My water pump busted a few weeks ago on my '04 Ram 1500 V6 and after changing the pump it started overheating. I took out the thermostat and it ran cooler. So i flushed the system and changed the thermostat. Still overheating. I took the radiator out this morning and flushed both ends and water is passing through both ends of the radiator just fine. I flushed everything again after reinstalling my radiator and changed the thermostat again. Still overheating! This is confusing because I can touch the bottom hose at the radiator and its normal but the top hose is HOT. It should be the stat right???

 

Thats what it sounds like, change it, they are cheap

 

You are right, this is confusing. With the radiator cap off do you see water moving in the radiator? Was the engine overheating with the old pump? Assuming the old pump was only leaking out it's seal or weep hole? If there is a water restriction within the system could the wrong gasket or something similar have been used when you installed the new pump blocking a hole? I'm not familar with the V6 so I'm just picking on the simple stuff. The thermostat can be tested in a boiling pan of water to see if it is opening. Good Luck..

 

Thanks for the boiling water trick. That helped tremendously. It was a bad thermostat that was brand new!!! I cant believe it was 2 bad thermos in a row but it was. Thanks for the help guys..

 

Hi Greg. Jim here in Ukraine. I was reading your comments to Ponchoc above about his thermostat problems because I think I'm dealing with something similar over here. My truck (2003 Ram, 4.7L V8) has been running really hot lately - especially when in a city driving environment - and from what I could tell the problem is a faulty thermostat. I came to this assumption after checking and finding that the upper was very hot while the lower hose was much less hot when the engine was fully warmed up. I tried removing the thermostat only to find that now the engine REALLY heats up - way into the danger zone; I even had to stop every mile or so to let the engine cool as we just kinda "limped home"...

Anyway, I had heard about the boiling water trick too and decided to try it this evening. And by God the thermostat indeed DOES open at the boiling point. But here's the issue: At what temperature is the thermostat for this truck actually supposed to open? The mechanics over here (familiar with American cars) say that the thermostat should open at 88 degrees Celcius. But boiling waters is already 100 degrees. If I immerse the thermostat in 88-90 degree water it is closed.

Am I nevertheless dealing with a faulty thermostat? Any thoughts? Cheers, Jim

 

Make sure you burp the system well and get all the air pockets out. Also, I added Royal Purple's Purple Ice to my coolant and it's noticeably cooler when towing.