Our Jeep has developed an engine clatter at idle speed sounds like a loud tappet with another strange noise that comes and goes at the same time. Not sure if they are manual or hydraulic valve lifters on this engine.
When cold it sound quite noisy from outside the vehicle it will mostly disappear when the engine gets up to temperature. When re-started when hot the noise is usually absent but will return when cold.
Any pointers please it does not sound like a timing chain clatter in my view though I could be wrong.