I replaced the heater core on my '93 F-150 two years ago, not long after I replaced the MAP sensor. The replacement MAP sensor went bad recently, so I had it replaced. Now, the replacement heater core is leaking. I cannot see how there could be a connection between the failure of these two parts, but I'm remembering something from the directions for installing the heater core, that I must check for electrolysis before installing the new core. I did not. If my F-150 were a boat, I would know how to check for and correct stray current. But, on a truck, I'm at a loss. Could there be an electrical issue which is killing both the MAP sensor and the heater core? Shouldn't insuring a proper ground of the core be sufficient to prevent electrolysis?
In a word ... HELP!

 

Stop buying cheap parts.

 

The only way that could happen is if the heater core is acting as part of a circuit, but that should not be, if the heater core touches metal and completes a circuit, the metal would rot the copper.

 

Agree with Sean - cheap parts will come back to bite ya - I think of them as lower-cost, but not less expensive over the long haul.

I've posted several times on my experiences with heater cores, but essentially IMO, the cheap ones don't last long and don't put out the amount/quantity of heat of a true OEM-quality core. Two years is about right based on my experiences with cheap cores.

Suggest with electrolysis, one would want to ensure electrical isolation, not grounding. This is slightly different than equipment having an intentional corrosion anode that is intended to be consumed - such as with boat motors and water heaters. Haven't heard of any electrolysis problems on these trucks.

 

Could also be galvanic action taking place. Cheap parts are made with cheap metal. You also might need to change the coolant, it stops protecting from corrosion after a while.

One note about cheap parts: I've had the same heater core in my truck since '95, 170,000 miles ago. Bought it at Advance Auto Parts. Others results may vary.