Heater dont work and its COLD in Utah!!!

[Qudawg]

My heater is desperatly not working and I cant figure out why! My coolant is completely full atm, The engine runs at about 175 degrees(i think) My main idea on this is maybe my heater box is clogged with something?? no idea.. when running at normal temperature my rig's upper radiator hose has pressure and is hot to the touch, however the lines going to heater box are only mildy warm. could it be, water pump, or heater box?
thanks :confused:

[6foot4 again]

I'd check fuses as well, Quinn, THEN get to the more expensive parts....

[Rick@battlement]

Have you made any changes to the system since it last worked?

[Mondo Bat.]

Just take out the carpet. smile.gif

Actually, mine did that when I repaired my heatercore, Try flushing the system, problem could be that air is trapped in the core or in the lines, mine repaired itself after about a week of running it (finally pushed out that air bubble.)

[Mondo Bat.]

Oh, and, you gonna buy my jeep or what! smile.gif smile.gif

[243]

First, make sure the heater control cable is moving the flapper at the heater core completely, open and closed.

Check for a water control shut-off valve in the heater supply hose.

Then pull the high pressure water hose off the heater core and see if you have pressure. If you don't, check the fitting at the other end of the hose at the motor and see if it is blocked. If you do have pressure, pull the hose off the low pressure side of the heater core and see if you are getting sufficient return flow.

That should get you started.

[Qudawg]

Originally posted by 243:
First, make sure the heater control cable is moving the flapper at the heater core completely, open and closed.

Check for a water control shut-off valve in the heater supply hose.

Then pull the high pressure water hose off the heater core and see if you have pressure. If you don't, check the fitting at the other end of the hose at the motor and see if it is blocked. If you do have pressure, pull the hose off the low pressure side of the heater core and see if you are getting sufficient return flow.

That should get you started.which one is the high pressure side? the one on the left or right(when looking in engine bay from front of fsj) also, on motor end what one is high pressure? off water pump, or off of manifold?

[Qudawg]

Originally posted by Mondo Bat.:
Oh, and, you gonna buy my jeep or what! smile.gif smile.gif I dont think I can financially right now but I would if i had the $$ I really want one I dont have to work on every otehr weekend and sometimes between

[Rick@battlement]

Who has a jeep like that and drives it?

I dont think I can financially right now but I would if i had the $$ I really want one I dont have to work on every otehr weekend and sometimes between

[Marvin Gates]

You can get a new heater core at Napa for $49, I changed two of them cause they were both plugged and after cleaning them they leaked. Solved the problem heater will run you out now. :D :D :D

[J10Mike]

i agree with 243, check that heater control cable at the heater core box. mine was completely severed. although i didn't replace the cable, i put a wire tie on it during the summer to keep the heat out, and, i recently tied it the other way to get the heat. works for me.

mike

[243]

I can't tell you which direction the coolant flows. But one other item to check is that you have vacuum at the heater/ac control panel. When you switch to heat, the air inlet door directs the air to the floor outlet.

[89Wagoneer]

just to answer the flow direction question, it flows from waterpump to heater than back to backside of block.

[jode]

One other (Cheap) longshot is to check the vacuum controls that open the dampers...you can reach them from under thedash (it aint easy though) they are on the driverside of the gauge cluster (as you know) and there are 3 hoses that stick out there....I had this problem just a few days ago....

[Don S]

..
Qudawg
... The coolant flow in the heater hoses on the 401s is from the rear of the engine to the core then to the feed side of the water pump. It is important to NOT block this flow.

Good Luck.. http://www.boylover.net/ubb/graemlins/cool_shades.gifand CUL.. Don S..

[89Wagoneer]

you can check for flow rate by disconecting the heater lines at the block and pump and run a garden hose to one of the lines if you get alot of water out the outher end it works if you don't get alot of water it is clooged in some way.

[Qudawg]

I checked my vacuum lines for damper operation, they work fine. I also checked the cable that changes from hot to cold that was in good operation also, BUT this could be the culprit.. I switched from stock intake to a 4 barrel intake off a 401.. maybe that is the problem? Im thinking so but my stock heater hose lines hooked up in the same locations.
thanks