Originally Posted by badtlc
Originally Posted by StevieC
You said the thermostat is opening at 190F which means it's opening at too cold of a temperature than Chrysler intended. As the heater core draws heat from the engine directly, if the thermostat is opening too early the cold coolant from the radiator moves into the engine and further drops the 190F temperature of the coolant that is going to your heater core which is why you have a heat problem.
In my 2018 Caravan with the same engine it gets to full operating temperature from cold start after driving about 10-12 minutes at the current outdoor temperatures hovering around 30F. I don't get reasonable warm air until I hit 197F as per my electronic drivers information center coolant temperature reading.
When in traffic idling a lot the coolant will get as high as 220F at times and that is when I get really hot air coming out of the vents. (This is when the rad fan kicks on high and reduces it to 200F and then resumes low speed fan speed) They are designed to run this hot for better fuel atomization. Even my Journey ran this hot. (2 thermostat setup in that vehicle, but the hotter thermostat was 203F)
So if your thermostat is opening at 190F then this is why you have no heat because your system was designed with 203F in mind. It's also affecting your fuel economy.
Ignore 190 vs 203 for a minute. A new t-stat won't speed up the time it takes to get to 190F. The heat and everything are OK once the water temp hits 150F or so, it just takes forever to get there and if it isn't because the t-stat is stuck open, what else could possibly cause the engine to heat up so slow?
I was just going based on you saying "The thermostat is opening/closing at 190F" and you verifying this
It could be partially open before then or sticking open just enough that it slows the warm-up. You need it to be working 100% to get heat and for it to warm up quickly especially in our vans where they run the radiator fan all the time on slow and only kick it to high when the thermostat opens. This leaves the coolant in the radiator really cold so if it's leaking in via a partially stuck thermostat for example, it's a big problem and would contribute to the symptoms you describe.
Note: The radiator fan doesn't start on slow as soon as you start the vehicle but after a delay period as set by the ECM, It continues this between high-speed fan cycles there after.