I've never seen a cooling system like the one on my truck.
I never did get the Draincock to open on the radiator.
But I did the best I could.

I did isolate the Heater Core, leaving the hoses connected to it.
I back-flushed it with water at standard pressure and a contraption I rigged up to seal the garden hose to the Heater Hose.
Dark Chocolate came out of it initially, then turned Rusty and I could see chunks of crap coming out.
I ran the water until the water was clear. Then I raised the two Heater Hoses above the Core and filled it with Prestone Flush and left it to sit for an hour.
When I hooked up the Garden Hose and back-flushed it again I caught all of the Flush fluid in a clean 2 lb. coffee can. Then I ran the water while ran clear, for 30 minutes.
Then I dropped the hoses down, so the Core would drain and left it to sit over night.

Just for the hell of it, I strained the retrieved fluid through a Paper Coffer Filter. It took 3 filters because thy kept getting clogged and quit allowing the fluid to flow through.
The first one just had fine rusty discoloration. The second filter caught stuff the looked like Rusty Snot. The third filter had 0.5 mm and smaller crap in it.

The next day I decided to fill the Heater Core with the New Flush Fluid again and let it sit in there for Four Hours this time. When I back-flushed it, the fluid was brownish and then ran clear.

Then I Pulled the Top Radiator Hose off and removed the Thermostat and re-connected the Hose. At the same time I removed the rusted the Heater Return Tube from the Water Pump. It came out easily.
I siphoned the fluid from the Return Reservoir and then siphoned the Radiator.
I inserted the Garden Hose in the Radiator Outlet and Back-flushed everything out the Heater Feed, Radiator Inlet and the Heater Return Pipe.

I blocked the Heater connections from the Engine after connecting all of the other Hoses.
I then added 2 bottles of Prestone Flush in the Cap Opening on the Cross-over tube and filled the remainder with water.
I started the truck and ran it until the hoses were hot for, but after 30 minutes it barely reached operating Temp because of the missing Thermostat.

I let it cool down and back-flushed it with water, like I did earlier. Once all of the openings were running clear, I siphoned the Radiator and the Return Reservoir, and installed a new 195° Thermostat and re-connected all of the Hoses, including the Heater Hoses.

I filled the system with 100%, until it wouldn't take anymore and started the engine with the Heater open and blower on.
I ran it until the Hoses were hot but it just blew cold air so I turned it off and let it cool down.

After 90 minutes I checked the Fluid level (Dry Hose at Cap) and added water t top it off and filled the Reservoir half way.

I started the truck and ran it with the Heater on and once it reached 195°+/- the Heater was blowing so Hot I could barely hold my hand nest to it. Very Hot, Where it was just warm air before I did this work.

I probably went overboard trying to clean every aspect of the system but I really didn't see an easier way.
I never did remove the bolts and drain the Lower Engine block.
But I'm happy that I did everything I could do otherwise, to really Flush the system. And the Heater is Hot enough to cook with.

Rich

 

dodgeramguy85

Same thing I do rad hose much faster and easier those drain plugs always jam up and even break off I never touch them had one snap off and that was it no more.

I dont know about using such a hard core flush system for the heater core you dont want to eat the inside of it out and need to pull the dash out to fix it.

Just an opinion

 

I'm just curious, but with the time and money that was spent, would it have been easier and just about as cheap to take it to a local shop to have it flushed by a mechanic?

 

This vid will tell you 3 options to clean a heater core.


As far as taking it to a shop to get it done...Thats usually not better. They just charge you a butt load of money and mess stuff up. My truck never sees a shop and never will. They can usually do jobs a lot faster since they have all the right tools and stuff but that costs money and who knows if they even knew what they were doing.

 

has anyone ever tried CLR in the heater core. Not sure if they have that in the states but in Canada it's the cats *** for removing calcium and rust scale. I use it all the time for my humidifier pad. and it's made out of aluminum as well with no adverse affects

 

Yeah we have it here. Never heard of anyone using it in a heater core.

 

I bet it cleans well. Unfortunately it says not to use with aluminum.

"What surfaces should I not use CLR on?
DO not use CLR on natural stone or marble, terrazzo, colored grout, painted or metallic glazed surfaces, plastic laminates, Formica, aluminum, steam irons, leaded crystal, refinished tubs or any damaged or cracked surface. CLR may etch older sinks, tubs and tiles. CLR is corrosive. Avoid contact with wood, clothing, wallpaper and carpeting"

 

I've always done my own Coolant Back-flushs until '04 when I bought my Miata.
All of my tools were at my house in St. Louis and I let a shop I've used for other things, do it.
After it was finished I got 2 miles and the Top of my Radiator exploded.
I ZOOMED straight back to the shop before it overheated, so there was NO DOUBT that whatever they did, caused the failure.
I got a free New Radiator but after that I decided to start doing my own maintenance and repairs again.

I watched that Youtube video and several others.

This was a cheap procedure. I used the following for back-flushing the Coolant System:
4 bottles of Prestone Super Flush (2 for Heater Core, 2 for Rad./Engine) @ $2.99 each (NAPA)
3/8" Ball Valve @ $8.21 (HomeDepot)
Two 3/8" x 2" Galvanized Steel Nipples @ $1.97 each (HomeDepot)
4 ft. length of 5/8" Garden Hose w/ female connector (scrounged from my junk)
Teflon Tape (Tool Box)
Total: $24.11 + tax

I bought a bottle of CLR, but decided against using it because I didn't want to possibly have to replace the Heater Core.
The label says it should not be used on Aluminum.

As far as the time involved, I'm 64, Retired/Disabled and single, with all the time in the world. I'm mild OCD/**** Retentive (take your pick).
When I do something, I don't start until I'm sure I've looked at it from all of the angles I can think of and don't stop until I'm satisfied that I did all I could to my ability.

Because of, in my opinion, the poor design of the Coolant System on this truck:
1. Engine Drain Plug behind the Motor Mount, WTFs up with that?
2. Radiator Inlet/Outlets at Mid-level instead of Top and Bottom.
3. The POS Plastic Draincock.
I broke the system down into 3 sections (Radiator, Engine, Heater Core) and Flushed and Back-flushed each independently.

I'm not trying to tell Anybody how to do this.
I ask for suggestions when I encounter something new or confusing, so I can make an informed decision.

I just wanted to share what I did, how I did it and why I did what I did.

YMMV
Thanks
Rich

BTW, a little background of me:
My father owned a 4 man Automotive Shop, so I had a lot of exposure to car and truck repair.
I was primarily trained by the Army, my MOS was in Heavy Equipment Operation, Maintenance and Repair, serving for 4 years.

 

Actually sounds like me I tend to over think and over work/over complicate my DIY projects to perfection.

Gets annoying even to me

 

That fits me to a T.