seveninc

07 5.9L 6sp

upper rad hose from engine to rad is hot
temp guage showing 95 (right in the center)
blend doors are working fine
rad is topped up, overflow is full, no visible leaks

the only problem is the 2 hoses running to the heater core (through the firewall) are not hot, not even warm.
at first it was just the lower one that was cold but now its both.

i thought it was my thermostat but im not sure.

the heater blows cold air on all modes even recirc.

if it helps i had a coolant leak on the lower part of the rad a few months ago but read where ground pepper in the rad could help fix it. it doesnt leak anymore after that but could that be causing a blocked rad or something

Foxborough

Sure sounds like a blockage in the heater core. Can you take off both lines to the heater core and blow some air to see of there is blockage? I would just use an air wand with a rag around it to prevent overpressuring it.
I don't know where the valve is that controlls the water thru the core, that may be disconnected or not working also.

seveninc

yeah ill give it a try and let you know. will i need to drain the coolant first?

Dieselbuilder

instead of air use water, garden hose that way you wont trap air in the core

infidel

Valves haven't been used since the '90s due to dead ends leading to blockage.
Most modern vehicles use a blend door that directs air though the heater core. Hot coolant always flows though the core.
Unless of course the core is blocked, which sounds like the case for the original poster.

seveninc

everything is frozen. i tried using a large squirt top water bottle but that solved nothing. it wouldnt even push the water through. im taking it down tomorrow for a heater core and radiator flush. hopefully thatll solve it.

Foxborough

Thanks a lot infidel, I haven't wrenched on a vehicle for a while and you just had to shine a light on that . Actually sound like good information especially about using water instead of air. I'll stay out of this . At least he will get a bump and get better advice.

pind

To the OP

Your ground pepper is your entire problem. it is good at blocking holes, just like eggs, or bars leak. They plug up the tubes in the heater core. The rad isn't so bad, as the tubes are larger, and there is more flow.

You need to get that crap flushed out of the system, then fix it properly, and refill it accordingly.

seveninc

how do i fix it properly without shelling out the money for a new rad?

johnh

how much pepper did you use?.....sometimes trying to save a little money costs a lot

Brian08Q35004x4

Look where cheap got you. It fixed one problem but created another. What about inside the motor? What is it clogging in the passages in the head and block? Pull the radiator and take it to a radiator shop. I have had many repaired and not at the cost of a new one. . Where was the original leak? Was it the core or just a broken solder joint or cracked in one of the the tanks? It is a it 25k truck that may be damaged down the path and even take more too fix.

tech-eh

So here is what I have done in northern Ontario in a similar situation . Find a basement parking garage lower level works best I am thinking you don't have a garage
park it with the rad towards the wall ( nose in ) you can work on it quietly and in some warmth . Alberta is coooold this time of year.Drain a liter out of rad add 3/4 a bottle CLR run engine 20 min rad cap off . All the junk is now in the rad fluid but you should have heat now . Drive home with the rad cap off it will evaporate some on the way home but its cold out and drain all the coolant. You have to get rid of all of it .Power flushing the heater core/ rad with a hot water hose hooked up to an inside tap works good too run it till its clear .No hose access drain the engine completely in the parking garage and add water from five gallon jugs with baking soda 1/2 cup per five gallons in it till full .Do it twice .Then immediately add all new coolant till you get the proper mix ratio .Use a cheep rad fluid tester to be sure. All this will free up heater core and rad enough to get you by till you save up for a new heater core and rad
The CIL will have eaten away the calcium /corrosion everywhere and freed up the
gunk in the HEATER core which will cause it to be weeeeak and possibly leak . The only stuff to use temporarily is Iron Tite by quick way from California .Bars and the other stuff is just too coarse .Most auto jobber will have it
It will plug all the leaks for about 3 months RE spring and still allow proper flow but you will eventually need to fix the issue permanently before it gets hot out worked for me to get the truck home .good luck

seveninc

it was a pinhole leak about 4-5 inches up from the bottom on one of the fins. im not sure of the proper terminology.

i read on the forums where someone said these rads are cheap and cant be soldered. is this true??

if im shelling out money to get a new one is there an aftermarket one that i can upgrade to because we all know that dodge parts and not the greatest.