Weather is cooling down so the other day I turned on the heat after many Summer months of not using it. All of a sudden my windshield began to fog up! My first thought was "heater core" so I did more investigating. The carpet under the passenger side was dry however once I peeled it back I noticed the padding underneath was "slightly" damp but looked like it had been wet and dried possibly many times over. My coolant level seems normal by visually checking the overflow reservoir. That level fluctuates at different times.

MY QUESTIONS:
Is this likely a heater core?
Where can I find a "how-to" on a 2004-2006 heater core replacement? All I find is earlier models or Super Duty.
Should I replace other parts while Im in there doing a heater core? Blend door, etc?

Thanks in advance for all your input.

 

check to made sure the ac water is draining out. not sure where to drain is?

 

what would be the best way to do that? Just idle in the driveway for 15min with A/C on max?

 

You could do that and then turn everything off and wait for it to drip. It will drip as it the core gets warm again.

I think if you pull back the carpet (pass side) up by the heater box, the vent goes thur the firewall there, somewhere around the back side of the cylinder head on the right side. Could use air and a small hose to blow it out.

 

If it is the heater core, you should smell the antifreeze when you first get heat!

 

More to add...I bought the truck new in 2006. At about only 800mi on the truck (raining at the time) it broke down. Just died and wouldn't start. Zero response from the turn of the ignition key. No click, no buzz from fuel pump, NOTHING! Towed it to the dealer and they said it was a known problem with a leak at the windshield. They had to replace (bear with me) an electrical part? under the hood that had gotten wet and been shorted out and they replaced the battery also. Ive driven it nearly 10yrs and 145k mi without a similar issue.

Ive replaced the windshield twice over the years. From what im reading about leaks in other threads could it be plausible that the glass replacement somehow created this same leak?

I wish I would've gotten more information about that leak/repair the dealer did 10yrs ago.

I don't smell antifreeze at all in the cab.

 

I think its the ac drain.

 

upon further investigation ive come to conclusion that the moisture in my carpet pad is NOT antifreeze. Thursday I will pull the tire and plastic shroud and get a visual of the AC drain. It should be apparent if the cheap foam/rubber collar in the firewall has deteriorated at all.

 

The AC Drain Tube with part number F3LY-6A614-A has apparently changed to 4M2Z-6A614-AA.