Compression Check: Testing and Inspection

2007 Toyota Highlander 2WD V6-3.3L (3MZ-FE)SECTION Testing and Inspection
INSPECT COMPRESSION
(a) Warm up and stop the engine.
(b) Disconnect the injector connectors.
(c) Remove the intake air surge tank.
(d) Remove the 6 ignition coils.
(e) Remove the 6 spark plugs.





(f) Check the cylinder compression pressure.
SST 09992-00500
(1) Insert a compression gauge into the spark plug hole.
(2) Fully open the throttle.
(3) While cranking the engine, measure the compression pressure.
Compression pressure:
1.5 MPa (15.3 kgf/cm2, 218 psi)
Minimum pressure:
1.0 MPa (10.2 kgf/cm2, 145 psi)
Difference between each cylinder:
100 kPa (1.0 kgf/cm2, 15 psi)

NOTICE:
^ Always use a fully charged battery to obtain engine speed of 250 rpm or more.
^ Check other cylinder's compression pressure in the same way.
^ This measurement must be done as quickly as possible.

(4) If the cylinder compression is low, pour a small amount of engine oil into the cylinder through the spark plug hole and inspect again.

HINT:
^ If adding oil increases the compression, the piston rings and/or cylinder bore may be worn or damaged.
^ If pressure stays low, a valve may be stuck or seated improperly, or there may be leakage in the gasket.
RENDER: 1.0x

NO RELATED

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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.