Was ready to replace heater core but discovered it was not the leak point

[crunchie_frog]

I had an engine coolant leak coming down underneath the blower / evaporator core housing and dripping on the passenger side inside the wheel well cover. I looked from underneath and all I could see was the bottom the blower / evaporator core housing had coolant dripping from it so I thought it might be a heater core leak somehow even though there was no smell inside the cabin or leaks inside the cabin. I had done this job (heater core replacement) before on a previous 5.0 Mountaineer but re-reviewed several videos and knew all the nuts, bolts and their locations by heart to remove the dash and heater core so I started the job yesterday evening after work, sort of dreading what I was getting into. I started with backing out the blower / evaporator core housing and disconnecting the heater control valve and heater hoses. As I was backing out the blower / evaporator core housing, the plastic end tubing on the firewall side of heater valve gave way and broke into. The blower housing / evaporator core housing insulation was wet under where this plastic tubing was and it looked like it had been leaking down from there and then following the housing around and dropping out on the passenger side. I also looked behind the blower / evaporator housing and could not see any evidence of a leak back inside there where the air flow was or underneath the heater core. I replaced the heater control valve and the short hose between the heater control valve and the heater core tube coming through the firewall and no more leaks. Glad I did not have to remove the dash and the "4th nut" directly behind the engine and replace the heater core. All is well that ends well I guess. At least I can say I was mentally ready to replace the heater core, have the process memorized now.... ha ha.

 

[EB4X]

That's what you call dodging a MAJOR bullet ...good job...

 

[Mr. Alligator]

Well… you were fortunate! Must be living right.

 

[crunchie_frog]

Well… you were fortunate! Must be living right.

Maybe my maker was satisfied with me being mentally prepared and spared me the trouble. I do not know but I am glad it was just the heater control valve. Pulling the whole dash (and putting it back in) is just not a lot of fun. No worries though, there will be another interesting job to tackle soon enough. I am down to two 5.0 AWD Mountaineers, both with 240K+ miles and both seem to need pretty regular attention. Just did the tie rods (inner and outer), upper control arms, and shocks all around on one a few weeks ago, before that it was door handles, before that leaking A/C hose...

 

[410Fortune]

I’ve got it to where I can remove a gen ii dash in about 30 min putting it back takes a bit longer

The heater control valves are all failing, they are 20+ years old and recently I have seen several fall to pieces.
This is a good time to backflush your heater core so it will last another 20 years