Engine - Knock Noise From Lower Front On Acceleration
Article No.93-23-15
11/10/93
^ ENGINE - 4.6L - "KNOCK" NOISE FROM LOWER FRONT OF ENGINE DURING LIGHT TO MODERATE ACCELERATION
^ NOISE - "KNOCK" - FROM LOWER FRONT OF ENGINE DURING LIGHT TO MODERATE ACCELERATION - VEHICLES WITH 4.6L ENGINE
FORD:
1991-92 CROWN VICTORIA
LINCOLN-MERCURY:
1991-92 GRAND MARQUIS, TOWN CAR
ISSUE:
A "knocking" noise, from the lower front of the engine, may be heard during light to moderate acceleration. It usually occurs when stopped or when accelerating following a stop. The noise is most pronounced at light brake torque (about 1200 RPM) after the engine has warmed to normal operating temperature. The "knocking" noise can be greatly reduced by removing the Front End Accessory Drive (FEAD) belt and operating the vehicle as previously described.
ACTION:
Install an idler/tensioner bracket and accessory drive belt service kit which includes a new idler/tensioner bracket and new accessory drive belt to correct this condition. Refer to the following procedure for service details.
1. With the vehicle parked in a well ventilated area...
a. Set the parking brake.
b. Block all wheels to prevent sudden movement of the vehicle.
WARNING:
MAKE SURE NO ONE IS STANDING IN FRONT OF THE VEHICLE.
2. With the engine warmed to normal operating temperature..
a. Place transmission in DRIVE and brake torque engine to about 1200 RPM.
b. Listen for low-end knock noise at front of engine.
3. Once the noise has been identified, remove the accessory drive belt and repeat Step 2. The noise should diminish greatly.
CAUTION:
DO NOT ALLOW PROLONGED OPERATION OF THE ENGINE (MORE THAN 2 MINUTES) WITHOUT THE ACCESSORY DRIVE BELT INSTALLED BECAUSE OVERHEATING MAY OCCUR.
4. Install the idler/tensioner bracket and accessory drive belt service kit (F2AZ-6G01-A). Refer to Instruction Sheet # 6476, included in the kit, for the installation procedure.
Obtain an Authorized Modifications Decal and list the date, dealer number, and summary of alterations performed. Select a prominent place adjacent to the Vehicle Emission Control Information Decal suitable for installing the Authorized Modifications Decal. Clean the area, install the decal, and cover it with a clear plastic decal shield.
Parts Block
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS:
Eligible Under Bumper To Bumper Warranty Coverage For 1991 Lincoln Town Car And All 1992 Model Vehicles, Basic Warranty Coverage For 1991 Crown Victoria/Grand Marquis
OPERATION DESCRIPTION TIME
932315A Remove and Replace Idler 0.6 Hr.
Assembly and Belt
DEALER CODING
BASIC PART NO. CONDITION CODE
6B209 56
OASIS CODES:
490000, 497000, 702000, 702100