My car starts with a rattling sound, but then it goes away after driven a bit.
Hi. It's difficult for me to say without hearing the noise firsthand, but there are a couple things that come to mind. The first is the hydraulic valve lash adjusters. The lash adjusters use oil pressure to keep the lash between the rocker arm and valve at a constant rate. When the engine is cold, it sometimes takes oil awhile to reach the adjusters. As a result, you have a rattling or tapping noise when the engine is cold. This is a common problem with the vehicle you have. The second thing that comes to mind is an exhaust leak at the manifold. This is more noticeable when the engine is cold and often goes away as the engine warms up. This is because the exhaust manifold metal expands. My best advice is to have a trained mechanic, such as one from YourMechanic, listen to your vehicle's noise.
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