2013 Honda Fit - Failure after dealer visit

Another dumb question. Assuming the sound is coming from the engine why would the sound be non existent when the engine was cold. Does it have something to do with oil being denser at cooler temperatures?
Just slightly annoyed that the mechanic said that everything was normal instead of giving me an explanation of possible reasons for the odd sound.

Engine noises whuich change by temperature could be exactly what you say, the oil is more viscous when it is cold. Or it could be the dimensions of the parts change a little, cold metal contracts, hot metal expands. Valve noises due to overly loose valves are often are worse at first start up of the cold engine, not b/c the oil is thick, but b/c the oil pressure hasnā€™t risen to full pressure yet. You know the Car Talk brothers nicknames, Click and Clack? I believe thatā€™s a reference to the noise loose valves make.

Also consider that this noise was there all along, and you didnā€™t notice it. I had that problem w/a VW Rabbit, I did a repair and all of a sudden noticed a high pitched whining noise, esp during acceleration. Turned out it was there all along, before what I did, just the normal noise those type of fuel injectors make.

Iā€™ve gotten a ticking sound from a plug wire shorting out against something metal. Not enough to cause a miss but enough to make a sound. They had to take all of that apart for the head so maybe just check that the wires are routed away from metal parts the way they should be. But yeah wouldnā€™t hurt to have someone listen to it.

If it was valvelash, it wouldnā€™t change going uphill or at idle. Probably an exhaust gasket leaking when the engine heats up.

@anon86613489 posts a good idea above to consider exhaust noise as a possible culprit. Replacing the head involved monkeying w/ the exhaust system and the head/exhaust manifold gasket. The counterargument is that sort of noise (when listening from the engine compartment) to me sounds more like a pffft ā€¦ pfffft ā€¦ pffft sound , rather than a sharp click. If it is really bad leak it may sound like a firecracker, ā€œbangā€, again not like a click. Sometimes a length of old garden hose can be used as a stethoscope to narrow down where exactly the sound is coming from. That might provide another clue.

I am taking it to an independent shop tomorrow to have them look at it. My guess is that the honda tech took it for a drive, did not let it warm up enough then assumed I was hearing a loose jack in the rear of the car or something. It takes a good five minutes after the cold engine light icon disappears before the sound is noticeable. The fact that he or she was not making much money on the warranty repair and none on the test drive probably was a factor in how much time he or she wanted to spend on it.

  Seems as though from I have researched that mechanics are underpaid nowadays. Here is the sound which I think you can barely hear when I shift into second. There is alot of backround noise as well. Not sure that the iphone microphone does a very good job of picking up the sound.

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