Originally Posted by oldxr
Semi-retired autotech-I have changed out a pile of heater cores.The GM cooling system tabs work great-last time I used some it was on a H1 Hummer with a leaky head gasket.Caddy dealers always have them.The reason heater cores fail is from not changing the coolant-it turns acidic after awhile and the heater cores are aluminum on late model cars & pu's.Pulling the dash isnt that hard-just time consuming and you need to be parked in the middle of a garage because both doors will have to be open.Follow a service manual.A good set of torx bits and a 1/4 drive socket set with extensions will be needed.Sometimes I pull the seats-you make up the time spent on this in the end.
working under the dash is top of list of worst jobs to do.
this is why I'll always install Bars Leak long before any problems becomes due. even if my cooling system is not leaking. Bars Leak also conditions coolant and lubricates your waterpump.
ethylene glycol the main ingredient in anti-freeze really doesn't wear out. but anti corrosion additives do get depleted. installing Bars Leak helps maintain coolant.
only use the original pelletized version of Bars Leak. adding something wrong to your cooling system could really screw it up major.
not a proponent of changing out anti-freeze just to renew anti-corrosion additives. have ran the same anti-freeze for 20+ years on multiple vehicles with zero problems. but they all had Bars Leak installed right from the beginning. then anytime radiator hoses were renewed. Bars Leak reinstalled.
How to Check for Electrolysis Corrosion
With the engine running and at normal operating temperature, use a digital voltmeter to check for voltage between the coolant and the battery negative (-) cable. Carefully remove the radiator cap or coolant reservoir cap (use a rag and open slowly as the system will be under pressure and hot steam may blow out of the opening). Insert the positive (+) voltmeter lead in the coolant, and touch the negative (-) voltmeter lead to the battery negative post. If you see a zero reading, that's good because it means there is no stray electrical current flowing through the coolant. But if you see a reading of 0.300 volts (300 millivolts) or higher, you've got electrolysis and potential trouble.
Snap-on cooling system pressure tester to make sure everything is holding tight