4.6L (LH2) Engine With a Cold Start, Ratcheting/Clicking Noise Lasts - kw camshaft click cold

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.

Some 04 Cadillac SRX, XLR 4.6L (LH2) Northstar engines may experience a cold start, loud ratcheting type/ clicking type noise that lasts 1 -2 seconds. The noise will be heard from the front of the engine. The vehicle usually has to set for a minimum of 1-2 hours sometimes up to an 8-hour soak is necessary to reproduce the noise. ( the oil has to drain out of the phaser to duplicate this condition)

.

The 04 Cadillac SRX, XLR 4.6L (LH2) Northstar engine cold start, loud ratcheting type/ clicking type noise may be caused by the cam phaser lock pin failing to properly engage.

To check for the cause of the cold start, loud ratcheting type/ clicking type noise concern:

1. Remove both camshaft covers (no specific engine soak time is required as the oil pressure will drained off during the time to remove both camshaft covers).
2. Using an open-end wrench on each of the four camshafts try to rotate the camshaft in both a clockwise and counter clockwise direction. Slight rotation (less that 3 degrees) will occur due to slack in the drive chains.
3. If any of the camshafts rotate up to approximately 25 degrees, the locking pin on that cam phaser is not engaging. This non-locking cam phaser should be replaced.

Cam Phaser Part numbers are:

LH Exhaust - 12567415

LH Intake - 12567417

RH Exhaust - 12567414

RH Intake - 12567416

Note At this time do not remove the phaser bolt from the phaser, keep the phaser together and put it in a plastic bag to contain the sediment. The phaser is required to be shipped back to the WPC.

4. If none of the four camshafts rotate in either direction it's possible that some sediment was disrupting the locking pin and now it has been dislodged. The camshaft covers should be reinstalled and the noise concern should be reevaluated.

The camshaft covers gasket p/n if necessary is 12576394 and 12576395.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not automatically be used for other vehicles with similar symptoms.

.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

.

(2004 CADILLAC SRX 4.6L (LH2) ENGINE) and (2004 CADILLAC XLR 4.6L (LH2) ENGINE)