GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

DEFINITION: White smoke and/or coolant type odour above acceptable tolerances coming from the exhaust pipe may indicate coolant in the combustion chamber. Low coolant levels, an inoperative cooling fan, or a faulty thermostat may lead to an over-temperature condition which may cause engine component damage.

  1. A slower than normal cranking speed may indicate coolant entering the combustion chamber. Refer to Engine Will Not Crank - Crankshaft Will Not Rotate .
  2. Remove the spark plugs and inspect for spark plugs saturated by coolant or coolant in the cylinder bore. Refer to Spark Plug Inspection .
  3. Inspect by performing a cylinder leak-down test. During this test, above acceptable air bubbles within the coolant may indicate a faulty gasket or damaged component. Refer to Cylinder Leakage Test .
  4. Inspect by performing a cylinder compression test. 2 cylinders side-by-side on the engine block, with low compression, may indicate a failed cylinder head gasket. Refer to Engine Compression Test .

Failed cylinder head gasket.

Replace the head gasket and components, as required. Refer to Cylinder Head Cleaning and Inspection and Cylinder Head Replacement - Left Side and Cylinder Head Replacement - Right Side .

Warped cylinder head.

Machine the cylinder head to the correct flatness, if applicable and replace the cylinder head gasket. Refer to Cylinder Head Cleaning and Inspection .

Cracked cylinder head.

Replace the cylinder head and gasket. Refer to Cylinder Head Replacement - Left Side

 or 

Refer to Cylinder Head Replacement - Right Side .

Cracked cylinder liner or engine block.

Replace the components, as required. Refer to Engine Block Disassemble Engine Block Disassemble in Engine Mechanical - 6.0L

Cylinder head or engine block porosity.

Replace the components, as required. Refer to Engine Block Disassemble Engine Block Disassemble or Cylinder Head Replacement - Left Side or Cylinder Head Replacement - Right Side .