There's been loads of discussion on replacing heater cores lately. I haven't searched back, but little seems to be said about what's causing most heater cores to fail. I'd mentioned the importance of changing antifreeze, especially for aluminum components & how this is often overlooked, even checked off & paid for during warranty! My presumption was that most heater core failures are corrosion from within, as has been my experience. Someone did say a tubing to core connection leaked, not why, a defect or abuse. Others must get holed from external corrosion & punctures, trauma, etc. Once read about mysterious erosion b/c of cab ground issues.

How are heater cores failing, has internal corrosion been confirmed as the most common mode of heater core failure? Does scheduled (4 years for my '98) antifreeze change effectively prevent, or contribute, to heater core corrosion? Are other brands better than the deep green FORD stuff, are there brands to avoid, or effective additives to consider?

How many are like my Dad? Paid for scheduled maintenance & probably got taken when 'by the book' items like changing antifreeze & brake fluid were reinterpreted as checking fluids & topping off, then lose patience w/stealership & end up w/F-150 built in 2/98 that never had antifreeze changed?

I'm considering changing antifreeze more often and/or use additives to try & maximize aluminum protection. Also avoid caustic cooling system flushing. Sure is the most unneccessarily difficult heater core R&R I've seen.

At least we're not hearing stories about carpet stinking of & soaked in antifreeze.

 

I haven't expeienced this problem yet and hope that I never do. On the other hand, my truck is going on 6 years old with 75k on it and I am ashamed to say that the antifreeze has never been changed. I have been wanting to change it but, you know how things keep us busy today and we never get around to doing what needs to be done.

Mine came with the Premium Gold Engine coolant that is yellow in color. It still looks the same today as the day I bought it, other than a film of road dirt on the outside of the recovery tank. I have seen many places that you should never mix the green and yellow coolants.

 

My truck went 10 years/95K miles on the origional stuff. We did a driveway "flush" right after we changed the heater core last October. Needs to be done again, as it's starting to change color again (never was completely green...always had a brown tint to it).

 

I changed mine @ 50k and will do it again @ 100K. Mine uses green and it still looked good when I changed it, but it does break down over time and lose it's anti-corrosive capabilities.

 

You bring up a good point. Loads of totally depleted antifreeze "still looked good" since the loss of "anti-corrosive capabilities" can't be seen. Its pretty much 'a no brainer' that you should change nasty looking contaminated antifreeze.

Note that the 'freeze' prevention capability apparently diminishes little, even neglecting recommended changes (4 years for my '98)-allowing those in cold climates to go 10 years. However, I've heard not only that the anticorrosive properties can be consumed, but that sometimes the fluid that's left can actually erode aluminum!

Questions remain the same. How have most heater cores failed? Is internal corrosion in fact the #1 villian? Could simple antifreeze changes prevent most heater core failures? How many cores fail from defects & abuse?

 

Good questions. Maybe some of our FTE members that have had this failure will chime in with their observations. Or post the same questions in the Cooling, Heating, Ventilation and A/C forum. Ultramagdan is the moderator for that forum and is a co-moderator of this forum. Maybe he knows which FTE member is the most knowledgeable in this area.