Well, just to let you guys know incase any one else is having the same problem: I have a 1998, 4.6 V8 (89,200 miles), Extended Cab, Flairside, 2 Wheel Drive F150. I love this truck, have taken incredible care of it, and am the original owner. For the past year I have had an ongoing problem with the heater core. The local dealership has replaced it 7 times, flushed the coolant fluid numerous times per change, changed and checked tubes, hoses, clamps, and replaced the thermostat twice due to an excessive amount of rust and debris built up inside the engine. The heater core was constantly melting supposedly due to an electrical charge passing through it. After going through several solutions, fixes, and talks with Ford engineers (gotta love the internet), the dealership told me the ultimate diagnoses and solution = the engine block was pitted and I needed a new engine. That sucks. I do not know how something like this happens but to any of you who are having the constant heater core problem, be prepared for the worse. The dealership has been great to me and I am now on a first name basis with my service advisor. I have talked to Ford and after telling them my case, they are not helping me in anyway with the new engine. This is coming straight out of my pocket. Yes, I know that business is business but apparently 30 years of customer loyalty means nothing to Ford. Hopefully none of you will have this problem.

 

I totally fail to see how a pitted block would cause the heater core to fail or melt or even why a pitted block would need replacing unless it was porous.
Every engine block I have ever looked down is pitted to some extent.
Assuming the anifreeze was at the correct level, I can't see where the problem is.

Sounds like B.S. to me.

 

I'm not undrstanding what you are saying beyond core failure.
What is the failure, specifics?
Overheating, corrosion, blockage, rupture?
Radiator cap the right one?
Thermostat in in the right direction?
Head gasket leaking combustion into the cooling system, raising pressure too high and adding extra heat.
More than one problem at the same time?
If you have a lot of rust, it is (to me ) a sign that the coolant was nearly all water and or very old and acidic, allowing the block to rust up. Did you often run just water in the summer?
Some times there is a restriction put in the feed hose to limit pressure drop accross the core. The restriction is a little greater than the heater core so the pressure drop acrossed the core is less.
I sure would not change an engine for a heater problem.
I have, however had various heating problems over the years with different trucks that required reverse flushing the core, changing a radiators for blockage in the lower 1/3 of the radiator core that causes funny things to happen.
Better to figure out the problem than to spend big money only to find out you still have the same condition.
Good luck.

 

I'd slap another new heater core in it and trade it in. Your 30 year dealership can help you with top dollar on the trade (they will auction the truck) or they can go pound sand. It's seven years old, you're due for a new one.

 

I do not think he is nessecarily due for a new truck, especially with pretty low mileage for it's age. If you get the engine replaced and it does not fix it.. that will be what, atleast 3500 dollars wasted. Have you taken it elsewhere to get another heatercore put in? Maybe they are doing something wrong.

 

after revewing the above post ...a new engine is the solution to no heat?..well i agree with adam and bluegrass...you have to search elsewhere...maybe a bad heater hose?...jeesh i had some cars/trucks in the past where the radiator was full of junk...nothing a good cleaning would'nt take care of...and plenty of heat in the winter...."melting" heater cores?...lol thats a new one...zap!

 

WHOA!!
Holy Freakin crap!
Back the engine swap bus up!
Unless there is a major part of the story that I dont know about... Then that is like replacing the entire axle because you keep getting a flat tire.

If the engine is indeed severly pitted. If you can see it, then you can polish it!
Since it's out of pocket AND out of warranty.. Take it to another mechanic and have them look at it. Worse case scenario they tear it down, send it to a machine shop where they shave it, weld it, plug it, slug it, punch it. or what ever needs to be done. That would probably be alot cheaper than a new engine and will run better too. BUT I don't see that causing you to go through Heater cores. Becareful next they might be wanting to replace your flex capicator.

 

try putting a ground wire on the heater core.it might be electrolysis

 

3 dealerships have looked at this truck and two have replaced heater cores. The first three times the heater core was replaced based on the assumption of "bad part" or "bad install job". The next four times after researching together with Ford engineers, they figured it to be the electrolytes in the new, all-synthetic coolant fluid used by Ford. This was causing an electric charge to be built up somewhere in the engine and then shot to the heater core, which melted the part. I saw it, the part looked like someone took a torch to it. The metal was discolored yellow, purple, and blue. They ran grounding straps so the charge would go elsewhere but it did not work. Even with the Heat/AC off, the coolant fluid was burning, causing smoke inside the cabin, a bad smell, some coolant actually made it into the cabin through the bottom at the center of the dash, and shorting out part of my electrical system (the blinkers were the first to go). When you turned on the Windshield Defroster, smoke would flood in from the vents and it looked like a Cheech and Chong truck. I do not touch this truck, only Ford certified mechanics do. I've put on an AirForce One intake and Superchips mod (the blue one that plugs in the computer) myself, and had a Magnaflow SIDO exhaust installed elsewhere. I've had the chip for 4 years, Intake for a month, and exhaust for 5 years (started with a Flowmaster then moved to Magnaflow two months ago).

 

As stated above it leads me to believe it is a electrical cond. Is the block grounded to the frame or the firewall ?

Ever had the alt go out ? or for that matter any other strange electrical problems in the past ?

Hit by Lightning perhaps ? I know for a fact lightning has strange effects on stuff

 

This sounds like an electrical or ground problem. Not an engine problem. Have you changed brand or types of coolant? I would try adding good ground straps to the heads, block and connect to the frame, on both sides. one at the front and one at the back. Also as already stated put a ground on the heater core. I really dont think a new engine will fix this problem unless by its by luck.

 

Your dealer is BSing you something bad. Right now your dealer is partying their asses off knowing that they are making some money on you. This is what they are doing........

 

I just got back from the dealership and had a look at the old engine. The heads were still on but the intake was off. Where the intake sat there was nothing but rust, debris, and a bunch of junk. I ran my finger over it and got 1/2 an inch of black crud. It looked like the whole area was rusted. Any reason for this on an engine with only 89,000 miles and regular maintenance?

 

That almost sounds like somebody mixed red and green antifreeze in it. It makes a nasty gritty red clayish/rusty looking thick muddy mess.

 

Have you checked to make sure all the ground straps on the truck are in good shape and making good contact with the body? Sometimes there can be rust under the contact points causing a charge to build up on a particular area of the truck. I personally wouldn't trade it off on somebody else. If not a grounding problem, I have no idea where the current is coming from unless there is an open wire/conductor somewhere. If you can't fix it, that truck needs to disappear!