Engine - Vibration at Idle
Bulletin No.: 003/93Issued: 4/14/93
Revised:
Category
B
Applicable Model/s
1993 MX-6/626
(A/T Models)
Subject:
4-CYLINDER ENGINE VIBRATION
DESCRIPTION
Due to inherent characteristics of 4-cylinder engines, vehicles equipped with automatic transmissions will transmit vibrations and resonance into the vehicle's interior during idle. This is a normal characteristic resulting from transversely-mounted powertrain designs. However, some vehicles may exhibit a higher than normal amount of idle vibration and resonance.
Before performing the repair procedures listed in this bulletin, perform the following "Quick Checks" to determine if the level of vibration can be reduced effectively.
1. Compare the affected vehicle's vibration and resonance to one or more equally-equipped vehicle(s) from the dealer inventory. Perform this in "Drive" and "Reverse" with the air conditioner on.
2. Perform a visual inspection of Engine Mount No. 3 to verify it is centered in the bracket. Refer to Step 2 in the repair procedures of this bulletin for details.
3. Check base idle speed at normal operating temperature and if necessary, set to 700-750 rpm per Section B of the applicable Workshop Manual.
If the results indicate the level of vibration to be equal to other equally-equipped vehicle(s) and/or the Engine Mount No. 3 is centered in the bracket, performing the repair procedures in this bulletin will not reduce idle vibration. Do not attempt further repairs and advise the vehicle owner of the characteristics of transversely-mounted 4-cylinder powertrains.
If the affected vehicle's level of vibration is comparably greater than the other vehicles or if Engine Mount No. 3 is not centered, perform the following repair procedures to reduce and isolate the idle vibration.
REPAIR PROCEDURE
Located in this bulletin.
1. Place the vehicle on a hoist. Using a 17 mm socket, loosen the center bolt that goes through Engine Mount No. 2. Figure 1.
2. Check the clearance of Engine Mount No. 3 against the mounting bracket. There should be clearance between the rubber mount and the bracket with electrical load and while in drive and reverse. If the rubber mount contacts the bracket, remove the rubber mount and shave (with a hacksaw or grinder) 1.0 mm off both sides of the rubber as shown in Figure 2.
3. Remove the air cleaner. Remove the ground connector on the Engine Mount No. 4. Loosen the three bolts (marked as "A"). Figure 3. Use a pry bar to hold the bracket in place and to center the rubber between the bracket. Tighten the bolts that were previously loosened to 67-93 N-m (6.8-9.5 kg-m, 50-68 ft.lb.). Reconnect the ground connector and install air cleaner.
4. Loosen the 2 nuts holding Engine Mount No. 2 to the engine mount member. Engine Mount No. 2 will move and will align itself. Retorque the 2 nuts to 75-104 N-m (55-77.3 ft.lb.). Figure 4.
5. Torque the Engine Mount No. 2 center bolt to 86-116 N-m (63-86 ft.lb.). Figure 5.
6. Run the engine until warm and check for vibration. Check for interference from any components in the engine area that can be a path of vibration from the engine to the body. Ensure that the radiator is centered and the lower radiator mount is fully seated.
WARRANTY INFORMATION
(Applies to vehicles covered under warranty.)
Warranty Type Code: A
Customer Comment Code: 83
Damage Code: 9H
Part No. of Main Cause: GA2A 39 050
Operation No: YY0098RX
Labor Hours: 0.2 Hrs. (inspection only) 0.8 Hrs. (includes inspection and repair)