The owners manual says to replace the coolant at I believe 5 years or 150,000 miles. Of course just like oil changes this is a one size fits all recomendation. Different operating conditions may require different change intervals to achieve the best protection for the engine.
Dex Cool made by Havoline for GM, adds organic acids to ethylene glycol as additives instead of using silicates & phosphates that are added to conventional green or blue antifreeze. The organic acids last much longer and almost eliminate hard water deposits from forming & there is much less abrasion to the waterpump seals.
DO NOT: Use tap water. Use Distilled water only. It has been reported that Dex Cool reacts with chlorinated tap water, creating corrosion problems & sludge plugging up the cooling system.
DO NOT: Mix Dex Cool & regular anti freeze. If in an emergency the two are mixed get the system flushed as soon as possible and refill with the correct coolant.
DO NOT: Start using Dex Cool in a vehicle that did not come with Dex Cool from the factory. The silicate deposits are already in place & will keep the organic acids from working.
With the longer change interval DO NOT forget about changing your coolant. There is a large gremlin lurking out there. It is electrolytic metal corrosion (EME). EME is the damage done to engine parts by coolant (orange or green) reacting with the high amount of aluminum in newer vehicles. The cooling system becomes a storage battery resulting in pitting and cratering of blocks heads timing covers radiators etc. This may be mistaken for bad castings or other causes but it is EME.
There is a simple test for EME. Take a multi meter & put it on the lowest DC voltage range. Stick the positive probe in the coolant at the radiator cap. On your corvette stick the positive probe in the coolant in the reservoir. Hint you may need to use a piece of bare wire or other metal extenton to reach the coolant. Then touch the negative probe to the engine. If EME is present the meter will read between 0.5 and 1.75 volts. If the reading is in this range change the coolant. This is not stray current from the electrical system. It will work even with no battery in the car.
This test is so easy to do I will be doing it occasionaly & if it starts getting near 0.5 volts I will be off to the store for some Dex Cool & distilled water! Even if you keep passing this test do not ignore the time or mileage change criteria. The organic acids deplete over time and need to be replaced. To be safe I won't be waiting 5 years to change mine. I checked my 2002 Z06 last nite. The car has 500 miles on it. I got a reading of 0.10 volts.
If anyone else wants to use additives (water wetter etc. help yourself. But remember you are altering the chemical makeup of the coolant and the results are unknown to the user. Make mine a Dex Cool & Distilled Water only thanks.
If any one has waided through all of this I would like some tips. How can you drain/flush the cooling system at home. I have not been able to locate the block drains on my 2002 Z06. I do not want some one else working on my car so I want to be able to do it myself. HELP PLEASE
