Hello friends,
In Jan., replaced heater core, 2 months later, new core leaks. Purchased another core in April, and instructions inside the box, not in the previous purchase, state that additions of aftermarket electrical devices,(ie: radios, electrical guages and such) can cause the core to leak unless these devices are propely grounded.
Question: Has anyone ever read this instuction?
Does the core need grounding, or the electrical device that was added?
And why does this happen in the first place?
Thanks for all help

 

Where was the heater core leaking from?

 

1975ford,
The core leaks at the sil-brase at the top of the core, however, the previous one leaked at the lower part of the core.

 

I have no clue why a radio ground would cause a heater core to leak. The heater core should be grounded by the bolts that hold it to the fire wall......

I changed the heater core in my truck about a year ago......I don't think I got any instructions.......

 

Make sure the rubber padding is not worn or worn in places on heater core which helps the heater core from scrapping or binding on the box. Inspect the location on box where the heater core could of rubbed.

never heard of a radio ground, and have never installed a ground as mentioned. Never encounter a heater core leak when R&R.

 

See Ford TSB 01-16-06 for a discussion on this issue: TSB 01-16-06

It covers most Fords manufactured for the last 20 years.

Steve

 

This is caused by stray currents that find their way to ground through the heater core, causing electrolytic (galvanic,) corrosion. This is not that rare a problem. The instructions are right on as far as poor grounding being the cause. If you have any aftermarket electrical componants, double check the grounds. It can also be that your entire dash is poorly grounded, or the even the firewall.
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If the truck has any electrical alterations, look there first for poor grounds. If there is no elec monkey business at all, I would simply double check existing grounds. If you can't find them, don't worry. Just make some new ones and add to the truck between the firewall and engine, dash (near the heater core,) and insure that your engine has a sound grounding connection the the chassis. Disassemble, clean, grease and reassemble all these grounding connections and you will probably have this solved.

When you are done, run the engine at idle and put a volt meter (on it's lowest scale,) between the battery negative cable connection and put the pos lead in the coolant, not touching metal. What does it read? If it is over .02 volts, flush the system and refill. Check it again after a couple of use. If the voltage reading is still up there, you still have an open ground somewhere. This is important because your radiator is also at risk.

I didn't read the TSB that project posted, but if it is the one that says to add a ground to your heater core, that is wrong. It's a band-aid fix.

OK. All the above is 95% likely to be the problem. The other, 5% possibility is static charge. This can take place if you have a plastic squirrel cage blower in the heater. I do not know if Ford trucks are subject to this or not. But you will notice on some cars, notably Cadillac, there is a foil lining inside the blower housing that is there to ground out the static charge.

 

bdox,
Yes, I read the tsp about last ditch effort to ground the core. I'll do as you suggest and check all my existing grounds. Not aware of any electrical sys. changes that I may have made. Can grounding the core to the chassis or frame cause me a problem (band-aid fix), or are you just saying that this grounding fix does not address the problem at hand. Thanks for your insight.

 

I believe that Ford put out that tsb in desparation because of numerous heater core failures and paying technicians for hours and hours of non-productive troubleshooting time. I don't know how it works, but the thinking is completely backwards in that it encourages current flow rather than curing the problem. It must have the effect of relieving the charge on the core so that it would prolong the life of the core past the warranty period.

Extra, precautionary grounds won't ever be detrimental.

As to whether the Ford band-aid fix will hurt, I don't think so. But on the other hand, if you install a ground to the firewall (for instance,) and the firewall ground it the problem, you accomplish nothing. (But then your coolant becomes the normal path to ground for the problem circuit and may cause further galvanic problems elsewhere in the system.)

This is not a very gratifying repair. It isn't one of those things where you say, "Ha, fixed that sucker!" But that voltage test in my earlier post will help you feel that you have found the cure. By the way, If you haven't taken anything apart yet or drained the system you could make the test before you start just for comparison. If you have a helper to hold the probes and read the meter, you could do it with the engine on and off, operating all the electrial systems one at a time to see if you can isolate the problem circuit or circuits. You may not find it that way but if you do notice a rise in the voltage reading in the coolant it's likely you know which circuit has the faulty ground. Then you would get that satisfied feeling, knowing you have got it pegged.

 

bdox,
I'm convinced! This weekend, I'm going hunting for the elusive ground. Actually, I believe I do have a starting place for my search. Thanks again to you and FTE guys and gals

 

Cabrock... Any result on your search?

 

Hello Bdox and all,
Sorry for not getting back to the forum for so long, have been doing some field work without my computer.
First, let say that the heater core problem is fixed. My first initial test indicated .03 volts at the radiator neck fluid. So I began by identifying all the grounds that I could, so as to track the ones I messed with. Sure enough, a firewall ground strap was so gunked with grease and dirt that I could not see that the retaining nut had worked loose, and the strap was not tight. Removed it and attached a new terminal loop, and a locking nut, checked a few others for good measure, and all is well. I now have 0.0 volts at the rad. Put in a new core. Now, time will tell, but I feel good about this fix.
Thanks Bdox

 

Where was the ground strap located?
I will be tighten and inspecting those ground wires, ever so often.

 

Very cool. So much nicer when you can actually put your finger on the problem! Nice work.

 

1975FORD,
The strap is located drivers side, from engine block side at /above oil pan, a boss in the block it is attached to, and it runs up to the fire wall at what I think is the wiper motor, and grounded there. The connection at the block was the damaged connector.