Hello. Here's the situation. 2008 dodge caravan STX 3.8l
This problem only seems to happen when it's cold old. It's been fine all summer long. And is starting to happen since the temp has dropped. I'm in Maryland so it's dipping below 40.
Start the van up and let it warm up. Hear comes up fine. Start driving and it goes down. Than a red lightning bolt light comes on after a while and the temp goes completely down and stays down no matter how long I drive. I replaced the stat and the coolant temp sensor. Any suggestions?
Thanks in advance.

 

The red lightning bolt is a warning lamp for the electronic throttle body and usually when it comes on you have limited throttle response. Wouldn't have thought it would cause a no heat complaint.

Does the upper hose get hot at any point?

 

Ill check it again today. I don't notice notice any difference in throttle response. Thou I didn't pay it much attention. I'm gonna try having the coolant system flushed next. I'm wondering if there's air in the system. Not sure why that would cause that light to come on and not too sure why it only happens when it's cold out. Seems weird. Perhaps if the comp thinks everything is cold and temps not coming up it sends a signal that activates that light so you don't push a cold motor to much. Idk. Just blasting out random thoughts lol

 

This is more of a question to Tizzy1. All I know about this is that it exists. On 4th generation vans there is a check valve in the heater lines under the hood. Exactly what it does I don't remember. Did that check valve carry over to the 5th gens and could this be causing baldelock's problem?

 

Thanks for looking into this with me guys.

So I'm messing with it today. Got the front end up on an angle. On the curb. My outside air temp is reading 57 degrees. Coolant temp is up to the third small hash mark. Upper and lower hose are both hot\warm. Running heat full blast in the front and rear. Radiator cap is off. Waiting to see what happens. From what I remember it only happened while driving. Like I said before only happens during the winter. Go figure. Lol

 

New update.: hit a deer Saturday night. :/ so I won't know much until Monday. It may be totaled. So I may not have to worry about it. :/ 2 car payments left. I have the luck of the irish

 

Are you OK?

 

We're all good/ thanks

 

That's not totaled.....at least that's my guess!

Cougar, the check valve was to keep coolant in the heater core and get rid of that water fall noise they used to make. Don't believe his van has that valve anymore.

 

Were back. Took them long enough. Over 8K in damage. But they fixed it. And made my payment this month. As it gets colder we shall see about this check light and what happens. I'll keep y'all posted. Merry Christmas everyone!