MPV 4WD V6-3.0L SOHC (1990)
Technical Service Bulletin # B00198
Date: 980223
Hydraulic Lash Adjuster - Noise
Bulletin No.: 001/98
Issued: 02/23/98
Revised:
Category
B(01)
Applicable Model/s
1989 - 97 MPV
With JE Engine
Subject
HLA NOISE
APPLICABLE MODELS
1989 - 97 MPV with a JE engine.
NOTE:
See Repair Procedure for applicable VIN ranges.
DESCRIPTION
HLA noise may be heard after a cold engine start and continue to be heard for a period of 30 seconds to a few minutes. HLA noise is most likely to occur
after long term storage. Three HLA related noise patterns (A, B and C) are illustrated above.
NOISE PATTERN "A" - This noise pattern is caused when the depth of the HLA plunger stroke is increased. The increase in stroke depth is caused by
wear between the rocker arm and the rocker arm shaft. During cold starts, insufficient oil is supplied to gap created by the wear and air enters the HLA
resulting in noise.
To prevent this noise pattern, the rocker arm is redesigned to reduce the HLA installation depth which reduces the HLA plunger stroke.
NOISE PATTERNS "B" and "C" - These noise patterns are related to HLA plunger spring and 0-ring deterioration over time. As a result, the HLA
holding force decreases and allows oil pressure to push the HLA out of position. When the HLA is pushed out, a clearance is created between the rocker
arm and the HLA seat.
To prevent the HLA from being pushed out of position, the rocker arm shaft oil passage has been changed to decrease oil pressure supplied to the HLA.
