D150 1/2 Ton Pickup 2WD V6-239 3.9L VIN X FI (1988)
Lifter / Lash Adjuster: All Technical Service Bulletins
Engine - Tappet Noise
No.
09-08-87
(C8-09)
P-4733
Date:
December 28, 1987
Index:
ENGINE
Subject:
Tappet Noise
Models:
1988 Equipped With 3.9L or 5.2L Engine
SYMPTOM/CONDITION
Some vehicles equipped with "LA" family engines (3.9L or 5.2L) built prior to October 29, 1987, may exhibit tappet related noise. This condition can be
identified as a single or multiple ticking noise originating in one or both cylinder heads. The noise is due to air trapped in the tappet. The causes usually
involve one or more of the following:
^
Insufficient oil fill of tappet
^
1988 roller tappet socket/solid push rod leak condition
^
High clearance/high dry lash
^
Seized/sticky/defective tappet
^
Insufficient oil supply to tappet
DIAGNOSIS
The vehicle should be started cold and operated in park or neutral at idle. Isolate the noise for bank and approximate cylinder location. Remove the
cylinder head covers on the noisy bank(s) one at a time. Check the rocker shaft fastener torques. If loose, retorque and re-evaluate the engine noise. Pin
point the noise location to cylinder(s) and valve(s) by pushing on each rocker arm individually while the engine is running, noting changes in the noise
produced. Note these tappets for future reference.
Operate engine for 30 minutes at varying rpms (900 - 2000), or until noise is gone. Restart engine from cold condition. If noise is still evident, follow
directions under the repair procedures.
PARTS REQUIRED
Push Rod
PN 4483721
REPAIR PROCEDURE
This procedure involves bleeding and/or replacing the hydraulic tappets and replacing the push rods.
1.
Remove cylinder head covers.
2.
Remove and discard the push rods from the engine. The removed push rods should be of solid rod construction.
3.
Using one of the removed push rods, insert it through the push rod hole in the cylinder head and push down on the push rod socket of each roller
tappet. If the roller tappet has entrapped air, the push rod socket will move within the tappet body. Note which roller tappets are "soft." Only these
tappets need to be filled manually.
WARNING:
IF, WHEN LOADED, THE PUSH ROD SOCKET DOES NOT MOVE IN THE TAPPET BODY, AND THE PUSH ROD SOCKET IS BELOW
THE RETAINING CLIP IN THE BODY, THE ROLLER TAPPET IS PROBABLY DEFECTIVE AND REPLACEMENT IS NECESSARY.
