2007 Cadillac STS Owner's Manual - Page 392

Checking Intercooler System Coolant (4.4L V8 STS-V Engine Only) Notice: This vehicle has a specific coolant fill procedure. Failure to follow this procedure could cause your engine to overheat and be severely damaged. Park the vehicle on a level surface and turn off the engine. When the engine is cold, the coolant level should be visible in the intercooler fill neck. Adding Coolant If you need more coolant, add the proper DEX-COOL® coolant mixture at the intercooler fill neck, but only when the engine is cool. See Cooling System on page 396 for instructions on how to add coolant to the intercooler fill neck. See Engine Compartment Overview on page 373 for the location of the intercooler system pressure cap. 392