Heater core

[backroad101]

Quick question. Is the only way a heater core would go bad is if it starts leaking?

 

[chrwilkins30]

I would think it would have to be leaking or clogged beyond claening to need replacement.

 

[shane96ranger]

No, your heater core wouldn't cause it to overheat. It will be something else in the system, possibly a blockage or maybe the system that has not been properly burped. However, those symptoms would show up in the summer as well.

Not to sound like you are a doofus, but you are using a 50/50 mix antifreeze, right?

 

[adsm08]

The heater core is only for heating the cabin. You can bypass it completely and have no detrimental effects of the performance of the cooling system.

Now what really confuses me is that your issues occur in the winter. Most cooling system issues hit their peak in the warm summer months.

 

[shane96ranger]

Now what really confuses me is that your issues occur in the winter.

That's why I was wondering if he was running straight, or too much water.

 

[RonD]

I had to do my '94 4.0 heads 3 times, 9 months apart.
1st one was real, water pump failed and I tried to nurse it home, cracked head
Redid the heads
9 months later, over heating, head gasket, one of the heads bolts was just over finger tight when disassembled?? OK I screwed up
Redid the heads
9 months later, over heating head gasket???!!! WTF

I have been doing head gaskets for 35 years on all kinds of engines, WTF!
My 20+ year old Mr. reliable craftsman torque wrench had packed it in.
I was under tightening the stretch bolts, not by much but enough.

New torque wrench, redid the heads, I guess we will see, not at 9 months yet, lol

My heater core was not getting hot enough, warm but not hot, I did a back flush and it is working well now.

And I agree, heater core would not cause over heating unless floor in cab was a lake, a warm stinky lake

Over heating is cause by a blown head gasket, bad water pump or rad or T-stat, or rad cap or fan, can start the over heating, but unless you run the engine over heated for an extended period, the head gasket should be fine.
These are cast heads not aluminum, aluminum heads will blow a gasket right quick when over heated.

Maybe there is a block defect that is taking awhile to show up and head gasket is blowing and then you see the over heating, so the other way around