Drive Engine Run-Up (DERU) Load Test
WARNING: This page is about a different car, the 2004 Mercury Mountaineer and 2004 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
To carry out this test, proceed as follows:
WARNING:
Block the front and rear wheels, and apply the parking brake and the service brake, or injury to personnel can result.
CAUTION:
Do not carry out the Engine Load Test for more than five seconds or damage to the transmission or transaxle can result.
Block the front and rear wheels.
- Apply the parking brake and the service brake.
- Install a tachometer.
- Shift the transmission into DRIVE, and increase and decrease the engine rpm between an idle to approximately 2000 rpm. Note the engine rpm and, if possible, determine the vibration frequency.
- Repeat the test in REVERSE.
- If the vibration/noise is duplicated when carrying out this test, inspect the engine and transmission or transaxle mounts.
- If the concern is definitely engine speed-related, carry out the Engine Accessory Test to narrow down the source.
- Proceed as necessary.