[PMD1969]

I have an 2002 Lincoln Navigator that has a two system AC/Heat systems in the SUV. Since we are in Texas of course we are using the AC for most of the year but low and behold we do have a short winter season here and need the heat.

The front system appears to be clogged but maybe not? I have checked the blend door which is operating just fine and the actuator which is operating just fine. When the dial is moved from cold to hot and in reverse the door opens and closes as it is supposed to.

I had a mechanic check the radiator and heater core since when I put my hand on the heater core (inside the vehicle) it was cold. He claims to have "tried" to flush the system but I would like to have a go at it before we have to go the ultra expensive way of replacing the heater core itself.

I would like to try a detergent or CLR to see if something like that will have an affect on getting the blockage to come loose and finally come out of the heater core.

If you guys have a product or a way at getting this done please share that with us.

Thank you!

[dxeven]

I just had a similar situation on a 2000 Ranger we recently bought from my wife's uncle. During the single-digit temps last week, my son informed me the heater didn't blow cold at all. I just backflushed the heater core using straight hot water. I blew out what appeared to be Barr's Leak from someone's previous repair attempt. Kept alternating flush direction to get as much loosened up and flushed as possible. Works great now. For the first time ever, I got lucky and the easiest "fix" worked. GL

[DOC]

is the heater hose hot? And does the heater hose have a valve in it?

[GT182]

Try some CLR. I did that to the heater core in the Ford Taurus we had. After using it twice it cleaned it out and no problems after. Just make sure you only ad the CLR to the heater core's hoses, not the engine. Let it sit in the hose and core for 15 minutes. Flush one way and then the other with the CLR.

[PMD1969]

Originally Posted by DOC

is the heater hose hot? And does the heater hose have a valve in it?

Both hoses seem to be hot but they have multiple attachments to them. This is a TWO AC/Heater system as there is one in the back of the SUV as well. They are both attached to the same hose system and the rear one blows very hot.

[PMD1969]

Originally Posted by GT182

Try some CLR. I did that to the heater core in the Ford Taurus we had. After using it twice it cleaned it out and no problems after. Just make sure you only ad the CLR to the heater core's hoses, not the engine. Let it sit in the hose and core for 15 minutes. Flush one way and then the other with the CLR.

Only the hoses? Does this mean that the CLR will have an bad affect on the aluminum in the system itself?

[PMD1969]

THis SUV and the heater core hose system is set very far back in the firewall as is the engine. I cannot get my hands back to the firewall to get to the heater core pipes so I will need to use the hoses at the front of the engine to do any flushing.

The shop that I take it too I really trust the owner. But I don't trust the mechanic that did the work. When I got the SUV home I found a TON of rust colored water in the reservoir which tells me he really didn't back flush then re-flush the system forwards again afterwards. I don't think he tried very hard since he then wrote up a very long and very expensive heater core replacement quotation.

[GTOWAGON]

take off the hoses and back flush with garden hose flush from the return side to the supply side usally the smaller hose is the return. I have also had luck by filling the heater core with CLR and then flushing the CLR will loosen up the gunk in the core. also does the vehicle have lifetime coolant in it if so does it look sludgy at all if it does flush the whole system

[GT182]

Originally Posted by PMD1969

Only the hoses? Does this mean that the CLR will have an bad affect on the aluminum in the system itself?

No it shouldn't. My Taurus had aluminum in it's system and it didn't hurt it. Just make sure you flush them really good so no CLR is left when you add antifreeze back to the system. The heater core was aluminum too..... as was the water pump.

[geeteeohguy]

I have used vinegar to remove rust from cooling systems. Mix it 50/50 with distilled water and let it soak for a couple of weeks. The trick is to then use washing soda (not baking soda) mixed with distilled water afterwards to neutralize the acids left behind. Not sure if CLR is acid or alkaline, but either way, you should neutralize it when you are finished with it.

[Formulabruce]

Those hoses have special connectors on them to hook to the plastic piped heater core. You need a special tool, Once you do a Houdini and get there. Try to find a spot further forward and then pinch the rear heater hose .
Vinegar is great...