flushing a heater core

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jwh70valiant

jwh70valiant

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Recently, as it got cold hear, I learned my car does not have heat. I checked the heater core, which wasn't leaking, and checked to make sure that the vents opened up properly, which they did. I figure there must be something stopping up the heater core causing it to not circulate antifreeze. I know I am going to have to flush it; What is the best way to go about doing this? Normally I wouldn't be that concerned, but it is 25 degrees where I'm at with snow on the ground, so hooking up a hose and flushing it ouside right now is not a good option.

Thanks
 
Does your car have a heater control valve in one hose?

Are the hoses getting hot?

Are you sure the car is not low on coolant?

Could also be a water pump impeller broken loose from the shaft--ask me how I know

Is there a reason--looking in the filler neck--that you suspect the system is that dirty?
 
yea do all that he says, and if not I'de just go get a new heater core, mine was $25 at advanced and they had it in stock
 
No the car does not have a heater control valve on the hoses. One hose gets hot while the other stays ice cold. I just replaced the water pump, so that shouldn't be it. The reason I think it is stopped up is because when I got the car several months ago, there were mouse nests and leaves every in the car, due to it sitting. Due to the heater core getting coolant and not leaking makes me think that it was still good, but something is stopping it up. I'll check into getting a new one; that sounds the easiest route to take.
 
Well I would not run out and buy a new core. Mouse junk/n stuff should not stop up the core, unless you are talking about the outside part of the core.

flushing is easy---just identify the hoses for flow, and run water through it BACKWARDS from a garden hose
 
why not just swap hoses going into firewall and reverse flow through heater core and maybe dislodge any obstruction
 
red67gts said:
why not just swap hoses going into firewall and reverse flow through heater core and maybe dislodge any obstruction
Click to expand...

Heh.....if there IS junk in the core, why would you want to flush it right back into the engine?

Speaking of which, if the core IS internally plugged, you should flush the engine too
 
The warm hose is the SUPPLY hose. The cold hose is the RETURN hose. Simply remove the return hose from the engine, duct tape a garden hose on it real good. Then remove the supply hose from the engine and hang it over the fender. Turn the garden hose on full blast. Liquid plumbr works good too. Sometimes you run into really stubborn clogs. Just dump some Liquid Plumbr into the upper most hose and let it sit a little while and then flush as outlined above. Works good. The Ford Taurus and Mercury Sable cars were really bad about doin that when I worked for Ford. That's how we used to clean um out. Saved our customers big bucks because the whole dash has to come outta those cars for a heater core replacement.
 
reason I suggested that was a friend had put black pepper in radiator of his welding truck to stop leak but when winter came his heater wouldnot work so swapped hoses and heater started back working. I put some liquid glass in radiator not long ago and stopped it up so I used a trick I learned from running heavy equipment and put Tide detergent and it cleaned it right out. I used the liquid for my front loading washer that doesn't suds as much
 
I pulled the heatercore :( It was choked full of rust and debris; no wonder it didn't work properly. I am ordering a new one. Thanks for the advice guys!
 
StrokerScamp said:
The warm hose is the SUPPLY hose. The cold hose is the RETURN hose. Simply remove the return hose from the engine, duct tape a garden hose on it real good. Then remove the supply hose from the engine and hang it over the fender. Turn the garden hose on full blast. Liquid plumbr works good too. Sometimes you run into really stubborn clogs. Just dump some Liquid Plumbr into the upper most hose and let it sit a little while and then flush as outlined above. Works good. The Ford Taurus and Mercury Sable cars were really bad about doin that when I worked for Ford. That's how we used to clean um out. Saved our customers big bucks because the whole dash has to come outta those cars for a heater core replacement.
Click to expand...
Strokerscamp you really are a fountain of knowledge, my son has a Taurus and the heater core was plugged in it and unfortuantly I tried everything to clean it except the drano trick, I ended up replacing the heater core, Fortunatly he has a 98 taurus and you dont have to remove the dash on 97 and up so it wasn't too bad of a job, Has anyone asked if the thermostat has been replaced lately???
 
