Bought my truck in September 2018. 2002 3500. Winter came and all I could get out of my dash vents on position 2 was 80°f. Position 3 was 75°f. Position 4 would blow cold air. Installed grill blanket, no change. Installed 190 NAPA thermostat, temp guage now runs slightly higher and more consistent but no change in vent heat temp. Installed heater treater, no change. Flushed heater core with hose, temp now at 110°f on fan setting 2 and 95°f on fan setting three. Guess I have a heater core replacement in my future. Watched Mopar mans vid and I'm going to wait till summer to do it because I have to work outside in my driveway.......

 

 

Can't wait!!!!!

 

???

 

Stocking up on beer for the party....LOL

When you put the heater treater did index the blend door? I would think if its not the heater is probably blocked up with debris. You ought to think about doing you evaporator while in there. All the foam are probably shot too. Did mine like you are going to do, in the drive way. Replaced the cracked dash also. Turned into a big job but difficult by any means.

Just now, dripley said:

When you put the heater treater did index the blend door? I would think if its not the heater is probably blocked up with debris. You ought to think about doing you evaporator while in there. All the foam are probably shot too. Did mine like you are going to do, in the drive way. Replaced the cracked dash also. Turned into a big job but difficult by any means.

 

 

Ya, I did the indexing on the motor. I dread the job ahead of me. Early spring or summer will eliminate one headache and make the beer taste better.....lol

I meant to say the job is NOT difficult, but I did take time with it and the beer tasted good while the project was on going. I spent a couple days on mine. I just hurry thru things I have not done before.

I need proof read better read better. I just DONT hurry thru things I have not done before.

 

Anybody seen my glasses???

Plugged heater core possibly too. With a 190°F thermostat it 163°F out of the center vents idling in zero degree weather. Even my 180°F is still cooking me in the cab.

You can try filling Heater core with https://clrbrands.com

But if it had leaks it will open them up

I have had three different vehicles that I just did a backflush of the core and if worked after just fine. I disconnected the heater core from the motor and ran some vinigar through it backwards and then ran hot water through it to flush it.

Still in all the best way is to pull the HVAC case. All the flushing in the world won't fix debris problems. 

 

In the meantime how about a heater buddy?

It’s not that bad. Just did mine. Going to redo I though next year as I cheated and did a quick fix by splicing the heater core pipes. Going to do evaporator and new dash and pull the heater box and do another heater core the correct way when I do it. I just wanted to get through this winter without freezing and trying to scrimp and save. 

I was watching Garage Squad the other day and they used a brand of cooling system flush that is supposed to clean up the inside of the cooling system to look like new again. They said it worked better at unplugging heater cores than the other brands they have used. I can't remember the name of it, but it can't hurt to try it. You probably have debris up against the evaporator core and that will have to be replaced, but for now make sure there are no leaves built up around your blower motor. You might get lucky and have some there that when removed, might just give you better airflow and heat for now until Spring time.

Edited November 30, 20186 yr by 99_Cummins_4x4

10 minutes ago, 99_Cummins_4x4 said:

I was watching Garage Squad the other day and they used a brand of cooling system flush that is supposed to clean up the inside of the cooling system to look like new again. They said it worked better at unplugging heater cores than the other brands they have used. I can't remember the name of it, but it can't hurt to try it. You probably have debris up against the evaporator core and that will have to be replaced, but for now make sure there are no leaves built up around your blower motor. You might get lucky and have some there that when removed, might just give you better airflow and heat for now until Spring time.

I say just replace the darn thing. It’s not hat hard. Geno’s Garage has a easy step by step guide. 

I agree to replace it, but if he has to work outside in freezing temps, and has nobody close to him to let him use their shop to get out of the weather, then this is an alternative that might allow him to get by until Spring with warmer temps.

I dropped the heater fan\motor and was able to clean most of the stuff out of the heater core by using a heated then shaped  tooth brush handle and also melting and bending a vacuum attachment.  A inspection mirror is also required.   It's not perfectly clean but not bad, I stay plenty warm in winter.  

Edited November 30, 20186 yr by bcbigfoot

I concur with the above in opening the dash up and replacing or at least cleaning our the heater core. 

