1997 Lexus SC 300 AutomaticFACTORY OEM SERVICE PROCEDURE

Engine Compression

WARNING: This page is about a different car, the 1997 Lexus SC 400. However, it is still accessible from the selected car via links, so may be relevant.

To check engine compression, bring engine to normal operating temperature. Remove air intake hose from throttle body. Remove all spark plugs. Fully open throttle. Ensure engine cranking speed is at least 250 RPM when measuring compression.

COMPRESSION SPECIFICATIONS

Application Specification
Compression Ratio 10.4:1
Compression Pressure 178 psi (12.5 kg/cm2 )
Minimum Compression Pressure 142 psi (10.0 kg/cm2 )
Maximum Variation Between Cylinders 14 psi (1.0 kg/cm2 )
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.