Hi Wully:
Based on my research, and many years of storing seasonal vehicles, it seems that winterizing the C7 requires a mixture of old and new techniques. The "new" has to do with the fuel level in the tanks. Previous thinking dictated that the fuel tanks should be full so as to prevent condensation build up over the storage period. However, according to a number qualified C7 techs, the fuel tanks should be filled to just under 1/4. This is to prevent sulphur build-up on the fuel sender which has been a problem with some cars that are not driven regularly and / or are not using Top Tier fuel. Again, based on my research, this preventative approach makes sense as the service procedure involved in replacing the fuel sender is extensive, to say the least.
So, here's how I'll be storing my C7:
- Fuel tanks filled to just under 1/4 tank. Correct amount of Sta-Bil fuel stabilizer added. Take the car for a short run just before storing so as to circulate the gas / stabilizer throughout the entire fuel system.
- Wash, dry and wax the car. Clean and wax the wheels to remove all brake dust. (It's corrosive and may cause pitting in the paint / chrome if not removed.
- 3 quarts / liters of moisture absorbent pellets (desiccant) in cloth bags placed inside of the vehicle.
- Tires inflated to 40 psi.
- Battery tender connected to the rear cargo 12V port. Yes, it's okay to close the hatch on the tender's cord.
- Indoor cover installed just to keep the dust off.
Again, this is just my procedure. There are many other schools of thought out there that, I'm sure, will work just as effectively.
Best regards
Ross