I just replaced the thermostat about two months ago, along with the temperature sending unit. I brought the heatercore in the house and flushed all the rust and other debris out. It still isn't leaking.
 
jwh70valiant said:
I just replaced the thermostat about two months ago, along with the temperature sending unit. I brought the heatercore in the house and flushed all the rust and other debris out. It still isn't leaking.
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Does it seem to flow out as fast as it goes in?? the one we had on the taurus would not put out hardly any water no matter what we tried, except I never thought about the Drano thing, did you order a new one or are you gonna try this one?? The one I have in my duster is original and as of last week it was working fine, 36 years young, of course now I jinxed myself and it will start leaking now....
 
knock on wood... it pours out rather slowly. I looked at it further and I found that the intake pipe was cracked at the weld into the core. still, though, when the tube is pressed in it does not leak out the crack, it just dribbles out slowly. I haven't tried the drano trick yet. With the intake pipe cracked, is it worth saving it? I would fix this one then buy new.
 
jwh70valiant said:
knock on wood... it pours out rather slowly. I looked at it further and I found that the intake pipe was cracked at the weld into the core. still, though, when the tube is pressed in it does not leak out the crack, it just dribbles out slowly. I haven't tried the drano trick yet. With the intake pipe cracked, is it worth saving it? I would fix this one then buy new.
Click to expand...
If I am not mistaken the old ones in our cars should be copper and you can solder that crack shut with a propane torch, It's worth a try, make sure you use plumbers solder and use alot of flux.
 
Everyone does things differently. I drape both heater hoses over the fender and switch the clear water supply direction repeatedly until the outbound runs clear.
I wont over attach the water supply ( garden hose ) to any part of a vehicle cooling system. Average pressure of public water is 65 p.s.i.
A lot more than the parts were rated for .
 
I agree with redfish... flush the darn thing with your garden hose and flush in both directions. You'll probably find lots of crud coming out so keep on flushing and get it all out. If no water comes out then it's totally plugged and probably time for a new core.

good luck
 
412 Stroker said:
Strokerscamp you really are a fountain of knowledge, my son has a Taurus and the heater core was plugged in it and unfortuantly I tried everything to clean it except the drano trick, I ended up replacing the heater core, Fortunatly he has a 98 taurus and you dont have to remove the dash on 97 and up so it wasn't too bad of a job, Has anyone asked if the thermostat has been replaced lately???
Click to expand...

They also use a bypass hose on the older Taurus, like 97 - 99 model years. If the core is even slightly clogged, coolant will flow throught the bypass and not even go to the heater core. Make sure you pinch the bypass hose if you are flushing out one of those FERD cars.
 
RedFish said:
Everyone does things differently. I drape both heater hoses over the fender and switch the clear water supply direction repeatedly until the outbound runs clear.
I wont over attach the water supply ( garden hose ) to any part of a vehicle cooling system. Average pressure of public water is 65 p.s.i.
A lot more than the parts were rated for .
Click to expand...

And that's good advice. I left out the part about not turnin it wide open. Sometimes I take for granted people will figure it out on their own. They might not. Thanks.
 
Well, I removed the core, and flushed it out with an air hose - and found all kinds of crap. I hooked it back up. I didn't drive the car 1000 feet before steam started pouring into the car. I got the car home, let it cool down and removed the outlet hose off of the water pump. It was packed full of crap. Tomarrow, I'm going to see if that drano trick might work to clean out the blockage.




I hate living in ohio with an older car and no garage in the winter!
 
Once you get it fixed...the key from here on out is REGULAR coolin system maintainance.
 
jwh70valiant said:
I pulled the heatercore :( It was choked full of rust and debris; no wonder it didn't work properly. I am ordering a new one. Thanks for the advice guys!
Click to expand...
What happened to the new one? If you're doing all of that work to get the old one "working", just put a new one in. When it gets REALLY cold, you'll be glad you did.
 
update:
This poor car was mistreated for a long long time. I flushed the cooling system and took the water pump apart. The water pump was so chocked full of crap, it amazes me that it even turned! For now, I am bypassing the heatercore, as I decided to forgo getting a new one. ( i had to make an unexpected long trip and need the gas money).

After idling, it would start steaming hot anitfreeze out of the intake line going into the core (coming off of the block). Then the inside of the car filled up with steam and we have a problem :(

I am still amazed at how much crap this car has taken over the last 41 years, 310,000 miles, 10 years in a junkyard and it still runs! I got the car seven months ago, and the last time it had an oil change was 1977. that first oil change was a mess!
 
You should remove the drains at the bottom of the block on each side. If nothing comes out, stick a screwdriver in there and free up all the crud.
 
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