Pre-mature Heater cores leaks:

Use the right ant-freeze. READ THE LABEL. Use only anti-freezes that are free of silicates (sand), phosphates, borates, amines, and nitrates. These chemicals can become electrically charged and cause electrolysis. ECD or electro-chemical degradation destroys hoses as well as the metals in the system. Industry trends include using de-ionized water rather than even sterilized water. Tap water now –a- days is a big NO. You should ALWAYS test the anti freeze for a balanced PH. You want about 7.2. Anti-freeze and additives with silicates (sand) DO NOT go in aluminum cores. Anti-freeze recyclers often contain some quantities of other antifreezes like propylene glycols, ethylene glycols, and their additives. The correct answer is to thoroughly flush the system including using pure water as a rinse.

One of the biggest causes of premature leaking (like within days or months) is adding silicate based additives. DO NOT ADD WATERPUMP LUBE OR SEALANT PRODUCTS to GM applications, or any vehicles with an aluminum core.

Verify the PH. It’s not a joke. You can physically verify with a multi-meter and probes. Check the anti-freeze at idle and at 2000 RPM. Electrical current flow is an enemy to cooling systems.

We recommend Lubegard #96001 for all heater core replacements. The chemical makeup causes silicates to drop out of the liquid and settle rather than sand blast a hole in the new core. It also drastically reduces electrical conductivity of the component pieces.

Save yourself the headaches and insist on adding 96001 as a safety net. Core replacements are tough enough the first time.