Valves? Tapping Cold Engine 2007 Altima 2.5

Not normal unless you've been stretching the oil changes or don't have the right viscosity in there for the temperature or have a cheap oil filter that doesn't have a working anti-drainback valve.

Not the oil.

Took it to a Nissan dealer and they did a repair on the catalytic converter which is covered under the Nissan Service Bulletin NTB08-001. However, that did not do the job. My further research indicates the problem may be related to that mentioned in service bulletin NTB08-014 which is outlined below.

I'll take it back to the dealer again and have him look at this as a possibilty. I have created a .wav sound of the noise so I can let him listen to what the actual problem sounds like when the engine is cold.

You can do a Google search on "altima ntb08-014" to see more about this as a possible solution.

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Description: 2007 NISSAN ALTIMA; QR25 ENGINE RATTLE NOISE WHEN COLD Rattling or knocking noise from the engine when all of the following conditions are met:

1. The rattle noise is not coming from the catalytic converter heat shield (refer to campaign bulletin NTB08-001), and
2. The engine oil level is in the operating range, and
3. Engine is OFF for 2 hours or more (cold soak of 2 hours or more), and
4. Cold start with engine coolant temperature below 122°F (50°C), and
5. The noise lasts for 1 minute or more during engine warm up, and
6. At idle or low speeds?engine rpm below 2200.

Here is what the noise sonds like:

Thanks for the feedback. Since you first posted, my daughter has complained of something similar on her '08 2.5. Keep us posted on how it turns out.

As I listen to that clip, it sounds like the loose timing chain noises that the 2.4 engine had in the Altimas 10 years ago. I hope that's not coming back.