i flushed the rad alone the block and the heater core all separately until it ran clear for at least 30 sec to a minute the reverse flushed the same way and just to make sure a third time the last time no it ran clear right away filled the system no change so i tried chemical flush and flushed the whole system with water again still no change it runs below cool even in warm weather the warmer it is out the better the heat works i can drive it shut it off and the heat will crappy but a half hour later when i start it again the heat is better

 

and it has been running cool since i flushed and changed the thermostat the whole system is clean i am 100% clear on that and the heater core is good blockage i dont know most people who own a dodge around me put cardboard in front of the radiator because of the heat not being hot i think that its that the system is working to well and wont heat the truck

 

What temp thermostat did you put in? OEM is a 195.

The "new" thermostat can be bad. A lot of auto parts are junk now.

 

I think a proper working thermostat would keep the radiator toasty for you. If it's stuck open, it will never heat up.

You might want to remove your thermostat, put it in an old pot full of water on top of the stove, then heat until it starts to open and check the water temp with a meat thermometer. That won't cost you a penny to try unless your wife sees you using the good cookware for something that's had coolant all over it.......

 

I think there are 4 different components going on here.

1) Gauge accuracy
2) Sensor accuracy
3) Thermostat functionality
4) Cold weather

1) The gauge needle remains at the far left end of the scale until the clus- ter receives a message from the PCM indicating that the engine temperature is above about 54° C (130° F).

Each time the cluster receives a message from the PCM indicating the engine coolant temperature is between about 54° C (130° F) for gasoline engines and about 129° C (264° F) for gasoline engines, the gauge needle is moved to the actual temperature position on the gauge scale.

Each time the cluster receives a message from the PCM indicating the engine coolant temperature is above about 122° C (251° F) for gasoline engines, the gauge needle is moved to the appropriate position on the gauge scale, the check gauges indicator is illuminated, and a single chime tone is sounded. The check gauges indicator remains illuminated until the cluster receives a message from the PCM indicating that the engine temperature is below about 119° C (246° F) for gasoline engines

2) All sensors lose accuracy with age. I don't know how much accuracy they lose, though.

3) Most well-made thermostats have gone to the fail-open design instead of the fail-closed design. However, while they did this so that engine damage would not result from a failed thermostat...If you do get one with a bad spring, it might be indefinitive. At least when they failed closed, you knew it right away.

4) It's cold outside. You northerners that are ecstatic to get above freezing, think about what that wind chill is when you are out walking around in a 20-30 MPH wind. Now think about that as you're driving at 30 MPH, or even as you sit still, the clutch fan is still rotating and pulling air through. The radiator fins are probably getting an effective wind chill in the single digits at low speeds and significantly negative at highway speed. Plus the air is cold as it goes around the engine block, so the whole system is fairly chilled.

I did an experiment on monday. Going 70 MPH with cruise on, my water temp was bouncing between 183 and 185. I reached down and flipped on the radiator fan, and the temp dropped to between 179 and 181. That tells me I had more air going through the radiator with the fan on, than I did going 70 MPH. Think about THAT wind chill for a second, and it was still a nice 60 degrees outside.

When we were stuck in snowmageddon (The south's term for any non-aqious precipitation), I went to school in an air temperature of 25 degrees at 30 MPH. My IAT was 87 and coolant was at the upper end, kicking on the radiator fan at 192 and shutting it off at 187. I manually turned the radiator fan, and coolant temps fell down to the point that the thermostat closed- I was watching my coolant temps bounce back and forth about twice a minute between 172 and 179.

 

If they had heat before though then what has changed? Yes, gauges can be inaccurate. But if the gauge is reading cold and there is little/no heat then that kind of confirms the gauge reading.

If the gauge was reading "normal" then I'd be looking at a clogged or partially clogged heater core.

It was -2º fahrenheit here this morning. Within less than 10 minutes my engine was running at it's normal location on the gauge, the needle splits the "2" and the "1" on the dial. Inside, the heat was cranking and my truck was a sauna, as always.

They shouldn't need to block the radiator if the thermostat is functioning properly.

There are a lot of crappy aftermarket parts nowadays. I'm not implying that anyone is buying a cheap part it's just that you don't always know what you get when you go to the parts counter. It comes in a white box, you bring it home and install it.

Feel the radiator hoses, engine off of course, after it's been run. Are they hot/warm/cold?

Why was the thermostat changed in the first place?

 

This is true.

I get all the important stuff at NAPA. Even as much as o'reilly's sponsors drag racing, some of their stuff just is not great quality. NAPA Gold or go home.

 

i changed the thermostat because the temperature was bouncing 15-20 degrees in either direction did it once and thought why not just change it its cheap and easy enough i got a napa thermostat cant remember what kind exactly but after i started tearing into it i found alot of build up scum and rust on the thermostat so i flushed and filled i took the truck out yesterday stopped at a friends garage and pressure tested the system and the heater core alone against his dakota and it was all checking out the same and he has great heat i might just replace the thermostat again and go from there the thing i dont understand is before i changed the thermostat and flushed the system i had great heat then after the heat just sucked so i am at a lose i am out to believe i got a bad thermostat

 

I flushed my lines going into the heater core and now have magnificent heat. It got to the point today where i had to turn the heat off because it was way too hot. and sitting in an open garage about 5 mins of idling i had good heat. So im very well pleased in the results

 

ok soo it got warm this week here in pa went from 30 degrees and below to the 60s and i had great heat in minutes once it was above 30 no overheating the temp gauge was in the same place as it has been so any ideas