WORKHORSE CUSTOM CHASSIS
Service Manual
W SeriesWCC
SECTION
6.2
PAGE
99
Engine Mechanical
W Series Chassis
TOC
© 2006 WorkhorseCustom Chassis — All Rights Reserved
UPPER ENGINE NOISE, REGARDLESS OF ENGINE SPEED
Cause Correction
Low oil pressure 1. Perform an oil pressure test. Refer to Oil Pressure Diagnosis and
Testing .
2. Repair or replace, as required.
Loose and/or worn valve rocker arm attachments 1. Inspect the valve rocker arm stud, nut, or bolt.
2. Repair or replace, as required.
Worn or damaged valve rocker arm 1. Inspect the rocker arm for wear or missing needle bearings.
2. Replace the valve rocker arms, as required..
Worn pushrod guide plate Replace, as required.
Bent or damaged push rod 1. Inspect the following components and replace, as required:
• The valve rocker arm
• The valve push rod
• The valve lifter
• The valve guide
• The piston
2. Inspect the top of the piston for valve contact. If the top of the piston
shows valve contact, replace the piston and pin assembly.
Improper lubrication to the valve rocker arms Inspect the following components and repair or replace, as required:
• The valve rocker arm
• The valve push rod
• The valve lifter
• The oil fi lter bypass valve
• The oil pump and pump screen
• The engine block oil galleries
Broken valve spring Replace the valve spring and spring shim.
Worn or dirty valve lifters Replace the valve lifters.
Stretched or broken timing chain and/or damaged sprocket teeth Replace the timing chain and sprockets.
Worn camshaft lobes 1. Inspect the camshaft lobes.
2. Replace the camshaft and valve lifters, as required.
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