I need some help diagnosing my heat problem please

[dually]

Thanks for the tip. I dont see dusty roads at all. One time i blew a hg and had oil all over the place. Another time i had the puke tube blow and cover the bay. Then i built a breather and put it on the pass side so i had a stream of crud flow. I have a hole under the hood for a scottys II intake. I ran the truck with that hole open for a wile. That ac picture i posted looks like a radiator/puke bottle problem if you know what i mean. Before i lowered the puke tube my radiator was covered like the ac in the picture. Thats my guess anyway. Oh yes i also at one time ran open breathers on the top of my valve cover

[Mopar1973Man]

Scotty II air Filter those are rare to hear about anymore...

[dually]

They really work. The filter is as long as a 5 gal bucket. I all ready had the hole in the cowl because i knew it was just a matter af time until i found a scottys plus i tryed to make my own. I like the free air it grabs like the 70 ss chevelle.

[JoeDiesel]

I have the same problem as the OP but I changed the heater core and I still don't get good heat like I use to. what I've done: changed heater core, flushed system, added cummins t-stat, replaced blend door motor shaft(wasn't broken),all 3 blend doors move(glovebox,2 under dash) Symptoms, now that its colder out, upon start up the windows fog up, the hot/cold regulator doesn't regulate so its either cold or hot no in between. water pump works well no leaks.so im at wits end! any input appreciated.

[dripley]

i have similar problems as you. biggest differance is i have not tried to repair anything yet. heat is either full on or full off, not as warm as it used to be either. i dont have the fogginh problem though. did you reindes the blend door motor when you repaired the shaft?

[Mopar1973Man]

I have the same problem as the OP but I changed the heater core and I still don't get good heat like I use to. what I've done: changed heater core, flushed system, added cummins t-stat, replaced blend door motor shaft(wasn't broken),all 3 blend doors move(glovebox,2 under dash) Symptoms, now that its colder out, upon start up the windows fog up, the hot/cold regulator doesn't regulate so its either cold or hot no in between. water pump works well no leaks. so im at wits end! any input appreciated.

upon start up the windows fog up

That means there is another coolant leak in the HVAC box again.

the hot/cold regulator doesn't regulate so its either cold or hot no in between.

Look down at the base of the HVAC case and check and see if the shaft is moving properly. You might have to take a jump over to Heater Treater and get a new bushing.

replaced blend door motor shaft(wasn't broken),

Did you check the stepper motor for proper operation too? I know there is a rheostat strip in the stepper motor that controls positions it might be wore out...

[dennhop]

When I had an issue with my heat, I found that the stepper motor in the hvac box was my culprit. What happened was that the two contacts that provided power to the motor had broken off. 5 minutes later, and some solder, and it works as good as new now. Might check out your motor.

[JoeDiesel]

That means there is another coolant leak in the HVAC box again. Look down at the base of the HVAC case and check and see if the shaft is moving properly. You might have to take a jump over to Heater Treater and get a new bushing. Did you check the stepper motor for proper operation too? I know there is a rheostat strip in the stepper motor that controls positions it might be wore out...

how do i check if theres a leak? i've replaced this already and it wasnt broken. this i didnt know, how do i check that? i also noticed that turning right i get a blast of hot air when the engine is up to temp.

[Mopar1973Man]

Passenger side of the trans hump is the stepper motor for the blend door... Turn the ignition to ON and not start the engine. Then turn the temp knob left to right and watch the shaft.

[JoeDiesel]

yup checked it and it does turn.