 

That having been said, this is what I have done in the past with some very encouraging results. (NOTE: this is NOT what most would consider a permanent or even a long term fix and it DOES lend itself to a significant degree of halfass)

 

Get a Milton compressed air chuck nozzle, climb underneath the passenger side of the truck under the dash area and find the evaporator drain.  Clean any debry or obstructions from it. 

 

Now turn the ignition switch on and turn the heater switch to blow directly into your face and turn the fan up to maximum.  Leave it running.

 

Climb back under the truck and insert the compressed air chuck into the evaporator drain and seal around it with a rag or other means to seal off and compressed air leaking by and blow compressed air into the evaporator drain using intermittent pulses of compressed air.  

 

This will stir up the debry in the heater core/evaporator box and push it into the fan which will blow it out of the box into the vents and into the front seat area.  This may require a good bit of compressed air pulses to get whatever debry you can move with the compressed air.  It may not get all of it but it will get a lot of it and hopefully improve air circulation through the heater core, not to mention help to remove the crap that builds up around the heater core and evaporator causing corrosion and leakage down the road.  

 

It is NOT and ideal nor  first class solution but it sure does beat removing the dash and can hopefully put that explication producing task off for a while longer until it is absolutely required if coolant is leaking into the cab.  

 

I did this on my truck and blew all kinds of crap and debry out of my heater box.  You may see some of the foam rubber seals blow out as they dry rot over the years.  Not much you can do about that.   

I did mine in an afternoon start to finish in about 7 or 8 hours. if you can borrow a car it maybe best to do it over tow 4 hours afternoons when its warm out.

I pulled mine and I had a good amount of debris in mine, but I replaced my heater core when my ac evaporator died. Its best to buy both and follow the short method to pull the dash back like Mike has.

Another option is to run on MAC A/C with the relay pulled for the compressor. Then you can get some decent heat in the cab.

 

I may also recommend a 200F tstat too, the extra 10-15degress will cook me on regular vent settings on high i can still see 150F air.

I finally got around to replacing the original OEM 17 year old thermostat that had not worked in many years with a 195 degree thermostat.  Wow!  What a difference and improvement.  

1 hour ago, pepsi71ocean said:

Another option is to run on MAC A/C with the relay pulled for the compressor. Then you can get some decent heat in the cab.

I got mine on a switch, thanks to @IBMobile love it...

For the best performance of heating and A/C you should just replace both units in the HVAC case. While the case is out lube all the door pivots. Inspect the blend door coupler. Might replace the blower motor and resistor if they have serious age on them. 

 

Attempting to flush a heater is rather futile. There is no way to ensure all the tube got cleaned out. Years ago on my 73 Dodge Charger, I got bold enough to pull the heater core unsolder the ends and using wiper blade rods I rodded out the heater core and re-soldered the end back on worked great but the tubes were already thin and didn't take long for the tubes to leak afterward. The reason I when down this road was, I tried all the flushing and scale chemical I could with little gains. Rodding out heater core makes it function like new.

 

Being as most of the newer heater cores are now aluminum there is no way to disassemble and rod out and reassemble. Same thing with the evaporator. Best to just replace them and move on.

20 hours ago, Dieselfuture said:

I got mine on a switch, thanks to @IBMobile love it...

 

Do you have a wiring diagram for this?

20 hours ago, Mopar1973Man said:

For the best performance of heating and A/C you should just replace both units in the HVAC case. While the case is out lube all the door pivots. Inspect the blend door coupler. Might replace the blower motor and resistor if they have serious age on them. 

 

Attempting to flush a heater is rather futile. There is no way to ensure all the tube got cleaned out. Years ago on my 73 Dodge Charger, I got bold enough to pull the heater core unsolder the ends and using wiper blade rods I rodded out the heater core and re-soldered the end back on worked great but the tubes were already thin and didn't take long for the tubes to leak afterward. The reason I when down this road was, I tried all the flushing and scale chemical I could with little gains. Rodding out heater core makes it function like new.

 

Being as most of the newer heater cores are now aluminum there is no way to disassemble and rod out and reassemble. Same thing with the evaporator. Best to just replace them and move on.

 

I second this. I just wish i knew about lubricating the doors when I had it out!

3 hours ago, pepsi71ocean said:

Do you have a wiring diagram for this?

You need to read this thread.  The modification to the A/C switch is in it.