SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSMAZDA20086 S SPORT, 4D HATCHBACK, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 631 (ENGINE MECHANICAL (SERVICE INFORMATION))COMPRESSION INSPECTION
2008 Mazda 6 s Sport, 4D Hatchback, Standard

Compression Inspection

2008 Mazda 6 s Sport, 4D Hatchback, StandardSECTION Compression Inspection
WARNING: This page is about a different car, the 2008 Mazda RX-8. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:
  • Hot engines can cause severe burns. Be careful not to burn yourself during removal/installation of each component. 
  • Fuel vapor is hazardous. It can very easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. 
  1. Remove the engine cover. (See ENGINE COVER REMOVAL/INSTALLATION ).
  2. Verify that the battery is fully charged. (See BATTERY INSPECTION )
  3. Warm up the engine.
  4. To decrease the exhaust system temperature, stop the engine and leave it as it is for approx. 10 min.
  5. Remove the trailing or leading side spark plug of the front and rear rotors. (See SPARK PLUG REMOVAL/INSTALLATION )
  6. Disconnect the eccentric shaft position sensor connector. (See ECCENTRIC SHAFT POSITION SENSOR REMOVAL/INSTALLATION. )
    CAUTION:
    • To cut the fuel injection and ignition, make sure the eccentric shaft position sensor connector is disconnected. 
  7. Measure the compression pressure using one of the following procedures:
    1. Install the SST (49 F018 901)  to the trailing or leading side plug hole of the rotor housing.
    2. Set the SST (49 F018 9A0B)  as shown in the figure.
      Fig 1: Measuring Compression Pressure
      G04562722Courtesy of MAZDA MOTORS CORP.
    3. Depress the accelerator pedal fully and crank for 5-10 s  .
    4. Read the compression and engine speed.

      Compression pressure 

      • Standard: 830 kPa {8.5 kgf.cm 2  , 120 psi) [250 rpm] 
      • Minimum: 680 kPa {6.9 kgf.cm 2  , 98.6 psi} [250 rpm] 
      • Standard difference in chambers: Within 150 kPa {1.5 kgf.cm 2  , 21.8psi} 
      • Standard difference in rotors: Within 100 kPa {1.0 kgf.cm 2  , 14.5 psi} 
    5. Perform the same procedure for the other rotor housing.
    6. If the compression is at the minimum or less, or the difference in the chambers and difference in the rotors exceed the specifications, replace or overhaul.
      CAUTION:
      • If the engine speed when measuring compression differs from the standard, adjust according to the graph. 
      1. A : Standard compression pressure
      2. B : Minimum compression pressure
      7. Fig 2: Compression Pressure Graph
      G04562724Courtesy of MAZDA MOTORS CORP.
  8. Install the spark plugs. (See SPARK PLUG REMOVAL/INSTALLATION )
  9. Connect the eccentric shaft position sensor connector. (See ECCENTRIC SHAFT POSITION SENSOR REMOVAL/INSTALLATION )
  10. Install the engine cover. (See ENGINE COVER REMOVAL/INSTALLATION ).
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

When to See a Mechanic

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

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