Engine - Tapping Noise
Article No.97-17-13
08/18/97
^ ENGINE - 2.5L - "TAPPING" NOISE FROM REAR
CYLINDER HEAD CAMSHAFT FRICTION GEAR -
VEHICLES BUILT BETWEEN 4/16/92 AND 12/12/96
^ NOISE - "TAPPING" - COMING FROM REAR
CYLINDER HEAD - CAMSHAFT FRICTION GEAR
SPRING - VEHICLES BUILT BETWEEN 4/16/92 AND
12/12/96 WITH 2.5L ENGINE
FORD:
1993-97 PROBE
This TSB article is being republished in its entirety to correct a service part number.
ISSUE:
Some vehicles may have a tapping noise coming from the right rear cylinder head exhaust camshaft area directly behind the timing cover. The tapping noise starts during engine warm-up and the noise level can increase as the engine reaches normal operating temperature. In some cases the noise may begin to oscillate in 3 to 5 second intervals. This may be caused by the friction gear spring on the camshaft losing its tension and causing the noise.
ACTION:
Replace the camshaft friction gear spring and locknut with a revised friction gear spring and locknut which has more spring tension. Refer to the following Service Procedure for details.
SERVICE PROCEDURE
1. Verify where the noise is located by placing a stethoscope on the rear cylinder head directly behind the timing cover.
2. Remove the exhaust camshaft following the service procedure located in the appropriate Probe Service Manual.
NOTE:
FOLLOW THE REMOVAL PROCEDURES LISTED IN THE SERVICE MANUAL TO REMOVE THE CAMSHAFT, OTHERWISE THE CAMSHAFT MAY BE BENT AND RESULT IN A DIFFERENT NOISE WHEN REASSEMBLED.
3. Place the camshaft in a vise so that the matching mark is facing up.
NOTE:
BE SURE TO WRAP THE JAWS OF THE VISE WITH SOFT TOWELS TO PREVENT DAMAGE TO THE CAMSHAFT.
4. Loosen the locknut and remove the friction spring and friction gear. Be sure to note the direction of the friction gear before removal. The friction gear must be reinstalled in the same direction.
5. Clean the camshaft and friction gear.
6. Lubricate the friction gear with clean engine oil and reassemble using the revised Friction Spring (F72Z-6278-AA).
NOTE:
TORQUING THE LOCKNUT TO SPECIFICATION IS CRITICAL TO ASSURE THAT THE TENSION BETWEEN THE CAMSHAFTS REMAINS CONSTANT.
7. Install the revised Locknut (F72Z-6259-AA) and tighten the nut to 75-83 N.m (55-61 lb-ft). When tightening the nut, make sure gear teeth are aligned around the matching mark. This will make it easier to install the camshaft into the cylinder head.
8. Check camshaft runout according to the appropriate Service Manual procedures.
9. Reinstall the camshaft according to the appropriate Service Manual procedures.
PART NUMBER PART NAME
F72Z-6278-AA Friction Spring
F72Z-6259-AA Locknut
OTHER APPLICABLE ARTICLES: NONE
SUPERSEDES: 97-14-11
WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage
OPERATION DESCRIPTION TIME
971713A Replace Right Side 4.5 Hrs.
Camshaft Friction Spring
DEALER CODING
CONDITION
BASIC PART NO. CODE
6278 63
OASIS CODES: 497000, 499000, 702100