My car has 40K miles, and I've never heard anything unusual from under the hood. Yesterday, when I started my car up from cold, I immediately heard a loud tapping noise coming from the engine compartment. I turned the engine off and inspected the belts and fluid levels. Everything under the hood looked fine, so I started it up again. The tapping steadily declined in intensity for about 1 minute, then disappeared. I haven't heard it since.
It sounded a lot like misadjusted valves, but the intensity of the noise at start up was unlike anything I have ever experienced on other cars. What would cause this? Should I be worried?
Mika

 

Have you checked the oil?

 

Just had an oil change, and yes, I checked the oil level immediately... no problem there.
Any other thoughts?
Mika

 

Are you sure the place that changed the oil put the correct stuff in there? ie instead of 5W30 they dumped 20Wsomething. The only reason why I bring this up is because it happened to a friends honda civic. The dealership put the wrong oil in, and the car tapped until it was replaced with the right stuff...

 

I personally watched the oil change place open up quarts of Mobil 1 5w30 and dump them in, so I don't think that's the problem. Interesting observation, though.
Mika

 

miata's have the same problem. i think people were saying it's the valvetrain or something but it supposedly doesn't hurt anything. goes away in my car in under 4 seconds but a minute's a long time.