Momentarily Noisy When Engine is Started.

This condition is normal. Oil drains from the lifters, which are holding the valves open when the engine is not running. It will take a few seconds for the lifters to fill after the engine is started.

Incorrect/faulty oil filter.

Intermittently Noisy on Idle Only; Disappearing When Engine Speed is Increased.

Dirt in hydraulic lifter or low oil pressure.

Disassemble and clean.

Replace lifter.

Pitted or damaged check valve.

Replace the hydraulic lifter.

Noisy at Slow Idle or With Hot Oil; Quiet at High Engine Speeds or with Cold Oil.

High leak down rate or low oil pressure.

Replace the hydraulic lifter.

Noisy at High Speeds, Quiet at Low Speeds.

High Oil Level: Oil level above the MAX mark allows crankshaft counterweights to churn the oil into foam. When foam is pumped into the lifters, they will become noisy since a solid column of oil is required for proper operation.

Drain oil to proper level.

Low Oil Level: Oil level below the MIN mark allows the oil pump to pump air at high speeds which result in noisy lifters.

Add oil as needed.

Engine Starts Normally, But Stalls within Five Minutes. Engine Has Low Compression During Initial Cranking after Stall.

Low compression due to hydraulic lifter(s) being pumped up.

Incorrect viscosity oil. Refer to Owner's Handbook/Service Manual recommendations.