flushing a heater core

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Newbie question: What is the best way to bypass the heatercore?

Initially, when I pulled the heatercore, I blocked both the hoses. This resulted in too much pressure building up and the radiator hose blowing. So, after I found a blockage in the system and cleaned it out, I took the intlet hose off and took the return hose, coming from the water pump, looped it around and hooked it into the manifold. This seems to work, but there is still a light antifreeze leak coming off of the connection at the manifold. I figure this might be because the return hose is slightly larger than the sending hose. I know this isn't the greatest fix in the world, but will this do any damage to my car? Any suggestions?
 
A couple more twists on the clamp will solve your problem...temporarily. Sounds like you need a new heater core. When you are ready, I would buy some radiator flush and run it through per the directions. Replace all the hoses and thermo when you do the heater core and you should be fine.
 
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.
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Good idea. I use clr in them. Not quite as corrosive. Pinholes are a *****. I just recconnected the hoses to my heater core in my beater s10 cause the core leaks and put a big can of bars leak in it. It's not running hot and I'm warm and I don't care what it f,s up as long as it lasts till spring.
 
Not meaning to hijack, but I need info.
Reading this makes me think my hoses are hooked up backward. Can someone tell me, Which hose is inlet? One from waterpump? My heatercore is new but low in the heat department. It does blow slightly warm air.
 
red67gts said:
why not just swap hoses going into firewall and reverse flow through heater core and maybe dislodge any obstruction
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And plug up the coolant passages in the engine.

flush the core by putting water into that hose that stays cold. That will be the direction opposite of the way it flows through the system.

EDIT: I should have read the whole thread before posting that.

HEMIPAR: technically it does not matter which way the coolant flows through the heater core. You can switch the hoses around and it will work the same. It sounds like you have a bad thermostat.
 
HemiPar said:
My heatercore is new but low in the heat department. It does blow slightly warm air.
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First make sure you have the right thermostat. If a low-temperature thermostat was installed, get the specified one. The direction of flow shouldn't matter.
 
Also, if your hoses are not the same size, you can usually tell if they are not hooked up right. You can run the coolant through in either direction, but may get some leakage if you have a big hose on a small nipple (that didn't sound right). Check that your heater core is sealed up (no gaps or cracks to let cold air into the plenum) and also that all the doors are open to let the heat into the car. Also, if you have a new core, but used the old hoses, they may have "swelled" inward and reduced the diameter and flow. If you haven't flushed your cooling system in a while, you may have crud restricting flow.
 
I sealed off the leak with my bypass hose. I ran the car for a little bit, drove it around town. By the time i got back, steam was pouring out through the overflow hose. I do not have an overflow tank. Suprisingly, the car does not seem to be leaking any coolant.

I am thinking this means the radiator is shot.
 
May not be shot, you may have just plugged it with crud from the heater core. Try flushing the radiator.
 
Or for that matter, the thermostat,waterpump, or passages could be clogged. Your engine may just need an enema to get everything cleaned out.
 
4flats said:
Or for that matter, the thermostat,waterpump, or passages could be clogged. Your engine may just need an enema to get everything cleaned out.
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I second this.....especially if somebody has been using stop leak in it like an idiot. That stuff could stop up a two dollar *****.
 
lol

As a matter of fact, it didn't hit me until you just said it, but i found three, big empty bottles of stopleak in the trunk when I bought the car. :banghead:

Hmmm that probably explains why my heatercore got stopped up and now the radiator pouring steam out of the radiator.

Someone suggested that the thermostat may be causing this. I am sure that stop leak could have jammed my thermostat shut, too.

I wonder if stopleak ruins waterpumps. I ran the car today without the radiator cap on to see if I could see flow and the coolant in the radiator remained stagnat. I put the cap on, ran the car for a few minutes, took it off and found the same thing.

Thanks for all the help guys!
 
After finding ice in the radiator, I took the hoses off, and brought the radiator inside my house to thaw out. ( I wish I had thought of this sooner, as I do not have a garage.) I flushed out the block and water pump and flushed the radiator out in my bath tub. I also stopped up the bottom hose opening and filled it with water to check for leaks. It didn't leak.

I removed the thermostat and boiled it. It barely opened around 230 degrees, and I found plenty of stop leak inside of it. So I got a new thermostat to replace it and plan on re installing the radiator and hoses tomarrow.

Why would it start spewing steam out of the overflow after I removed the heater core? ( It didn't do this before) Also, should a new thermostat and new antifreeze solve the problem?

As to the ice in the radiator, there was no ice in the block, and I drained the coolant out of the block just to make sure I didn't have an expensive disaster.

Thanks
 
I flushed the radiator filled it with antifreeze, hooked everythign up and started her up. Took her for a little test drive, and no more over heating!
 
Congrats. seams like the stop leak clogged more than just a hole.
 
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