Loud tapping sound coming from my engine while the car is idling

Hi,

Is it possible for you to record the sound and upload it for me to hear? When you replaced the rockers, did you inspect the camshafts? Did you adjust lash?

Here are the directions. Let me know if this was done.

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2004 Chrysler Pacifica V6-3.5L VIN 4
Procedures
Vehicle Engine, Cooling and Exhaust Engine Camshaft, Lifters and Push Rods Lifter / Lash Adjuster Service and Repair Procedures
PROCEDURES
STANDARD PROCEDURE - HYDRAULIC LASH ADJUSTER BLEEDING

Use this procedure to manually bleed aerated oil from the lash adjuster and remove sponginess.
1. Run the engine, bringing it to operating temperature in order to freshly pressurize and warm the valvetrain system oil supply.
2. Remove cylinder head cover(s).

Pic 1

3. Ensure the rocker arm is positioned on the base circle of the cam (Fig. 54). Rotate engine as necessary.
4. For intake rocker arm positions:

pic 2

a. Adjust Special Tool 8351 Release Probe's gauge pin to extend approximately 20 mm (0.787 inch). Then, carefully insert the release probe gauge pin into the lash adjuster service access hole (Fig. 55).

CAUTION: If probe tip breaks off within the lash adjuster, replace the affected rocker arm.

B. Gently unseat lash adjuster's internal check ball.
C. While the internal check ball is held unseated, press the rocker arm into the valve tip, allowing the lash adjuster to fully collapse. Hold this fully collapsed position for about one second, or longer.
D. Slowly release the rocker arm, thereby allowing the lash adjuster to extend, which in turn refills the high pressure chamber with non-aerated oil.
E. Remove probe to allow check ball to seat.
F. Recheck for sponginess. If the lash adjuster sponginess is not completely or nearly eliminated, then repeat procedure.
G. If the spongy condition cannot be removed, replace effected rocker arm(s).
5. For exhaust rocker arm positions:
a. Adjust Special Tool 8351 Release Probe gauge pin to extend approximately 20 mm (0.787 inch). Then, using two release probes, carefully insert gauge pins into the lash adjuster service access holes (Fig. 55).

CAUTION: If probe tip breaks off within the lash adjuster, replace the affected rocker arm.

B. Gently unseat BOTH lash adjuster's internal check ball at the same time.
C. While the internal check ball is held unseated, press the rocker arm into the valve tip, allowing the lash adjuster to fully collapse. Hold this fully collapsed position for about one second, or longer.
D. Slowly release the rocker arm, thereby allowing the lash adjuster to extend, which in turn refills the high pressure chamber with non-aerated oil.
E. Remove probes to allow check balls to seat.
F. Recheck for sponginess. If the lash adjuster sponginess is not completely or nearly eliminated, then repeat procedure.
G. If the spongy condition cannot be removed, replace effected rocker arm(s).
6. Install cylinder head cover(s).

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Let me know.

Take care,
Joe

Hi,

As far as the bearing, that what it sounds like. Also, is the oil pressure staying around 20 psi? If so, that is actually good. Now if it is a bearing, that will not change the compression. It will knock but the piston isn't affected enough to change compression.

I hate to say it, but at this point, I feel either that engine needs rebuilt or replaced. Chances are it would be less expensive to replace it with a good used one.

By the way, a main bearing will cause low oil pressure. One rod bearing won't. I have a feeling the problem is one of the main bearing in the crank shaft.

Let me know if you have other questions or need help with anything.

Joe

Hi,

Yes, it is possible. However, it may not be just the bearing at this point. The crankshaft may now need replaced. Also, normally when replacing one, they are all done. In my opinion, you may be better off getting a good used engine simply because cost can go up really fast on repairing this one.

Please let me know if I can help or if you have other questions.

Take care,
Joe

You are very welcome. Please feel free to come back anytime.

Take care,
Joe