2000 XJ No Heat Blend Door Question

[dumbagain]

2000 XJ

blows cold air

both heater core hoses in & out feel pretty hot to me

when i turn cold to hot i can see the blend motor turn (doesnt necessarily mean its moving door right?)

fan motor know only blows on 4 also


if its not the heater core (which it probably isnt because both hoses hot right?) then how do i expose the blend door to inspect what its doing?

read something about foam insulation wearing out also?

help its getting cold

 

[CharlesS]

The fact that the fan only blows on position 4 indicates that more than likely the blower resistor has gone bad. The resistor is under the dash near the glove box.
If both heater lines are hot no heat is being picked up by the air as it goes thru the core. This can be caused by the malfunction of the blend door as you indicated previously.
Keep us informed on what you find.

 

[dumbagain]

looked into problem yesterday...

heater blower motor fixed the fan motor problem of only working while on 4 full blast.

took blend door motor off. it turns freely, is still greased up inside, and moves the full distance.

blend door moves freely by hand, doesnt seem loose or anything. tested it by turning it by hand. the cold air got a little warmer but still nothing like it should be.

went to feel the heater hoses again. this time i felt a considerable difference. the top one coming out of the thermostat housing was hotter.
BAD HEATER CORE

gonna switch the heater hoses and drive a little and see what happens.....

 

[ktwalker01]

You can always stick a garden hose on the heater core output and back flush the system, I've done this by switching the hose from pipe to pipe over and over many times to agitate and free up blockages within the core.


I have a 99, only working on 4 is the blower resistor failure.

I had the blend door actuator fail on me for the heater and i took the thing apart had to turn the motor by hand to "free it up" and then sprayed it with some crc electric cleaner. taking that little assembly apart and putting it back together isn't a science unless you fiddle with the other components inside of it...

The foam failing will cause the heater to be mute as well.. I figured this out after having my hvac box out and replacing the evap core and never replacing the insulation for either cores.. i'm an idiot for this one.

 

[dumbagain]

flushed out heater core in reverse direction, lot of sediment and black crap came out, flow seemed unrestricted. reversed it and more sediment came out. filled the heater core with vinegar and water and let soak overnight then flushed it again with even a little more crap flowing out.

heat seems to be working now! need to flush the whole system it seems and get some new fluid in there.
what causes the coolant to become so rusty looking?
are the power flushes that say a valvoline oil change provide worth a try?