2010 Cadillac CTS Owner's Manual - Page 322

9-22 Vehicle Care Adding Coolant to the Intercooler System Coolant (CTS-V) 2. Then keep turning the pressure cap slowly and remove it. 3. Add the proper DEX-COOL® coolant mixture to the fill neck until the coolant is within the cold fill region. With the intercooler system pressure cap off, start the engine and let it run for a couple of minutes. Then turn the engine off. By this time, the coolant level inside the fill neck may be lower. If the level drops where coolant is no longer within the cold fill region of the fill neck with the engine off, add more of the DEX-COOL® coolant mixture to the fill neck until the level is again visible in the cold fill region. 4. Then replace the pressure cap. Be sure the pressure cap is hand-tight and fully seated. Checking Coolant in the Intercooler System (CTS-V) The vehicle must be on a level surface when checking the coolant level. The super charged engine intercooler coolant fill neck is located in the engine compartment on the passenger side of the vehicle. See Engine Compartment Overview on page 9‑6. On the coolant fill neck, there is a cold fill region between the two horizontal lines shown. Check to see if coolant is visible in the coolant fill neck. If the coolant is not visible or below the cold fill region in the fill neck, add a 50/50 mixture of clean, drinkable water and DEX-COOL® coolant at the coolant fill bottle, but be sure the cooling system is cool before this is done. 1. Remove the intercooler system pressure cap when the intercooler system hoses are no longer hot. Turn the pressure cap slowly counterclockwise about one-quarter of a turn. If you hear a hiss, wait for that to stop. This allows any pressure still left to be vented.