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.
Rocker Arm Oil Control System Description: Notes
The 3.5L RPO-L66 engine has a high speed cam system that increases engine output above 4,400 RPM. The increase in power is possible because valve lift is significantly increased between 4,400 and 6,500 RPM. A second camshaft lobe with a high lift profile is ground into each camshaft, alongside the low-medium speed lobes. In order to use the high speed cam only when desired, the engine utilizes a rocker arm oil control system. The system uses unique rocker arms that are hydraulically operated and electronically controlled.
| Callout | Component Name |
|---|---|
| 1 | Synchronizing Pistons |
| 2 | Low-Medium Speed Intake Rocker Arms |
| 3 | High Speed Intake Rocker Arm |
| 4 | Exhaust Rocker Arms |
| 5 | Camshaft |
| 6 | Exhaust Valves |
| 7 | Intake Valves |
The three intake rocker arms (2 and 3) ride on rocker arm shafts as do the two exhaust rocker arms (4). The rocker arm shafts supply engine oil to the rocker arms. When the flow of oil to the rocker arms increases, the synchronizing pistons (1) move and lock the three rocker arms together. With all three rocker arms locked together, the high speed cam lobe opens and closes the intake valves (7).
The flow of oil thru the rocker shafts to the rocker arms is controlled by the rocker arm oil control solenoid. A rocker arm oil pressure switch monitors the operation of the oil control solenoid. The rocker arm oil control solenoid (1) and the oil pressure switch (3) are located near the engine oil filter (2) on the lower right rear corner of the engine.
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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.