If your symptoms are like mine, it's the valve train you are hearing when the engine is cold and before the oil has time to circulate and get to it. Mine has done this since I can't remember when no matter if the ambient temps are below 32F or above 100F when the engine is first cranked dead cold. I just had my RL in the shop last week for a warranty repair to replace a noisy timing belt idler (they also replaced the tensioner, timing belt, and water pump since the mechanic was already behind the covers), and I asked that very question. The mechanic said it was just normal valve train noise for this type of engine before it has time to warm up and the oil to circulate. I assume he meant because it is a VTEC with its unique valve train design. I should have asked if that was what he was implying, but I didn't.Very loud tapping noise coming from engine when cold.
Sounds like a tin can filled with marbles when shaken.
2008 ridgeline 5200 miles
Well, to make it more clear, mine is nothing like what you're describing evidently. I just found that the valve train is a little noisier on mine when the engine is stone cold compared to after the oil begins to circulate and get up into the valves good. It usually only takes maybe 30 seconds or less for the noise to dissipate, and I can actually hear the noise begin to subside as oil flow gets to the valves and begins to damp out the sound. I only mentioned the difference in a cold valve train sound compared to when it is warming up in my earlier post to suggest there is a difference that can be noticed. I just found the difference in the two sounds of mine to be a little more noticeable than I have on other engines I've been around (i.e., V-8s, even some 4 cylinder ones) that's all. This is why I mentioned that it may be due to the VTEC design as compared to other non-VTEC valve trains -- but I could be totally wrong (which is usually more common than not in my case). However, the sound with mine when cold is nothing to really mention compared to what you are evidently experiencing! Sorry, and I hope you get it resolved to your satisfaction ASAP!Will do, I will let you know the out come
The noise is so loud that my wife can hear it when I am down the block about 400 feet.