No heat part 2, I have the core out, need advice fast!

[NHMike]

Ok, I have the heater core out. It doesn't leak and looks to be, in generally, good condition. I'm not getting any heat. Blower works fine and pushes a vast amount of air.

Do I need a new core if it's not leaking? Is there some other problem I'm missing? The doors inside the air box move as they should. The inlet and outlet tubes to and from the Core, have warm water flowing through them.

I'd rather not buy a new Core if I don't need it. Could the core be clogged? I flushed it, and it appears as though liquid is going throughout it.

Thanks!

 

[gert]

well you answered the question I had, the first thing I would be checking is water going thru the core which i would check with a water hose to see what kinda flow I was getting. If in doubt check your local radiator shops and see about getting it flushed out

 

[Old Dog]

The water flowing should be the same temp as the engine ie. 195* does it feel that hot? the heater core should be the same temp., if not than for some reason the water is not flowing right. Maybe the hose or the core is plugged. If it is that hot than the problem has to be in the door system.

 

[ThisGuyUKnow]

If water flows through the core. the flappers all.....um flaptuate, and the blower blows and he box isnt clogged then that pretty much eliminates any problems from the cab side of the fire wall...

You are 100 percent sure that water is flowing through the core freely? The inlet hose should honestly feel hot to the touch not warm. The coolant inside is the same temp as the engine.

So keep following the system back. The inlet on your heater core is fed from the rear of the intake the intake is fed from the water pump in the front. The outlet runs to inlet on the water pump. I start at the latter, see if your return hose is clogged or pinched off then check the inlet hoses to the intake, maybe run a hose through the intake coolant ports to see if maybe it is clogged. IF everything seems to check out and flow freely then maybe your water pump isnt pumping?

EDIT: Actually now that I think about it isn't the outlet side of the water pump in the T-stat housing? If my memory is correct then the Tstat has to open up before you will get coolant moving through the hoses. Are you allowing the jeep to heat up to operating temp before testing for heat? If so is your Rad heating up, Maybe your T-stat is stuck closed. Or maybe it is stuck open and the radiator is keeping the coolant from heating up?

Just thinking aloud

 

[NHMike]

Thanks guys.

I've got the Core out, going to pick up the new one tomorrow as well as a thermostat. I'm thinking the core bust be clogged up.

I'll let ya's know if it works. Thanks!

 

[ThisGuyUKnow]

Thanks guys.

I've got the Core out, going to pick up the new one tomorrow as well as a thermostat. I'm thinking the core bust be clogged up.

I'll let ya's know if it works. Thanks!

Im telling you, while you got it all apart you really ought to just bite the bullet and put in the blazer blower motor you wont regret it. and you already got everything torn apart

 

[Supertrunk]

If everything else checks out OK, take a look at your water pump. At least on my 81 CJ7 it turns out there are TWO pumps available. One spins one direction for V belts. The other one spins the opposite direction for flat serpentine belts.






Want to take a guess how I found out about this..................?
Hope this helps.

 

[gert]

If everything else checks out OK, take a look at your water pump. At least on my 81 CJ7 it turns out there are TWO pumps available. One spins one direction for V belts. The other one spins the opposite direction for flat serpentine belts.






Want to take a guess how I found out about this..................?
Hope this helps.

lol that must have sucked

 

[danray48]

I'd rather not buy a new Core if I don't need it. Could the core be clogged? I flushed it, and it appears as though liquid is going throughout it.


Read more: http://www.jeep-cj.com/forums/f49/n...ore-out-need-advice-fast-20714/#ixzz2lBSuvPYd

Process of elimination. Either water is flowing through the core or not. Since the core is out and water does flow through it, move on to hoses which should be easy to check. It sounds like either the pump is not working correctly because it's bad, or you have a bad thermostat that is allowing just enough water to bypass to the core which would just be warm, not hot. Not knowing for sure, but just a thought, I would think that water should not flow through the core fast allowing the cooler blower air to absorb heat from the hot core. If it ran through fast, it wouldn't have time to remove the heat from the water. Just my HVAC experience kicking in.

 

[SlowPocono]

I'd rather not buy a new Core if I don't need it. Could the core be clogged? I flushed it, and it appears as though liquid is going throughout it.


