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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> Engine Mechanical >> Engine Mechanical >> Diagnostic Information and Procedures >> Coolant In Combustion Chamber

Coolant In Combustion Chamber

Cause Correction
DEFINITION: Excessive white smoke and/or coolant type odor 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 overtemperature 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.
  3. Inspect by performing a cylinder leak-down test. During this test, excessive air bubbles within the coolant may indicate a faulty gasket or damaged component.
  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 .
Faulty cylinder head gasket Replace the head gasket and components, as required. Refer to Cylinder Head Cleaning and Inspection  and Cylinder Head Replacement - Left Side  or Cylinder Head Replacement - Right Side .
Warped cylinder head Machine the cylinder head to the proper 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.
Cracked cylinder liner or engine block Replace the components, as required.
Cylinder head or engine block porosity Replace the components, as required.