier to get to the bolt. I did replace the clamps with worm drive because one of the spring clamps broke.

 

[JPaul]

Well, I got the thermostat replaced. Bit of a pain, but I've dealt with worse. Turns out the old thermostat was opening far too soon. I tested it and it opened up at about 175 degrees instead of 195 like it should have. It was full open by 195-200 degrees. This was causing it to never really get up to proper temperature, and I think there were times it was opening even sooner.

You really do need to take off the hose. I was able to get some channel locks in and get the clamp off, the it took some work.

The trick with getting the hose off is using the right tools. After 7+ years, they like to be pretty stuck. Here is the right tool:

I got it at Harbor freight I think, that or Autozone. It's specifically for removing cooling hoses. It slips in underneath and then you loosen up the hose with it. Then you should be able to pull the hose right off.

After doing that I was able to get the bolts off quite easily. Getting them back on is a little tricky, but the trick to that is to get some sticky grease (I used some dielectric grease) and put it on the bolt head. This will hold the bolt onto the socket enough to be able to get it on fairly easily.

 

[JPaul]

So I double checked the part number again and the old one is the 180 degree thermostat. So I guess it opening at 175 isn't too cool, but it still didn't seem to be letting the engine get to proper operating temperature. Other possibility is the t-stat was fine, but the sensor isn't. Haven't replaced the sensor yet though (didn't feel like driving to get a crows foot for it just to have to wait a couple hours plus for the engine to cool back down enough to work on it without getting burned), so if it keeps having issues then that might be the issue instead.

Either way, the truck has 7+ years and 76,000 miles on it, so it's a realistic time for the t-stat to need to be replaced.

 

[Texatl]

Did you take the hose off first? With the hose out of the way it was easier to get to the bolt. I did replace the clamps with worm drive because one of the spring clamps broke.

Well... No I did not take the upper part of hose after draining the lower. It was one of those, if I get the hose off and cannot get the bolt on/off I'm screwed either way. Point of no return. But maybe hose off first is the way. The how-to on another site had them leaving it on. I think because of the clamp. And yes I got worm clamps as well, screw those other types.

i am willing to stop my tantrum and try again. But it still peeves me that it's that dumb.

 

[rascole]

Grab a six pack of cold ones, take a deep breath, and enjoy the beers. They always make working on the truck better, maybe not easier, but definitely better.

 

[scoreh3]

It wasn't a hard job , just a long job compared to most thermostat R&R . When they designed and built the motor on an engine stand , I bet it was really easy to install .

 

[Texatl]

Grab a six pack of cold ones, take a deep breath, and enjoy the beers. They always make working on the truck better, maybe not easier, but definitely better.

Ok I'll give you that. I was thinking this will be so easy I've done it a bunch of times on other vehicles. This time... :-/ beer was a better idea. I'll use that tool first.

 

[Traxx]

Beer should always be on top of the toolbox before opening any drawers for tools.

 

[alrock]

Reloader and I (mostly Reloader) did mine this weekend. Thermostat was fine, but I was replacing hoses so we went ahead and did the thermostat since it probably has 75,000 miles on it. Definitely an annoying job.

 

[JPaul]

It would have been a lot easier if the body panel right there by the engine had been cut up to where the crimp is in it. Having it stick down so low makes it rather difficult to get your hand in there. My wrists are all scraped up and bruised from wedging in there. And since I didn't bother taking off the wheel my chest is pretty bruised as well from wedging myself in to reach everything (had to while it was turned to the right to get the hose clamp off/on).

But my temps are nice and even now. stays right around the half mark.

 

[rascole]

It would have been a lot easier if the body panel right there by the engine had been cut up to where the crimp is in it. Having it stick down so low makes it rather difficult to get your hand in there. My wrists are all scraped up and bruised from wedging in there. And since I didn't bother taking off the wheel my chest is pretty bruised as well from wedging myself in to reach everything (had to while it was turned to the right to get the hose clamp off/on).

But my temps are nice and even now. stays right around the half mark.

I seriously considered drilling a 1/2" hole to make it a straight shot to the top bolt. But patience was the key.