If it is coolant that is leaking, it is due to a corroded heater core. Leaking radiators and heater cores are common on GM vehicles that use the red Dex-Cool antifreeze. GM advertised that as "lifetime" antifreeze to make their cost of regular maintenance appear to be lower than that of their competitors, but they put stickers under the hood that say to replace it every three years. Even the Dex-Cool company does not recommend that. The water pump lubricant, corrosion inhibitors, and other additives wear out in about two years, then the coolant becomes acidic and attacks metal parts.
You can verify if acid build-up has led to this problem with a digital voltmeter. If you have a radiator cap, remove that to do this test. GM left the caps off most of their vehicles so you will have to go to the reservoir. Set the voltmeter on the twenty volt range. Place the negative probe on the battery's negative post or on a paint-free point on the engine or body. Place the positive probe into the coolant, then take the voltage reading. If you are able to put the probe in the radiator, it cannot touch anything metal, just the liquid. Anything over 2.0 volts is significant. At a minimum, the coolant should be drained and refilled. The better solution is a complete system flush. To reduce the number of problems this antifreeze causes, many mechanics will not use Dex-Cool antifreeze. There are a lot of different brands and formulations on the market. The people at the auto parts stores should be able to find one with the right additives to meet your engine's requirements. Do not just pick the cheapest one off the shelf as it may not provide the right protection for the different metals in your cooling system.
Monday, December 11th, 2017 AT 1:48 PM
