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TSB 09-10-94

3.9L MPI Excessive Valvetrain or Tappet Noise

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Date: Jan. 19, 2001

Models: 1994 - 2001 (BR/BE) Ram Truck

1992 - 1993 (AB) Ram Van/Wagon
1992 - 1993 (AD) Ram Pickup/Ram Cab & Chassis
1992 - 1993 (AN) Dakota/Dakota Cab & Chassis
1994              (AB) Ram Van/Wagon (with 12th digit of the VIN coded 5)

NOTE: THIS Bulletin APPLIES TO VEHICLES EQUIPPED WITH A 1992-1993 MPI 3.9L ENGINE AND 1994 (AD) VEHICLES WITH A "5" AS TIE 12th DIGIT OF ITS VIN.

Symptom/Condition:

The engine my exhibit tappet-like noise(s) and/or excessive general valvetrain noise. The tappet-like noise may move from one tappet location to another. The tappet-like noise nay also move to another tappet location when tappets have been replaced.

NOTE:  DESIGN CHANGES TO THE 1994 3.9L ENGINE HAVE CORRECTED THIS CONDITION.

Diagnosis: 

The technician can diagnose for a tappet noise by running the engine at idle with the valve covers removed. A noisy tappet will cause the valve spring and/or rocker arm to vibrate or feel rough to the touch while it is in operation. Generally, if there is more than one tappet which is noisy, than the problem is not tappets.

A worn oil pump drive gear my cause engine valvetrain noises (light knock or tapping sound) at the rear of the engine. This noise should not be confused with a tappet noise. Refer to Technical Service Bulletin 18-08-93 titled "Engine Buck, Surge or Noise - Oil Pump Drive Gear Wear".

The technician may have experienced that the tappet noise may have "moved" to a different tappet location following a previous tappet service replacement.

Parts Required:

1      04778880      Timing Chain and Sprocket Kit
1      53020284      Timing Cover Gasket
1      82300234      Mopar RTV Sealant

Repair Procedure: 

This bulletin involves the replacement of the link type timing chain and sprockets with a double roller type timing chain and sprockets.

1. With the timing cover removed, align the old timing chain sprockets before removal from the engine.

2. Remove the old timing chain and both sprockets.

3. Remove the old timing cover gasket.

4. Place both new camshaft sprocket and crankshaft sprocket on the bench. Align both sprocket marks on an exact imaginary center line through both camshaft and crankshaft bores.

5. Place the new double roller timing chain around both new sprockets.

6. Slide both sprockets evenly over their respective shafts and use a straightedge to check alignment.

7. Install the camshaft bolt. Torque the bolt to 68 NM (50 ft. lbs.).

8. Use a small amount of Mopar RTV Sealant, or equivalent, at the joint between the timing chain cover gasket and the oil pan gasket.

9. Using a new timing cover gasket, carefully install the timing cover to avoid damaging the oil pan gasket. Finger tighten the attaching bolts.

10. Torque the timing cover bolts to 41 Nm (30 ft. lbs.) and the oil pan bolts to 24 Nm (18 ft. lbs.).

Notes: 

Policy:    Reimbursable within the provisions of the warranty.

Time Allowance:

Labor Operation No:
09-10-05-90	1992-1994 AB 1992-1993 AD, AN	2.4 Hrs. 2.3 Hrs.
09-10-05-61	1992-1994 AD & 1992-1993 AD, AN (P/S Equipped) .	0.2 Hrs.
09-10-05-64	1992-1994 AD (A/C Equipped) 1992-1993 AD, AN (A/C Equipped)	0.2 Hrs. 0.4 Hrs.

Failure Code:

68

Noisy