ENGINE NOISE TICKING EXCESSIVE ROD SIDE CLEARANCE

CONDITION

Some 3.8L and 4.1 L V-6 engines may experience a light ticking type noise, which will normally be heard just above idle and under a light load (car in gear) condition. This noise will be most pronounced at the rear of the front wheel opening. Disconnecting the EST harness at the distributor may decrease the noise. Also, it can generally be shorted out on the number 5 cylinder.

CORRECTION

When diagnosing this type of noise, the piston rod side clearance (fore and aft movement) at crankshaft pin journals no. 1, 3 and 5 cylinders, should be checked. Using a feeler gage, check the clearance between the piston rod and the counter balance area of the crankshaft (Refer to Fig. 1). The clearance check should be made in more than one place on the crankshaft and care should be taken to be sure feeler gauge is down all the way onto the crankshaft and not sitting on top of the narrow raised thrust surface adjacent to piston rod. If the clearance exceeds .015" (.381 mm), replace only the rod(s) having excessive clearance with a new rod, part no. 25516444.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.