I am a newbee.I ride a '03 GMC Sierra 1500 HD 4WD Crewcab with a 6.0 AT purchased new. She just turned 48000. Just got the ride back from the dealer shop. THIRD heater core in two months. After the second went bad, dealer called GM engineering. They told the dealerthe truckhas excessive electrolysis. They replaced the core, added a few ground straps to the core necks, drained and refilled coolant and added a box of baking soda.

OK. I jumped on the internet and learned all about electrolysis. Everything I read sez that a reading above .4 VDC is bad. Dealer sez mine went in at 6.8 and is now 4.8 VDC. I confirmed this myself with my own DVM.

Dealer sez newer vehicles have higher static readings.

Anyone out there have any experience with this??

Any help will be appreciated...