Hi Guys,
I was driving down the freeway yesterday, nothing out of the ordinary, and my 'Service Engine Soon' light came on. I bought a code reader and I'm getting P0128. It said in the book something about the thermostat, I read it could be sticking open, as the car is running not much above 160*. Is this likely the case or could something else be the problem?

Are there any writeups on replacing a t-stat on a 3.1? I've only seen one for the 3.8. I see on the 3.8 it looks a lot easier, I think I may have to remove my throttle body to get to the t-stat housing?

Should I be worried about driving it a little over 100 miles at most this week for work?

Thanks guys!

Sounds like the thermostat is stuck open, and yes, it's easier to replace if you remove the throttle body first: Thermostat Location Be sure to get a new throttle body gasket . Here's a link to a repair guide: Thermostat Removal & Installation Hope that helps!

So, replaced the T-Stat and I don't think it fixed the problem. The fans still came on right when we started it up afterwards and I don't think they shoulda been. I haven't cleared the code and watched for it to come back yet, I'll do that tomorrow.

Also: While working on it, my buddy noticed something else wrong: I don't remember exactly but I think it was the CV boot or something CV on the passenger side. It's not too bad yet as it doesn't click when the wheel is cranked all the way but I'd like to take care of it...Any idea how difficult this is to do at home or how expensive it is at a shop? I know my description isn't too good but maybe someone knows..

Thanks guys!

Sorry about the bad CV description, I was tired last night. The only thing I can see is a bunch of grease that has come out of the CV Boot I guess you'd call it. He saw all that and said I need to replace something...now this has got me pretty worried. This a pretty costly fix?

can be. Check to make sure there are no rips, tears, or cuts. Should that not be the fault, check the seals and clamps. If those had shifted, you would throw excess grease everywhere.

Costly? Possibly. If they hafta pull the shaft to replace the boot and grease, yep. Just to adjust the clamps and seals and then re-pack? Not really. I would expect somewhere in the area of 100 USD to 600 USD.

So I talked to the buddy again and it's the CV boot I need. I'll check over the boot, seals, and clamps. I've seen boots with a cut down one side so you can put them on without having to pull everything apart, are these any good if I do need to replace the boot?

Is the 100-600 what it'd cost at a shop? Is that for just the boot?

Thanks!

Back to the original thread topic for a minute: I cleared the code this morning, and it got nice and warm on the way to work. I've driven it probably 40 miles and the light hasn't come back on, and the fans aren't on when they shouldn't be, so I'm thinking its all good.

If the heater blows very hot air, normally your T-stat is good. If the code comes back, it is probably your temp sensor.

As for the CV boot, you best bet is to change the halfshaft. They are $70-$100 at most parts stores. Don't buy the cheap ones.

They are $100 at w-bodystore.
http://www.wbodystore.com/grandprix/halfshafts-new-p-130.html

$85 at ZZP
http://www.zzperformance.com/grand_prix/products1.php?id=596&catid=105