ENGINE - MUSTANG COBRA - TICK NOISE FROM ENGINE - COBRA VEHICLES EQUIPPED WITH ENGINES BUILT BEFORE 11/1/2002 ONLY
Publication Date: May 23, 2003
Some 2003 Mustang Cobra vehicles with engines built before 11/1/2002 may exhibit an unusual engine tick noise that is present at all temperatures during idle. This noise may be due to valve guide wear in the left bank cylinder head. Guide wear manifests itself as a tick noise which can be heard at the rear of LH head, through LH catalyst, at the LH front wheel well and may not be heard with the hood open.
Use the diagnostic procedures listed in this article to evaluate the vehicle condition and replace the cylinder head if applicable. Refer to the following Service Procedure for details.
THIS REPLACEMENT CYLINDER HEAD WILL NOT IMPROVE OR REDUCE PERFORMANCE.
In order to diagnose noise, the following items must be checked.
Verify noise by placing a stethoscope on the back of the left head near the exhaust ports.
Verify that the noise is heard in the left side exhaust system (left side wheel well or catalytic converter, from underneath the vehicle).
Try to isolate the noise by canceling the cylinders, by unplugging the injectors one at a time (start with #8 cylinder).
Verify that there are no exhaust manifold leaks.
Check to make sure that the camshaft spacers are in place. If not, install cam spacers (per Workshop Manual Section 303-01C) and retest vehicle.
Check for proper cam sprocket bolt torque, retorque to spec listed in the Workshop Manual Section 303-01C.
Check for spongy lash adjusters (refer to Section 303-00 in the corresponding Workshop Manual).
Verify that the timing chain tensioner pin has been removed.
If the above diagnostics does not eliminate the noise while the cylinders are cancelled, and the engine was built prior to 11/1/2002, replace the left side cylinder head and cam assembly with Part Number 3R2Z-6049-GA. Refer to Workshop Manual Section 303-01C for cylinder head replacement procedures.
Cylinder Head And Cam Assembly - Left - Cobra Only