Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Valve Train Analysis
The following inspection is used to diagnose valve train concerns.
Valve Train Analysis - Valve Cover Removed
Check for damaged or severely worn parts rocker arm assemblies and push rods.
Valve Train Analysis - Valve Springs
- Check for broken or damaged parts.
Valve Train Analysis - Valve Spring Retainer and Valve Spring Retainer Keys
- Check for correct seating of the valve spring retainer key on the valve stem and in valve spring retainer.
- Check for correct seating on the valve stem.
Valve Train Analysis - Valves and Cylinder Head
- Check for plugged oil drain back holes.
- Check for worn or damaged valve tips.
- Check for missing or damaged guide-mounted valve stem seal.
- Check for damaged hydraulic lash adjuster.
- Check installed valve spring height.
- Check for missing or worn valve spring seats.
Valve Train Analysis - Camshaft Lobe Lift
- Preform visual inspection. Check for damaged or severely worn parts and correct assembly.
- Remove the glow plugs. Refer to: GLOW PLUGS .
- Remove the rocker arm assemblies for the affected cylinders. Refer to: Rocker Arm .
- Install the Dial Indicator Gauge with Holding Fixture so the needle tip of indicator is on top of the push rod.
- Rotate the crankshaft using a breaker bar and socket attached to the crankshaft pulley retaining bolt. Rotate the crankshaft until the base circle of the camshaft lobe is reached.
- Zero the Dial Indicator Gauge. Continue to rotate the crankshaft until the high lift point of the rocker arm is in the fully raised position (highest indicator reading).
- To check the accuracy of the original indicator reading, continue to rotate crankshaft until the base circle is reached. The indicator reading should be zero. If zero reading is not obtained, repeat the measurement.
- If the lift on any lobe is below specified service limits, install a new camshaft and valve tappets. Refer to: Specifications .
- Install the rocker arm assemblies. Refer to: Rocker Arm .
- Install the glow plugs. Refer to: GLOW PLUGS .
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.