Heater Core reverse flush.

[RESTREC]

Is it logical to just reverse flush the heater core thru the outlet hose, having disconnected just the heater core hoses ? I'm looking to clean the scale built up on the heater core and not the rest of the cooling system.

[mastermech]

you should reverse flush the entire system. you do this by removing the thermostat and replacing the housing and run water from the outlet side of the heater and drain the radiator do this several times until the water runs clear. replace the thermo with a new gasket and close the system, fill it up, start the van, wait for the thermo to open then fill as necessary to get the proper level of coolant. hope this helped

[RESTREC]

Originally Posted by mastermech

you should reverse flush the entire system. you do this by removing the thermostat and replacing the housing and run water from the outlet side of the heater and drain the radiator do this several times until the water runs clear. replace the thermo with a new gasket and close the system, fill it up, start the van, wait for the thermo to open then fill as necessary to get the proper level of coolant. hope this helped

Thanks. I actually reversed the whole system as you say, but my heater core is so old that it actually made my heater work a little better but not enough to warm the interior of my car. So right now I am in the process of replacing the heater core. It worked for a friend, who just told me about this, and he got 100% good heat back into his van. Let's see what happens to mine.

By the way, how many lines does the temperature gauge of your Aerostar go up when the motor is already warmed up ? Mine goes just slightly above the first line. I checked the temperature sensor with boiling water and it is OK. Thx.

[mastermech]

your idea could work, it depends on how much scale is built up. I've never had to replace a core to get the heat through, just leaks. You were wondering about the lines on the gauge ford usually has their gauges read 1/3 to a just below the halfway mark. if you aren't getting it properly warmed up, then that is the major reason for not enough heat (yes a car can be over cooled) check and replace the thermostat as necessary. If I recall right the operating temp is 192F for your vehicle.

[RESTREC]

Originally Posted by mastermech

your idea could work, it depends on how much scale is built up. I've never had to replace a core to get the heat through, just leaks. You were wondering about the lines on the gauge ford usually has their gauges read 1/3 to a just below the halfway mark. if you aren't getting it properly warmed up, then that is the major reason for not enough heat (yes a car can be over cooled) check and replace the thermostat as necessary. If I recall right the operating temp is 192F for your vehicle.

Exactly as you said. I took the thermostat out and there it was in front of my eyes: a stuck open thermo. Couldn't believe it. I forced it with a screwdriver from underneath and "click" the middle copper rod in the thermo sat in its place again. How does this happen ? I don't know. Must be a deffect from the manufacturer. I can't understand how the pressure of the water can do this. The spring which holds this rod is strong. o.k. Nevertheless I put a new thermo and THERE YOU GO ! I not only got good warm air inside my car but the temperature gauge is now showing 3 lines up.

I hadn't blame the thermo because I had the false appreciation that even though a thermo would get stuck open, the motor would get inevitably hot after 1/2 hour at least of running. But the case is that water, somewhat warm passing thru the always open thermo, will meet the cooling effect of the radiator system and will never have a chance of getting really hot. Not even in summer. It is that simple. In a Caravan I had I solved the problem of lack of heat inside the car changing the heater core, as I told you. Probably in that particular case, the h. core was bad and the thermo was good. The proof is I never had to change the thermo.

But in this case we are talking about I went on and replace the heater core with no success, and it wasn't until I changed the thermo that I got warm air inside and a healthy warm motor now that winter is coming. Thanks again my friend and hope this helps all readers understand this better. The old thermo is now hanging from my rear view mirror, just to always remember and chat about this case.

[mastermech]

glad it worked for ya. as for the thermo maybe it was a defect or age. will be around in the forums answering questions.

[LadyMe]

Well... since his problem is solved maybe you can help me with mine. Water is not flowing into my heater core from my radiator. That hose doesn't even get hot. It's just not flowing into the unit. I know this because I disconnected the hoses, turned my truck on, let it warm up, and still no water flows through the hose toward my heater core.

I have flushed it the heater core (it was basically clean)... and installed a new thermo, new water pump, new radiator, new radiator hoses, the belt is on right, put on a new radiator cap. I have even taken off the radiator cap and blown into the hoses - they are all clear because the coolant in my radiator bubbles over from the air coming through the hose(s). Lastly, I have been able to blow air through the heater valve. I'm stumped. What am I missing???

I'm restoring a 1981 Toyota Pickup - I even have the original repair manual and STILL I cannot find a solution.

[aleekat]

sounds like trapped air in the system. Park it uphill, take the cap off and run it. System needs "burping".

[LadyMe]

So... you know the part where I said I checked all the hoses... well apparently I was mistaken. ...but on the plus side - at least I know what's wrong.

I was attempting to "burp" the system as you suggested and I was still getting nowhere... so I decided to pull the hose that feeds the fluid back into the engine, and bingo, that thing was clogged in the worse way. Clearing the hose was easy but the "nipple" it attaches to was also clogged. I spent the last of the daylight hours trying to clear it. I got A LOT of nasty out of it but not enough to get the fluid to flow out. This nipple is in a terrible location: back of the engine and low (if I were to pay a garage to clear it - they'd probably tell me they'd need to remove the engine block to get to it but I'm sure there is simpler way).

Since I was out of daylight (and I have no garage) I did the only thing I could think to do. I put the hose back on and filled it with CLR so it can soak into the clot overnight. The only other thing I can think to do is to get a small plumbers snake.

I really appreciate you taking the time to assist me with my problem. I wanted to update you on my progress and also check to see if you (or anyone else) has a suggestion for how I can clear this "nipple" tomorrow if the CLR doesn't do what I hope it will.

Cheers!

[aleekat]

If the nipple you are referring to is on the firewall. That is one side of the heater core. I wouldn't run anything up it in fear of damaging the heater core and causing it to leak. Not sure if the CLR may be too caustic for the core. Hopefully not. Just a guess that a previous owner either put in some "stopleak" or woefully neglected the cooling system. If you get heat back and start smelling coolant or windows fog up running defrost, then you core has a leak.

[LadyMe]

I probably shouldla given more detail... the clogged nipple is on the back of my engine and toward the bottom (and doesn't connect to the firewall anywhere) - The hose runs from the heater valve mechanism down into the engine; completing the loop so coolant can recirculate... and that's where it got gummed up. I'm pretty sure the coolant system was woefully neglected. The truck sat for awhile too before I rescued it. Don't even get me started on how they rigged the carburetor to work (among other things)... but the engine sounds so good - this pickup just needs some TLC and a little blood sacrifice (provided by my father yesterday), lol.

Thanks again - I appreciate you!

[LadyMe]

UPDATE: I'm happy to say that I have successfully cleared the clog from the back of my engine and coolant is finally fully circulating through all the hoses system. As a bonus, I am no longer have issues with my overflow holding coolant hostage - everything is working as it should be. Yay!

Well... the heater still doesn't work but I"m happy to have the clog cleared and the fluids flowing correctly. One problem at a time. Thanks for your assistance. Cheers!

[aleekat]

No heat or blower motor doesn't work??

[LadyMe]

No heat but the blower works.

[aleekat]

I would run it to normal temps with heater on max. Feel both heater core hoses. They both should be hot.