No heat coming from defroster

[alex.t]

I have been trying to get the defroster/heater working so it will be more "comfortable" for the wife. My Chilton manual has nothing on the heating system. Got the fan working, reconnected the vacuum for the switches, now I need the warmth. The Wagoneer has a Buick 350. One heater hose is being run from the water pump to the heater core, the other hose is coming from the top of the intake manifold. One of the hoses going to the core and is getting warm, however, the other hose stays cold. I was able to blow air through the core( lung powered). With the heater core disconnected, I was able to blow air through one end of the heater lines and have water come out the other end. So I have concluded that there are no blockages. Any help would be appreciated.

[PlumCrazyChris]

Check the flapper in the heater box, if its not opening, the heats not getting in the truck. I guess if you have had the heater core out, you've probably checked that already.

I would flush the whole system with some CLR (lime remover) or some other commercial flush and make sure there is no blockages in the system. If one hose is not getting hot, its not flowing. If the hose that leaves the core and goes back into the intake is cold, the heater core is stopped up for some reason. Thats where I would start.

[andy d]

is the thermostat stuck open or missing?

[timmirvin]

How warm is warm? Make sure entry and exit hose is hot, engine temperature hot. That in itself can tell you alot....possible blockage, proper thermostat operation. If the thermostat is missing then the engine may run considerably cooler. And did you check the flapper door, as PlumCrazy suggested??

Tim

[jeepguzzi]

You may also have leaves, pine needles and debris in the heater core box. This will keep air from circulating through the core.

Most likely, though is that the heater core itself is blocked.

[timmirvin]

jeepguzzi.....that is a heak of a signature block!!!!!!! :D :D

[jeepguzzi]

Originally posted by timmirvin:
jeepguzzi.....that is a heak of a signature block!!!!!!! :D :D HEHEHE Yes, I should update it to include the latest upgrades and additions!!

[oldyeller]

My Jeep has no heat at all! the heating unit got stolen before the truck was in my possesion. Ski gloves and layers are warmer anyway!

[timmirvin]

Originally posted by oldyeller:
My Jeep has no heat at all! the heating unit got stolen before the truck was in my possesion. Ski gloves and layers are warmer anyway!Id it just the heater core, or the WHOLE shebang????? :confused: :mad: :confused:

[Mud Thrasher]

That's alright I'll take the heat anyday. Mine gets so hot after a while i have to turn it off.

[JeepBountyHunter]

If the other hose stays cold, is the waterpump not circulating???

[oldyeller]

The whole unit got stolen out of it before i bought it, there is no fan or anything.

[ohiobowhunter75]

My heater core was shot in my wag.I could remove the exit hose and and had good flow but no heat.It can be plugged and still have flow,but just running in the tank and out.I replaced mine and it will run you out now.

[timmirvin]

Originally posted by chiefwidetrack:
If the other hose stays cold, is the waterpump not circulating???To the best of my knowledge....... YEP. :(

Well, let's just say it is not circulating, but not necessarily a bad water pump. Could be a clogged heater core. Could be bad water pump.

To check water pump: (on cold engine)take radiator cap off, start engine, check radiator. If coolant is moving thru radiator as soon as you start it up...then the thermostat may be stuck open, or not installed at all. If coolant does not begin moving until engine warms up then the thermostat is opening and the water pump is working.

If water pump is moving coolant thru radiator and you have a hot hose on one side and a cold hose on the other, there is probably a blockage somewhere. You may have an inline valve or you could have a heater core that is stopped up.

Have you had any overheating problems????

[timmirvin]

I sure hope that made sense..... smile.gif

tim

[tbent78]

if one hose is hot and the other is cold, it sounds like you have a blockage in the heater coil or one of the hoses. You could also have a blockage on the engine. That is if the water pump is working. Someone did not add a valve on either hose from the heater coil did they?? I put a valve on mine to make it a little cooler in the summer.

[alex.t]

I recently replaced the thermostat so I know that is okay. I used the wifes candy thermometer and stuck it in the radiator and let her idle(the waggie not the wife). After a half an hour the water stayed at 180 degrees. Checked hose temperature again and the return seemed to warm up. I think it may be working now. Maybe blowing it out helped some. There may still be partial blockage in the core because it didn't seem to blow as hot as some of the posts indicate it should. I'm thinking it is not flowing through out the whole heater core. Thanks for the help.

[Mud Thrasher]

If you want to try and clean it out some you can try this. Take the hose off going to intake.(this keeps any trash from going in your system). Kink the hose and point it away from you and in a safe place. Have someone bump the engine for you to build up some pressure a few times and then unkink the hose and see what comes out. If you get something out then keep doing it until its all clear and reconnect see what it does then.

[timmirvin]

HHMMMMMMMM......Cajun Ingenuity!!!!!

:D :D :D

[Mud Thrasher]

lol yes sir e bob. You can do the same except us a water hose instead of the motor to pressure it up

[Crazy_Jeepman]

If the Hoses are at different Temps the heater core is Plugged Up. If the hoses are the same temp and you get air in the cab, but not warm then either the Temp control cable, or flapper door is not working as it should. Also the Airflow through the heater core could be blocked. Use a Garden hose to flush a heater core. Water pump on engine does not create enough pressure to do the job just by "Bumping" it. 32 year old rig I would just save a bunch of trouble and replace the heater core. That way its new and clean, and gives you a chance to clean out the heater box! ;)