Zreneyfex TU-32-6 6.6 L Pressure System Test Kit Replacement For GM Duramax Engine 30 InHg To 15 PSI

Instruction:1. Start the engine and turn it to normal operating temperature, turn off the engine and remove all spark plugs after the engine stops running.2. With the throttle fully open, press the connector of the pressure gauge onto the spark plug hole.3. Use the motor to drive the engine to rotate at 100-150r/min for 3-5 seconds. At this time, the pointer on the instrument will gradually rise and stop at a certain value, and the indicated value is the compression pressure of the cylinder.4. Repeat the above steps for 2-3 times to improve the measurement accuracy. Material: Made of oil resistant tempered glass mirror surface,copper interface,rubber gauge hose. Feature: Equipped with a 3-1/2 gauge reads from 30 inHg to 15 PSI. Package included: 3-1/2 Gauge Reads ,6ft Hose and quick Coupler.