I had to replace the heater core on my 2008 5.4 crew cab last january. replaced with a core from ford, and it needs replaced again, after only 9 months. Any idea what would cause this ?

 

Captdave,

Suspect mine is in need of replacement also.
It's an '08 as well...windshield starts to fog up when the truck gets warm.
Don't really notice the tell tale smell of antifreeze however.
What led you to know for sure it was the core? Pressure test??
Did the folks at Ford replace it? And did you have to have the entire dash removed?
I've replaced a few heater cores but can't imagine the effort needed to get this one out!

Perhaps a flush and fill is needed to prevent internal corrosion.

 

Captdave,

Suspect mine is in need of replacement also.
It's an '08 as well...windshield starts to fog up when the truck gets warm.
Don't really notice the tell tale smell of antifreeze however.
What led you to know for sure it was the core? Pressure test??
Did the folks at Ford replace it? And did you have to have the entire dash removed?
I've replaced a few heater cores but can't imagine the effort needed to get this one out!

Perhaps a flush and fill is needed to prevent internal corrosion.

 

I would smell a slight odor every now and then. After a couple weeks I found the pad under the carpet wet. Yes the whole dash was removed. I had it done at a local garage that does all my work, he did call a friend of his at ford who said in 30 yrs. as a mechanic at the ford garage, he never changed a heater core in a F150. Ford did warrent the first heater that was replaced.

 

From what I have learned early failure of a heater core is probably due to improper cushioning of the core in the box causing expansion and contracting to crack the core

 

Did you have to remove the steering wheel when you pulled the dash out to gain access to the heater core?

 

Not sure, had a local shop do it.

 

Have you changed the coolant at the suggested intervals? Seems like that would be a factor but maybe I'm wrong. Mine is the original at 204K at this point.

 

It was either physically damaged causing the premature leak, or electrolysis has taken its toll.
Ever wonder what the electrical ground strap to the heater core was for?
Electrolysis.
2 dissimilar metals will corrode as they set up a natural current due to the common element of being in contact with coolant.
Being as new as the heater core is, it could be either one....damage or corrosion


Look for ford TSB : 06-21-19 dated 10/30/2006
I know the year is a little older, but I believe it still applies
The TSB gives a procedure for testing to see if Electrolysis is the culprit
The TSB also (for some reason) says NOT to put a ground on the heater core, even though it has been relevant in the past on fords.

 

My heater core has finally gone! The issue disappeared when I last posted back in 2013...
Now the windshield gets really foggy and the anti-freeze smell is there.
I've searched high and low on this site for instructions on how to replace the heater core, but no luck so far. Any help would be greatly appreciated.

Many thanks!

 

I'm in the same boat as Gordo. I'm new to this group and don't expect anyone to jump thru hoops for me. I sure could use a "point" in the right direction if anyone knows of a right up for the heater core removal/replacement.

 

I've managed to confirm what others here have said....the dash does in fact need to come out!
With time, effort, and a lack of patience working against me at the moment, I've decided to take it to the local shop.
I spoke to the mechanic, and he said he's done about 6 or 7 of them now....not a hard job, but very time consuming (plus he has all the right tools!). $150 (plus labor) for the core, plus he recommends two switches be replaced at the same time, as these are known to fail as well.
He said, again as mentioned here, that the foam supporting the core wears, and then the tubing rubs on the frame!!!!! GRRRRRRR!!!!

Oh, I did happen to test the coolant for conductivity...it was only 0.01V, so no problem there.

Now for the best part!!! Well sort of I guess lol....
After a lengthy search I was able to find a detailed step-by-step guide to removal and installation (it's for a 2009 however), but I hope it helps someone out there!!!

Cheers

https://docs.google.com/document/d/1...it?usp=sharing

 

Hmmmm the doc says 2002!!!