Engine - Lower End Tapping Noise
NO: 09-04-94GROUP: Engine
DATE: Apr. 8, 1994
SUBJECT:
5.9L Lower Engine Tapping Noise
MODELS:
1989 - 1990 (AB) Ram Van/Wagon
1988 (B) Ram Van/Wagon
1989 - 1990 (AD) Ram Pickup/Ram Cab & Chassis
1988 (D) Ram Pickup/Ram Cab & Chassis
NOTE:
THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH A 5.9L ENGINE THAT WERE BUILT IN 1990 OR PRIOR TO 1990.
SYMPTOM/CONDITION:
A lower engine tapping sound may occur following a service repair to a 5.9L engine. This engine repair would have involved the replacement of one of the following components: a short block, a connecting rod, or a connecting rod bolt. The tapping sound will occur when the original oil pan is reused during this service repair.
DISCUSSION:
A 1990 mid-model year change was made to the connecting rod bolt. The end of the bolt was increased in length by 10 mm. A tapping sound is caused by the end of the connecting rod bolt contacting the oil pan dipstick guide. Service replacement oil pans and late 1990 production 5.9L engine oil pans have the oil dipstick guide shifted forward toward the front of the oil pan. This allows for the necessary bolt-to-oil pan clearance. Older oil pans may require the following procedure to be performed (Refer to Item A in Figure 1).
DIAGNOSIS:
The origin of the tapping-like noise will come from the right side of the oil pan. The noise can be further localized to the front, top corner area of the oil pan. The technician will be able to localize this tapping noise with his ear and his hand. The technician may also notice a noise and interference as he rotates the engine by hand.
REPAIR PROCEDURE:
This bulletin involves the modification of the oil pan dipstick guide, which is located inside the engine oil pan.
NOTE:
THE TECHNICIAN SHOULD PERFORM THIS PROCEDURE DURING HIS ENGINE ASSEMBLY PROCESS AND WHILE THE OIL PAN IS STILL REMOVED FROM THE ENGINE.
1). With the oil pan already removed from the engine, locate the oil pan dipstick guide.
2). If the engine tapping noise had been present, there should be evidence on the dipstick guide of contact by the end of the connecting rod bolt.
3). Dent the oil dipstick guide with a hammer and punch so that the rear most corner of the guide is moved closer to the side of the oil pan (Refer to Item B in Figures 1 and 2).
4). The indentation should move the rear corner area of the guide 1/8" closer to the side of the oil pan, thus reducing the space between the oil pan wall and the dipstick guide. The indentation should extend down a 1/4" from the top edge of the guide and in a 1/4" from the rear corner edge of the guide.
5). After the guide is revised and the oil pan is installed, make sure that the oil dipstick installs properly into the dipstick tube and oil pan guide.
POLICY: Information Only