Read more: http://www.jeep-cj.com/forums/f49/n...ore-out-need-advice-fast-20714/#ixzz2lBSuvPYd

...Not knowing for sure, but just a thought, I would think that water should not flow through the core fast allowing the cooler blower air to absorb heat from the hot core. If it ran through fast, it wouldn't have time to remove the heat from the water...

That would be important if the object were to cool the water but in this case the small, fixed volume of the heater core just needs to pick up heat from the flowing coolant. The velocity needs to be greater than the core's capability of cooling it.

 

[Sam5038]

I had a 82 CJ8 with the AMC 258 i6 / 4.2l I-6. When I ran low on water in the radiator it would develop a air bubble in the heater core. Even if I toped off the radiator, I still couldn't get heat out of it. To fix this. I had to loosen the heater hose while the motor was running to let the air out.

 

[7D8CJ]

If everything else checks out OK, take a look at your water pump. At least on my 81 CJ7 it turns out there are TWO pumps available. One spins one direction for V belts. The other one spins the opposite direction for flat serpentine belts.






Want to take a guess how I found out about this..................?
Hope this helps.

Seen it. The core can be partially plugged and still appear to flow. Replace it and the t stat if you haven't already. Water pump not spinning will also overheat the engine. Spinning in the wrong direction should only be an issue if you just replaced it. You should have heat before the stat opens. Coolant circulates though the eng. and heater core only when the eng. is cold. When the stat opens then it passes though the radiator for cooling. This is why a stuck open stat will cause poor heat.

 

[NHMike]

I had a 82 CJ8 with the AMC 258 i6 / 4.2l I-6. When I ran low on water in the radiator it would develop a air bubble in the heater core. Even if I toped off the radiator, I still couldn't get heat out of it. To fix this. I had to loosen the heater hose while the motor was running to let the air out.

I'll give this a try. Thanks!

I replaced the Core today, as well as the Thermostat and I'm STILL not getting heat. I even drove into work to ensure the motor was getting up to temperature.

HOPEFULLY "burping" the Core will get me some damn heat!

Thanks guys!

 

[NHMike]

Frustration ensues.

There is hot hater flowing into the core no doubt about it. And then, tthere's COLD water coming out. I pulcer off both hoses, while the motor was running (and warm). Is it realistic that the fan cools it SO efficiently that there's only cold air blowing out?


I am stumped.

 

[Hedgehog]

The only thing that can create this situation is to have either no or a malfunctioning thermostate. If the water is cold it shouldn't be getting out of the engine. Water gets warm, the thermostat opens, then closes, when all the water is the system is hot it stays open until it gets cool again. Your radiator water should be hot, if not water isn't circulating the way it should.

 

[SlowPocono]

Frustration ensues.

There is hot hater flowing into the core no doubt about it. And then, tthere's COLD water coming out. I pulcer off both hoses, while the motor was running (and warm). Is it realistic that the fan cools it SO efficiently that there's only cold air blowing out?


I am stumped.

How hot is the water entering the core?
If it isn't hot enough to burn your fingers, then it isn't hot enough.

Have you replaced or removed the thermostat?

 

[ThisGuyUKnow]

I'll give this a try. Thanks!

I replaced the Core today, as well as the Thermostat and I'm STILL not getting heat. I even drove into work to ensure the motor was getting up to temperature.

HOPEFULLY "burping" the Core will get me some damn heat!

Thanks guys!

He replaced the core and the T-stat according to his post. That means that either the new t-stat is backwards or the water pump is bad.

 

[Hedgehog]

Exactly. The way water flows through the heater core and the engine simply isn't that complicated.

 

[74G8R2]

My only suggestion would be to move to Texas where you won't need the heater.

 

[danray48]

Frustration ensues.

There is hot hater flowing into the core no doubt about it. And then, tthere's COLD water coming out. I pulcer off both hoses, while the motor was running (and warm). Is it realistic that the fan cools it SO efficiently that there's only cold air blowing out?


I am stumped.

No, the fan wouldn't cool it that much. and if it did, you would have to have warm air blowing in your cab. You have a new core, so I don't believe the water is "flowing" into the core. If it was, then it would be flowing out warm or hot, and you would have warm air blowing period. If you purged the lines of air, and everything was working, then you should have heat. Your problem is in the thermostat or the pump. Is the T/S in the right way, and is it working? Don't matter if it's new, I deal with new junk parts all the time. Put your T/S in a pan of water on the stove, and see if it opens when it gets hot.