air loss. Aloud hissing of air at the carburetor indicates a leaking intake valve, or valves. Excessive hissing of air at the oil filler tube (crankcase) indicates an excessive air leak past the piston rings. Bubbles observed in the coolant at the radiator indicates a leaking head gasket

As in vacuum testing, indications are not conclusive. For instance, a leaking head gasket may prove to be a cracked head, or bad rings may be a scored cylinder wall. The important thing is that the source of the trouble has been pinpointed to a specific area, and a fairly broad, accurate estimate of repairs or adjustments required can be made without dismantling the engine.

Q17. Overhead valves are adjusted with the engine in what condition?

Q18. When you perform a wet compression test and the reading goes up, what is the most likely problem?

Q19. You make a vacuum gauge test at sea level with the engine idling at 550 rpm, and you get a reading of 10 inches. What is the most probable cause?

Q20. When performing a cylinder leakage test, you notice a loud hissing of air from the carburetor. This is an indication of what type of problem?