Trace

Hello Everyone.
I purchased my Dodge Diesel in 2001 new with only a couple of miles on it. Now 8 years later and 270,000 on the truck I notice that the heater in the cab just doesnt put out like it did new. I changed the thermostat twice in the last 2 months and the radiator is full of 50/50 blend. Taking the cap off and letting the truck get warm I can see the water moving and then eventually start to run over the top when the guage inside reads 190 degrees if I leave the cap off long enough.

The overflow container is filled to the proper height when the truck is cold and Im running cardboard over the radiator (about 75%)
The truck MAYBE has had one radiator flush but looking at the fluid, it's still nice and green and I dont see anything floating around when the thermostat starts to open and water is starting to move.
The thermostat never tops 190, but drops A LOT when in idol.
I can start the truck on a cold morning (right now its about 4 degrees each morning or colder) and even after a hr of idol the truck will only thaw a circle on both the driver and passenger windshield about the size of a paper plate. And, driving down the road with the heater on high, its only pushing out warm air at its best..

So, Im lost on what to look for, but Im tired of freezing my **s off in the state of Wyoming!

Thanks for any advice in advance.

Tracy

Mountaineer

I would say the heater core is shot .

Doj Dewd

i wouldn't be so quick to jump to that conclusion.

i thought the same thing with mine. i bought a new core because my heat was poor at best. at the same time i also drained coolant and ran a system flush to clean everything out. i then put new coolant in. heat was MUCH better after this - so i thought heck ya! - wait till i replace the heater core. replaced the heater core and noticed little to no difference, but gained a leak to boot, plus took a few hours of my time.

if i were you, i would run a flush through the system to get it good and clean and to loosen up any 'gunk' in the system.

i used a fleetguard product from cummins. the name of it is 'restore plus'

you can use the recirc setting on the vent control in the meantime, you can remove the fan, block the grille/radiator, and high idle the truck while it sits.

Copenhagenjunkie

Sitting at idle in those temps wont heat up the truck with the large cooling capacity. Being able to see is important though. Use a stick from seat to throttle peddle to get the idle up to at least 1000-1100 rpms to help build engine heat (poor mans high idle).


How is the air movement? Could be debris blocking air flow. Not sure on your model but can you pull vent cover below windshield and reach down into the HVAC box to a grate/filter? Pull out the fan and feel around. Do the back flush on the heater core. The big difference I found was changing the water pump. The impellers were gone which reduced flow. I also found that NOT using the high speed on the fan created hotter air.

Trace

Thanks for all the answers so far... As far as air flow, I still have plenty of that. The blower went out a couple years back and I ordered a used replacement from a online junk yard. It worked for about a week or so and then started squeeking. Still squeeks to this day (lol).

Last year, the low and medium speeds quit working and after a test I found the switch and blower motor to be okay, but this little part between the two went out. Expensive part (cant remember the name). So, today.......... I have high speed fan and good air flow from all the vents.

Okay, Question: My thoughts before the post was to flush the system as well. I was afraid of doing that for fear that it might leave things floating around and maybe the debris would get stuck in my thermostat and keep it from closing..

How hard is it to flush my own system? I realize the thermostat comes out (3 bolts on the top of the engine that takes about 60 seconds to change). Do I remove the heater core hoses (is that possible)...Im just a little lost on the "How to" for this procedure.. Costs to have it professionally flushed? I live in the country and have 55 gallon drums to dispose of the fluid myself and would prefer to do the job myself as well.

Does anyone know the name of that little part between the fan switch and the blower motor that went bad? And a good place online that has either used or rebuilt parts? I just know that once I have heat, I will want a quite blower motor and 3 speeds that work again as well!

Thanks,
Tracy

94ram

x2 on the switch.

my switch only works on high now as well, however mine is probably different the 24 valves, but does any one know how to fix it for a 12 valve or where to get a new one?
sal

Trace

Sal,
I purchased a repair book from Checkers and after looking it up, it showed me that mine had a switch **** on the dash, (this little chip close to the blower motor) then the blower motor. It showed me how to test each one and after testing the only thing that failed was the chip in between the two.
Maybe just look at the wires leaving your blower motor and follow them just a few inches to see where they lead you.

Good luck on your repairs as well! :-)

infidel

Blower motor resistor, about $80 at Napa.

Trace

Thanks infidel...

johnh

the reason the resistor is bad is most likely the bearings in the blower motor are bad, creating a higher than normal amp load....all speeds other than high are regulated by the resistor.........

Doj Dewd

home flushing procedure:

drain current coolant from radiator, then
remove upper rad hose (driver side) from rad inlet only. leave it hooked up to tstat housing, then
insert loose end of rad hose into a tube/pipe to direct flowing water elsewhere (i used a shop-vac hose), then
insert garden hose into rad inlet, then
turn truck on and start flowing the water thru the garden hose. continue this until water expelling from shop-vac hose is relatively clear, then
pour cleaner flush into the system as per directions and run truck at operating temp as per directions, then
repeat the drain and flush with garden hose procedure until suds stop coming out, then
drain as much water from the system as you can, then
pour in the appropriate amount of concentrated coolant as per cooling system capacity/desired ratio, then
top up with water until full.

i used fleetguard product 'restore plus'
when pouring product into the cooling system, i poured directly into the block via the tstat housing (remove it)
during flushing procedures i removed the tstat from the housing to ensure full flow at all times.
be careful with the tstat housing bolts. they get quite warm and can strip/shear quite easily when warm (ask me how i know this)

slowflyer2112

A better ideal. clamp off heater hoses from heater core and disconnect them from heater core. Pour radiator cleaner in heater core using a short hose. let stand for 20 minutes and hook up garden hose and flush with water, be careful with the pressure. Re hook up heater hoses and test. If this does not work you may have to replace the heater core. dodges have a design flaw in that all the crap collects in the bottom of the heater core and slowly plugs them. Napa makes a filter system that you can mount on the cooling system, they are made for semi's.

Doj Dewd

this method only addresses the stuff in the heater core. it will be clean at first - but the rest of the system will still be dirty and that stuff will find it's way into the heater core shortly . . .

94ram

thanks i'll look at that soon

Trace

Thanks EVERYONE for your posts. They all make sense!

Its pretty cool to know that even though you have a thought on how to repair something, posting that question or thought will let you know if your headed in the right direction...

From Me and Mine, to You and Yours....
HAPPY HOLIDAYS TO ALL

Tracy