Heater Core Replacement - The Missing Steps

[lorraine1]

mine was a little different except for the wire hook ups or plug ins,they tell me each one is a little different from the other.

 

[skydude]

Heater core issue?

Hi guys.
Question from a Norwegian here; I've had the pin-in-actuator (for the blend door) fix on my 98 Explorer (4L SOHC, 4x4) for a few years now but as it started getting cold last year, I couldn't get any heat from my ventilation system. I just assumed that the temporary fix had seen the end of its days so I moved along in the forum and found and did the blend door (Rock Auto) replacement through the bottom of the plenum. Before I sealed off the bottom I made sure that the new door worked, being able to see through the cracks.
However I am not getting any heat! I still seems like the door turns around its pivotpoint when I adjust the temperature (sound/tactile indications), there is no leak from underneath the plenum and the entire plenum is not getting warm at all... Any suggestions would be much appreciated. Chris

 

[koda2000]

Are both heater hoses in the engine compartment getting hot? If not it may be that your heater control valve is not working, or that your heater core is clogged. Have you verified that your engine is getting up to full operating temp (around 195 degrees F)? If not you may need to replace your thermostat. Are your HVAC directional controls working (VENT, FLOOR, DEFROST)? If not you may have a vacuum leak which is preventing the heater control valve (which is vacuum actuated) from opening. When you loose vacuum the air will only come out of the defroster vents.

 

[skydude]

Wow, that was quick, thanks! I am getting air from the different vents as I turn the direction knob so that's one issue eliminated. Tempereture gage is showing normal operating temperatures, but whether these are true or not, don't know...I'll get the truck out one of these days and check the remaining potential culprits. Thanks again !

 

[skydude]

Feeling a bit stupid

It's only 15-20 degrees F here now so I have been reluctant to do any troubleshooting. But after reading a bit I decided to top off on the coolant even though the fluid level in the expansion tank was steady. As I neared 4qts! I was beginning to see the fluid through the filler hole but unfortunately the fluid started seeping out through a crack at the radiator/body attachment point! So I guess as the fluid gets warmer it escapes through that crack and neither expansion tank nor heater core gets any fluid...- or the problem for the latter is all the air in the system?? The vent air in the cab is still cold even after all this and the hoses through the firewall are only marginally luke warm.
---------
- 2 days later: of course, replacing the radiator did the trick! So now I have a new and improved blend door and a "new" radiator to carry me through the winter

 

[richardcooper]

Thank You.This is very helpful.
Did you have to do anything with the A/C system? Drain system and refill?

 

[ttbit]

Thank You.This is very helpful.
Did you have to do anything with the A/C system? Drain system and refill?

I did not.

 

[Fredness]

Is this being accessed from the engine compartment or the passenger airbag area?

 

[ttbit]

Is this being accessed from the engine compartment or the passenger airbag area?

Which part? You need to get access to both areas to remove it.

 

[Fredness]

I saw a video on YouTube about going in from the Airbag area - without touching the A/C Plenum.

 

[ttbit]

Oh...OK. My AC was already empty, so I didn't have to worry about it. I think you can get by. 99% of the work is inside the vehicle. It is a major job.