Exhaust - Moan/Vibration At 2,100 RPM
91ford20
Article No.
91-13-6
06/26/91
^ EXHAUST - 3.8L - "MOAN" AT 2100 RPM
^ NOISE - "MOAN" AT 2100 RPM - 3.8L
^ VIBRATION - 3.8L - AT 2100 RPM
FORD: 1989-91 THUNDERBIRD
LINCOLN-MERCURY: 1989-91 COUGAR
ISSUE: An exhaust moan or vibration may occur at about 2100 RPM when the vehicle is in neutral or in gear (50-55 MPH in Drive, 70-75 MPH in O/D). This condition is induced by the engine.
ACTION: Install an exhaust system damper (F1SZ-5F240-A) and patch shield (F1SZ-9B007-A) to the fuel tank heat shield to correct the exhaust moan or vibration condition. Refer to the following procedure for service details.
Figure 1:
REMOVAL
1. Raise the vehicle on a hoist.
2. Remove the cross brace, Figure 1.
3. Remove the nuts attaching the muffler to the
resonator, Figure 1. Refer to the 1990
Thunderbird/Cougar Shop Manual, Section
26-01, for removal details.
Figure 2:
4. Remove the muffler assembly from the vehicle.
5. Remove the side rail exhaust hanger and save
it for later use, Figure 2.
Figure 3:
6. Remove the fuel tank heat shield attaching screws and remove the shield, Figure 3.
Figure 4:
7. Using the patch shield as a template, proceed
as follows:
a. Position the patch shield to the fuel tank
heat shield as shown in Figure 4.
b. Place the patch shield so that the distance is 5-5/8" (142.875 mm) from the middle rivet hole in the patch shield to the screw hole in the top of the heat shield, Figure 4.
8. Draw an outline of the patch shield onto the heat shield.
9. Mark the three (3) rivet holes.
10. Remove the patch shield. Draw the trim line 3/4" (19.05 mm) inside of the existing outline from Step # 8.
11. Cut along the trim line with a die grinder or equivalent.
12. Drill the three (3) 3/16" (5 mm) rivet holes where marked.
13. Install the patch shield (F1SZ-9B007-A) to the heat shield with 3/16" (4.763 mm) blind rivets (384432-S, included with the patch shield).
^ The rivets must be installed from the top pointing down.
^ After installation, the button side of the rivet should face the fuel tank.
^ The flared side of the rivet should face the exhaust pipe.
CAUTION: THE PATCH SHIELD MUST BE INSTALLED ON THE FUEL TANK HEAT SHIELD TO MAKE THIS TOTAL REPAIR EFFECTIVE.
INSTALLATION
1. Install the fuel tank heat shield/patch shield combined assembly.
Figure 2:
2. Install the side rail exhaust hanger, Figure 2.
NOTE: THE EXHAUST SYSTEM SHOULD BE COMPLETELY NEUTRALIZED PRIOR TO INSTALLING THE EXHAUST SYSTEM DAMPER. THE # 3 TRANSMISSION CROSSMEMBER AND EXHAUST MOUNT, TENDS TO BE BIASED TO THE DRIVER'S SIDE. NEUTRALIZING THIS AREA IS CRITICAL.
3. Install the muffler assembly and tighten to specification. Refer to the 1990 Thunderbird/Cougar Shop Manual, Section 26-01, for service details.
4. Remove the nuts from the U-bolts on the damper assembly (F1SZ-5F240-A).
Figure 5:
5. Position the damper to the exhaust pipe with the U-bolts to the rear of the vehicle, Figure 5.
6. Be sure that a clearance of 3/4" (19.05 mm) exists on all sides of the damper to avoid rattles, Figure 5.
7. Tighten nuts to 25-35 lb.ft. (34-47 N-m).
Figure 1:
8. Install cross brace, Figure 1.
9. Start vehicle and check for rattles.
PART NUMBER PART NAME CLASS
F1SZ-5F240-A Exhaust System Damper BG
F1SZ-9B007-A Patch Shield With Attaching BG
Rivets
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under Basic Warranty Coverage
OPERATION DESCRIPTION TIME
911306A Install Patch Shield And 1.7 Hr.
Damper
DEALER CODING
BASIC PART NO. CONDITION CODE
5F240 56
OASIS CODES: 403000, 703000, 702000