heater core

Jeep444 · 10-27-2005, 03:02 AM

Hello all,
I am having a problem with my 97 jeep wranglers heater core.I think it needs to be replaced or flushed out,all I get it cold air.My water pump blew about a week before and since the replacment of that my heater only blows cold air. My problem is that i'm not sure where the heater core is located and how big of a job it is to replace. Can anyone help,pictures would also be a great help if anyone has any.
Thanks
Jeep444

btolle · 10-27-2005, 05:45 AM

I doubt that the heater core is the problem. If the heater was working before the water pump was replaced I suspect that something is not properly connected, such as the vacuum line for the heater controls.

The vacuum line for the heater controls may have been pulled loose while changing the water pump. Try changing the settings on the A/C controls and see if the air shifts from the dash vents to the floor vents to the defroster vents. If changing the control from heat to vent to defrost makes no change in which vents the air is coming out of the vacuum line is disconnected.

If that is not it then:

According to the FSM for a 2004:

Both of the heater hoses should be HOT to the touch (coolant return hose should be slightly cooler than the supply hose. If the coolant return hose is much cooler than the supply hose, locate and repair the engine coolant flow obstruction in the heater system.

If both heater hoses are cool to the touch, inspect the engine cooling system.

OBSTRUCTED COOLANT FLOW Possible locations or causes of obstructed coolant flow are as follows:

Pinched or kinked heater hoses.
Improper heater hose routing.
Plugged heater hoses or supply and return ports at the cooling system connections.
Plugged heater core.

If proper coolant flow through the cooling system is verified, and heater outlet air temperature is insufficient, a mechanical problem may exist.

MECHANICAL PROBLEMS Possible causes of insufficient heat due to mechanical problems are as follows:

Obstructed cowl air intake.
Obstructed heater system outlets.
Blend-air door not functioning properly.

TEMPERATURE CONTROL
If the heater outlet air temperature cannot be adjusted with the temperature control knob on the A/C-heater control panel, the following could require service:
Blend-air door binding.
Faulty blend-air door motor.
Faulty A/C-heater control.
Faulty related wiring harness or connectors.
Improper engine coolant temperature.
-----------------------------------------------------------

You did not use Barsleak or some other radiator additive did you? I have seen some of that stuff that stops up heater cores.

Bill Tolle
05 Rubicon
04 Liberty

If you love offroading and want the trails to stay open please join Blueribbon Coalition.
"Preserving our natural resources FOR the public instead of FROM the public"
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Jeep444 · 10-27-2005, 05:43 PM

The vacume line is not disconnected but when I have the heater on full the lines going into the firewall (heater core) are cold,both of them,there are bo bent hoses anywhere that I can find no leaks.Everything seems to be as it was before I lost heat.The heater core is an OEM product for 217.00 I can get one of thoes for 45.00 at a local junk yard (if I have to) That is if it is even the heater core at all. I just don't know,I'm going to take another look around the engine again tomorrow,just to double check. If there is any other advice anyone can give I would be greatful.
Jeep444

KURTS4X4 · 10-27-2005, 05:51 PM

Did you check to see if your engine is coming up to temperature ( 200+/_). If not you might need to replace your thermostat.

Jeep444 · 10-27-2005, 06:28 PM

Yuppers,That was the first thing I checked,temp is OK,and I have a new thermostat in.
jeep444

OlllOTJ · 10-27-2005, 06:44 PM

what temp thermostat did you put in? what temp is your engine running at

btolle · 10-27-2005, 06:52 PM

Did you put the water pump on yourself or did somone else do it?

Check to be sure the heater hoses are connected properly. In other words, could they have been reversed when the water pump was intalled? You probably need to look at another Jeep with the same engine you have to see how the hoses are connected.

Before you tackle the heater core I would drain the coolant and pull the heater hoses and be sure there is not a plug or other obstruction.

It makes no sense for the heater to quit working when the water pump was installed unless something was hooked up wrong or there was some type of plug in the new water pump that they did not take out.

Bill Tolle
05 Rubicon
04 Liberty

If you love offroading and want the trails to stay open please join Blueribbon Coalition.
"Preserving our natural resources FOR the public instead of FROM the public"
http://sharetrails.org/

DietCola · 10-27-2005, 06:54 PM

If you get cold air...this wont help. If the air is warm but not warm enough, you may have the same problem I had with my TJ last year.

The heater lever wouldn't go all the way to the right (warm). I have to reach under my dash and manually pull the lever over about 1/4" and now the heat is HOT! I'll try and get pics of the lever I am talking about tomorrow if needed. Just look under the center of the dash from the passenger side while you or someone move the temp lever from cold to hot and you will see the part under the dash move. Try moving it a little more towards the warm side from under the dash. Once you get good, you can do it from the driver's seat.

Jeep444 · 10-27-2005, 08:29 PM

Thanks everyone,I'll take a look at everything again tomorrow.The water pump was installed at the local car dealer.more to follow soon
Jeep444

Jeep444 · 10-28-2005, 10:30 AM

I just took a look around the engine again,All hoses are hooked up the way they should be.My thermostat is a heavy duty superstat made by stant manufacturing for
195 deg F/90 DEG c . I am going to try and pull the hoses off to see if any of them are pluged. thats the only other thing I can think of right now.I didn't look at the Blend-air door because I don't know where it is located as well as the blend-air door motor,anyone know the locations of them.
thanks
Jeep444

**04 Unlimited** · 10-28-2005, 11:09 AM

Air pockets would prevent flow into heater core. And heater inlet hose is quite high, so air would collect there. But, since the cooling system is self purging, assuming you have a full overflow reservoir and the tube entering the overflow reservoir is not blocked, the air should have purged from the system by now. If you disconnect the heater hoses, you should be able to tell if the heater core is blocked by simply blowing through it (don't inhale!). If it's blocked, you'll know right away.

Jeep444 · 10-28-2005, 12:00 PM

well,I think I found the problem.I took off my hoses coming and going to my heater core and blew in one end to see if it was pluged.I found that after blowing as hard as I could alot of metal flakes and some very dark stuff came out the other hose,and no I didn't inhale

I then started my jeep up and let it idle for a few min and I started to get heat again.I hope this puts the problem to an end,all it cost me was the price of some Rad fluid.I always thought that some crap from my water pump had blown up into my heater core but wasn't really sure,guess I know now.

Thanks to all for the helpful advice
Jeep444

scottcha · 10-28-2005, 12:10 PM

As mentioned, with a dead heater core you would have coolant on the passenger side floor. Be glad that it isn't your heater core, they are a royal pain to change.

btolle · 10-28-2005, 04:14 PM

Quote:

Originally Posted by Jeep444

I found that after blowing as hard as I could alot of metal flakes and some very dark stuff came out the other hose

Glad you found the problem. I would consider draining the antifreeze, pull the lower radiator hose loose, take the thermostat out, and flush the system thoroughly with water (with engine running) to get any of the crud that is left out of the system. If you do that be sure the heater is on the hottest setting so the water will flush through the heater core.

Or, at a bare minimum, disconnect both heater hoses and hook a garden hose to the inlet and flush the heater core as thoroughly as possible. I would also flush it again through the outlet hose.

The hazard of not flushing it is that you might get enough crud in the thermostat to block it and overheat the engine.

Bill Tolle
05 Rubicon
04 Liberty

If you love offroading and want the trails to stay open please join Blueribbon Coalition.
"Preserving our natural resources FOR the public instead of FROM the public"
http://sharetrails.org/