Overhaul - 3.8L Engine: NVH Chrysler Pacifica CS

VALVE TRAIN NOISE

To determine source of valve train noise, operate engine at idle with cylinder head covers removed and listen for source of the noise.

Note. Worn valve guides or cocked springs are sometimes mistaken for noisy lifters. If such is the case, noise may be dampened by applying side thrust on the valve spring. If noise is not appreciably reduced, it can be assumed the noise is in the tappet. Inspect the rocker arm push rod sockets and push rod ends for wear.

Valve lifter noise ranges from light noise to a heavy click. A light noise is usually caused by excessive leak-down around the unit plunger which will necessitate replacing the lifter, or by the plunger partially sticking in the lifter body cylinder. A heavy click is caused either by a lifter check valve not seating, or by foreign particles becoming wedged between the plunger and the lifter body causing the plunger to stick in the down position. This heavy click will be accompanied by excessive clearance between the valve stem and rocker arm as valve closes. In either case, lifter assembly should be removed for inspection.

Scheme 285

1. Remove the cylinder head(s). (Refer to «CYLINDER HEAD»(ref-245455-S11415369272006110200000) )
2. Remove the yoke retainer and aligning yokes. (Scheme 285)
3. Remove the hydraulic lifters. If necessary use Special Tool C-4129, or equivalent to remove lifters from bores. If lifters are to be reused, identify each lifter to ensure installation in original location.

Scheme 286

1. Lubricate the lifters with engine oil. NOTE: Position the lifter in bore with the lubrication hole facing upward. (Scheme 286)
2. Install the hydraulic lifters with the lubrication hole facing upward towards middle of block. (Scheme 286) Install lifters in original positions, if reused. 1 - YOKE RETAINER 2 - BOLT - YOKE RETAINER 3 - ALIGNING YOKE 4 - HYDRAULIC LIFTER
3. Install lifter aligning yokes. see scheme 90
4. Install yoke retainer and torque screws to 12 N.m (105 in. lbs.). see scheme 90
5. Install the cylinder heads. (Refer to «CYLINDER HEAD»(ref-245455-S11415369272006110200000) )
6. Start and operate engine. Warm up to normal operating temperature.

Scheme 287

The nodular iron camshaft is mounted in the engine block and supported with four steel backed aluminum bearings. (Scheme 287) A thrust plate, located in front of the first bearing, is bolted to the block and controls the camshaft end play.