XJ ( X351 ) 2009 - Onwards

2011 XJ 5.0 Engine Knock on Warm Restart

Old 08-16-2018, 11:22 AM
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Hi, my xj supersport is making exactly the same noise. I replaced the sc snout and water pump. Motor is quiet when stone cold but as soon as there is some temp it starts knocking. Another thread on here says if it kno ks when cold it's tensioners (makes sense) but quiet when cold and knocks when warm its actuators.

I juat don't know what actuators but apparently there are 4 of them, any ideas?

Old 01-06-2019, 07:07 AM
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Just wondering if there are any updates on this noise. My XFR has the same noise but still runs like a dream. Could it be a HP fuel pump.
Old 01-07-2019, 12:49 PM
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Mine still does it and everything is working fine. I really think its just a characteristic of the engine.
Old 01-07-2019, 07:26 PM
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My 2012 XJ S/c 5.0 sounded that way at 38K miles, when I bought it, and still does, at 60K miles. I asked the dealer about it when they were doing CPO warranty work last fall, and they said "that is how they sound". I have heard it described as a "tinny sounding engine", and cannot say I disagree. Doesn't affect the running, an any way, though.
Old 02-08-2019, 01:32 AM
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That noise I heard on the You Tube is at half crank or camshaft speed. It is a knock, not chain rattle.These are direct injection engines with a reputation of intake carbon build up. Perhaps it is carbon build up interference with the valve guides???
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