Coolant drain and refill

[sftibbs]

No, the water is not circulating in the radiator. I noted today that when the engine gets to running temp, the top radiator hose is cold and the bottom hose is hot. The water in the radiator remains cold.

[tom]

Check your thermostat. If it doesn't open, the upper hose will remain cool, while lower hose will heat up, your motor will overheat. An easy (not real accurate) check is put your thermostat in boiling water. It should open.

[tmodel66]

I'm not being a Know-it -All  but did you put the thermostat in up-side down? In a hurry to get it put together I have seen strange things happen.

[sftibbs]

Being at a loss I did check the thermostat and it was in correctly. There's no indication my old thermostat was bad as the car ran fine prior to changing the coolant. I bought a new one thinking that somehow the old one was bad (however changing the coolant doesn't make a thermostat go bad in my experience). So at this point, it's hard to believe both the old thermostat and the new one are both bad, but stranger things have happened. I will take the new thermostat out and run a test and update the post. Thanks for all of the assistance.

[69Z28-RS]

If the water isn't flowing, and the thermostat isn't impeding the flow, then si there anything else that might be impeding flow?  or... Perhaps your water pump isn't pumping....?

[tmodel66]

If the coolant is not circulating it could be the water pump. Does pressure build up on the hoses when it's running with the cap on the radiator? I mean do the hose feel tight or are they easy to mash on?

[sftibbs]

They are easy to mash on. Certainly not ruling anything out, just think it odd that the water pump, thermostat and radiator were functioning fine prior to changing coolant and now one of those parts is not functioning.

[sftibbs]

Well just for fun I put in another new thermostat and everything is working as it should be. Amazing but true...thanks again.

[Mike S]

 That's good news it is working. Are you able to push the poppet away from its seat?
I usually will work the poppet when new because I have seen a few that stick pretty tight until worked.
Also, putting it in a pot of water on the stove is a good pre-install test (when the wife isn't home)  

Thanks for the follow up. It's always good to hear what the fix is for problems.
Mike

[sftibbs]

Good question. I did take the time to test the new one with the boiling water method and it did open up. I had to test the one I took out just to see and it failed to open.

[tmodel66]

Glad you caught it instead of taking off and ruining a motor.

[69Z28-RS]

Just curious:  what was the brand of the 'new one that did NOT work'??
shows to go ya..   sometimes the new stuff is bad too....

[sftibbs]

Superstat from Napa Auto Parts AND made in the USA! Napa had no problem with the exchange...just one of those things.