Practice question

A coolant odor and white residue are found around a school bus diesel's exhaust outlet, and the surge tank shows combustion bubbles during cranking. The MOST likely cause is:

  1. A head gasket, cracked head, or cracked cylinder liner allowing combustion-to-coolant communication
  2. Normal SCR water vapor
  3. A loose exhaust clamp
  4. A dirty air filter

Answer: A — A head gasket, cracked head, or cracked cylinder liner allowing combustion-to-coolant communication

The correct answer is shown above. Try the full quiz for additional practice.

Practice more: ASE S2 Diesel Engines (School Bus) Practice Questions - ASE S2 - Diesel Engines (School Bus) Certification Exam →