tom5170

Checked coolant resevoir and coolant level was low. Ran the truck around the block and the needle went to almost red. Poured some anti freeze in the resevoir and it stayed cooler but still went to red. Thought it was a radiator hose leaking so I replaced the lower hose. After I dumped all the coolant, I only put half a gallon back in. I couldnt figure out why it was running for 2 minutes then going on red. So I put 2 more gallons of coolant down the radiator and it kept it cooled at idle. Ran the truck around for a bit and it still kept cool. Still found it was leaking and it was coming from the water pump so I replaced that. Poured 2 more gallons and filled up the radiator.

Then today, I ran the truck around the neighborhood for about 20 minutes and the temp gauge slowly went to red. Parked it in the driveway, turned it off for 2 minutes. Then started it back up and the needle went back to a little bit before half. The truck will stay cool at idle, but when you drive it around for a bit, the needle will go to red. Is this a thermostat problem or what? Truck has a really good idle and doesnt run rough. it's a 93 silverado with 250,000 miles. The salesman at the dealership told me that the guy traded it in because it was a gas guzzler and he drove it to work 50 miles everyday.

tsduke

Sounds like thermostat to me. I would have replaced it when the coolant was drained since they are cheap anyway.

tom5170

I have one still in the box. I just didnt put it on because I couldnt get the bolt off. And I figured maybe it wasnt that since it was staying cool LOL.

tom5170

Okay so I ran the truck again.

Started it up, kept it running for 10 minutes. The temp needle went up just a little but not alot. The heater was blowing hot but didnt feel hot enough. So I took it for a ride up and down the street and around the block twice. This time the heat was blowing hot. So then I came back, the needle was at the middle, so I went around the block again. Came back and parked it in the driveway. Kept it running for about 10-15 minutes and the temp needle just slowly climbed to almost red. So I turned the truck off, popped the hood and felt the upper radiator hose. It was cold, but as I went along the hose, It got hot near where the thermostat is where the hose goes into the top of the engine. As I kept holding it, I could feel bubbling. Is this the thermostat having issues?

tsduke

Certainly sounds like the thermostat is stuck closed. Otherwise you would have hot water circulating throught the radiator and the hose would be hot to touch.

tom5170

I cant get the bolt off the thermostat. Ive tried wd-40 and it still wont budge. I dont know what to do!

tsduke

Will the bolt back out at all?

tom5170

I turn it to the left and it wont budge. I am trying to not strip the head. Is there anything I can buy that will loosen it... like something made specially for stuck bolts?

s34n

try a penetrating lubricant as it is more for these kinds of situations opposed to wd40. another trick i read on a similar thread was to take a pot with boiling hot water and slowly pour it on the thermostat to open it up.

tom5170

Went to auto zone, bought a can of PB blaster. Sprayed it on the bolt in five 20-30 minute sessions (spray it good and let it soak for 20-30 minutes and then spray it again) and still nothing. I tried to loosen it with all my strength and it still didnt budge.