Air Induction Systems: Turbocharger

NOTE: Faulty turbocharger is replaced as a unit. Wastegate is press-fit and not available separately.

WARNING: Turbocharger and related components operate at very high temperature. Always allow system to cool or use proper protective clothing to prevent severe burns.

CAUTION: Before disconnecting or reconnecting turbocharger, thoroughly clean all joints, pipe unions and connections. Prevent dust and dirt contamination. Cover all components with dust-free paper or seal in plastic bags. DO NOT use cloth or rags. Avoid nearby use of compressed air. DO NOT move vehicle or work in dusty conditions while turbocharger is open or removed.

Wastegate and blow-off valve are both normally closed, opening only when boost pressure becomes too high. Not opening will allow turbocharger to create too much boost pressure, which can cause immediate and serious engine damage. Opening too soon will limit boost pressure and reduce engine power.

Before testing wastegate and blow-off valve regulating functions, inspect system for leaks and ensure control line to wastegate is not plugged, loose or leaking. To achieve valid test results, other engine performance factors, such as injection timing and valve clearance, should be within specification or adjusted correctly. Engine should be warmed to normal operating temperature for pressure tests.

Boost pressure specifications are "overpressure" values, given in relation to normal atmospheric pressure. For example, zero pressure on gauge is actually atmospheric pressure or 14.5 psi (1.02 kg/cm² ) absolute pressure. A boost pressure specification of 10.2 psi (.72 kg/cm² ) as given in this test would be read as 10.2 psi (.72 kg/cm² ) on an overpressure gauge, or 24.7 psi (1.74 kg/cm² ) on an absolute pressure gauge. Ensure identification of gauge type and if necessary, convert specifications and readings to the same scale using PRESSURE CONVERSION GRAPH. See Figure .