Worried About Nothing
Owners of 2009-2013 Buick Enclave vehicles equipped with 3.0L or 3.6L VVT direct injection V6 engines may comment about a clicking/ticking noise during cold starts.
The 3.0L and 3.6L SIDI engines use a direct injection fuel system that operates at very high fuel pressures. A direct injection fuel system produces a rapid clicking and ticking sound that can be heard from the engine compartment.
The sound is more evident when outside the vehicle or when the hood is open. The sound is more noticeable during idle and is more frequent during a cold start, but lessens once the engine is warm.
The rapid ticking noise on cold start is the fuel pump (located on the rear of the left cylinder head) building up high fuel pressure. When engine warmup is complete, the high pressure fuel pump will continue to click at a lower rate of approximately one tick per second at idle.
The clicking sound is the fuel injectors pulsing on and off under high fuel pressure. The sound is a normal characteristic of a direct injection fuel high pressure system. The noise does not indicate a need to replace the fuel pump or injectors.