Hello all, I have a question about something a NAPA guy told me about a service bulletin he learned about that the heater cores in the F series trucks 1999-2003 needed to be grounded out because of a corrosive electrolysis problem occuring in the coolant system. Have you all heard of this or is this BS?

 

I'm not sure about your particular vehicle but this is a real concern. Some Ford taurus for instance does have a heater core problem and grounding the heater core is suggested in TSB's. You could search this site for TSB's on your truck to see if it pertains. I don't recall seeing anything on our diesels. Some one will chime in if they heard about it.

If necessary The fix is pretty easy, I used a hose clamp and wire on one of the heater core pipes protruding from the firewall and grounded it to chassis. It's already grounded to the engine through the coolant.

 

Please don't think I'm questioning your wisdom here Cuda, I just want to understand in case a similar issue arises.
Is the coolant a suitable conductor to be a reliable ground path? I would think that you would want to avoid using or allowing the coolant to be a ground path.

 

I think this is why the PSD reqiuer a additive to the coolant or speacal coolants to prevent this from happening. I was planning on changing my coolant because of no history of it and its the green stuff. I was planning on using the rotella ELC. Im assumming this coolant is what most of you guys are using.

 

The coolant IS a ground path between the heater core and the engine, wanted or not. They are not mechanically connected and that is likely where the trouble begins. Most heater cores are aluminum and becoms the sacrificial anode. By providing a mechanical ground circuit the heater core is bypassed electronically. At least that's been my thoughts as to why some heater cores have ground wires.

If you want to check your cooling system for electrical leaks:

Use a digital volt meter and connect the - lead to battery ground the + lead in the coolant in the radiator without touching metal, there should be no voltage over ~0.01V, if so change the coolant and check it again.

Next, Run the motor @ ~1500 rpm (high charging rate) with all accessories off, if the voltage is above ~0.03v then your charging system is leaking electricity.

To fix it, turn all accessories on while running @ ~1500 rpm, watch the voltmeter, turn off each accessory one at a time, when the voltage drops below 0.01v you have found the circuit with a poor ground. It may be a combination of a couple curcuits.

Do the same test while cranking the starter, a poorly grounded starter can destroy the radiator and or heater core in a matter of weeks.

 

I'm not sure if the SCA additive for diesels are used to combat elecrolysis. Here's an article on SCA levels:
http://www.freeautoadvice.com/diesel/cav.html

 

Thanks for the explanation Cuda, that is good info.