2000 ram t-stat not opening

[driver540]

got a 2000 dodge ram 1500 w/5.2. have flushed heater core and installed new t-stat. Its not overheating, but its not getting up to operational range....thus not letting the t-stat open and not allowing any heat. Could a stuck clutch fan be keeping the engine too cool for the t-stat to open?

[Chris Stewart]

The thermostat opens when the operating temperature is reached.
The entire time the engine runs, engine coolant is circulated through the heater core.
You might have an issue with the blend door allowing cold air to delute the warm air from the heater core.

[Chris Stewart]

Here's some info,

http://www.cumminsforum.com/forum/98...lend-door.html

[driver540]

I have seen all of this info before. Thanks for the link. But....why isnt the coolant getting hot enough to open the tstat? Upper radiator hose stays firm regardless how long it runs. And the upper hose isnt getting hot....just warm.

[driver540]

UPDATE: Took blend door motor off and manually shut door. Still no heat and engine temp still not getting to 190. Checked clutch fan...seems to be ok. Has a new thermostat. Heater core flushed and flows freely. So only thing left would be the water pump. Whats the chance of that being the problem?

[aleekat]

Usually if the water pump goes bad, it will overheat. I would pull the new thermostat and test it in boiling water. Seen them bad out of the box. Actually sounds like your thermostat is stuck open.

[driver540]

That will be my next thing to do. I just thought it couldnt be that because the upper radiator hose is firm all the time. But yet again....it could be partially stuck open. Thank you for the response. Will update as soon as I get it changed.

[driver540]

Okay. Pulled the thermostat and found an ungodly amount of permatex all over. From what I found I figured it was put in wrong and the amount of permatex did not let it seat properly allowing it to bypass. The previous owner was upset when he saw due to the amount he paid for the thermostat replacement. So...I have better heat...not like it should....but I need to do a system flush because it blows hotter with rpms up. Thanks to all for the responses.

[aleekat]

Originally Posted by driver540

Okay. Pulled the thermostat and found an ungodly amount of permatex all over. From what I found I figured it was put in wrong and the amount of permatex did not let it seat properly allowing it to bypass. The previous owner was upset when he saw due to the amount he paid for the thermostat replacement. So...I have better heat...not like it should....but I need to do a system flush because it blows hotter with rpms up. Thanks to all for the responses.

Probably need to flush the heater core also.