K Yukon/Denali 4WD V8-5.7L VIN R (2000)
Steps 11-26
The most likely causes of insufficient heating outside the heater system include a low coolant level, a faulty thermostat, a partially or fully clogged
heater core or hose, an obstruction to the air circulation, or an air leak past a faulty seal into the passenger compartment. For the proper temperature
verification, use the Tech II
