heat trouble shooting from @ A/O

[ak_petey]

Ok here goes, at really cold temps I can get semi warm air blowing through my air vents. The engine's operating temperature is pretty normal (running at 180-190'F). On the A/C setting I get plenty of warm air, but cannot run it for too long because it fogs up the inside of the truck.

I was just wondering if I could establish a basic (low cost) trouble shooting/solution thread for getting warm air back in my truck. I was also hoping to get other methods and/or ideas of how to do this cheap.

This is what I have in mind so far:
check thermostat
flush heater core
flush radiator

[akram]

Flush cooling system would be my first step. This is something we overlook way too often. Running the AC shouldn't allow you windows to fog. When you run your defroster in runs the AC to dry the air so you are blowing dry air on your windows to keep them from fogging up. so that part doesn't make sense to me. But definately start with a coolant flush. Has the truck ever had one? doing this every few years is a great thing. Another thing is to check if the blend door is working. Not the door that changes the [ath of the air flow but the blend door that "blends" the cool and hot air. These had a tendency to go bad on dodges.

these are just my opinions and should be taken with a grain of salt.

[ak_petey]

any suggestion and idea is a good one. because many of the ones we havent considered or overlooked are the cause![COLOR="Silver"]

---------- Post added at 08:43 pm ---------- Previous post was at 08:21 pm ----------

[/COLOR]hmm I have never looked under my dash in that cold door area.

also- It seems that the A/C setting circulates the interior air.

[88XJ]

Not to sure about your particular Dodge.

Blender door- usually operated by vacuum on older trucks and electric on more modern heating systems with fancy heat control, easy to check. Have Girl Friend operate the temp control and look and or listen for the actuator to turn the lever, I have actually pulled apart a heater box to find debris blocking the fresh air door from closing all the way. (that was on older trucks, you got to love those little animals)

AC-Usually there is two settings on the AC, one circulating and one not, or a MAX A/C or A/C the one that recirculates the air can cause your system to fog up the windows. The fresh air option is the one you want to use. if the blender door is broken then it can cause the fog

Heat= -50 to -55 degree max for your antifreeze level, if you drop it colder then that it can actually stop the flow through your heater core on the really cold days, I usually run mine around -50.

With your truck at operating temp check the heater lines to see if they are warm, if they are not then you might have a blockage with the valve, but since you get really hot air with the AC probably not the issue.

I run a cover on my Diesel, it helps with the motor heating up but I never noticed it effecting the heater one way or the other, I just rode in a friends truck and just from idling too long his truck actually got cold, I have just a little but newer truck and mine doesn't do that.

Don't know if that is at all helpful, did this just start happening or has it been a regular occurrence? what temp do you start to notice the lack of heat? Do you know others in a similar year truck to ask them if they experience the same problems? It may be just a bad design all together.

[ak_petey]

the lack of heat usually starts at -15 to -20
after I run some diagnostics I will report back. thanks!

If anyone has anything else to add feel free. I think Don gave me plenty to check

[Zukman]

Some times you mite have to block your fresh air intake, most newer vehicles exchange 20% or more of the air in the cab which is to much. use some tape to block a little a off at
a time. If you block to much you will get fogging. Also see if your a/c is running al the time, if it is then there is your problem.

[ak_petey]

I turned the temp regulator to hot and cold. I heard the motor door opening and shutting. it did not seem to foul up. maybe when I get it in the garage I can inspect it further. But Mel's suggestion to get the thing flushed is definitely on the to do list.
Easiest way to do this?[COLOR="Silver"]

---------- Post added at 06:27 pm ---------- Previous post was at 06:26 pm ----------

[/COLOR]anyone have any tools/connections I can borrow to do a system flush?

[akram]

Go to walmart and buy the cheap prestone back flush kit. It comes with adapters and directions. It is what I always use and works perfect. Also get some radiator flush as well. That is what's going to help clean it all out. This may go without saying but I'm going to say it. Be sure to use water that is filtered. A lot of places like mine don't have a filter on the outdoor faucets or water hose connections.

[ak_petey]

hm this sounds almost too easy

[akram]

It is really easy.

[ak_petey]

I remember years ago when I took it into fairbanks radiator and muffler, they flushed it both directions.
im hoping the kit allows for this.

how much distilled water do i need?

[akram]

If you are going that route you need a water tank. I hook my water hose up to the washer spout and turn it on. It is quite a bit man. Back flush is really all you need. No point in wasting time and money.