Loud rattle at start, after sitting for an hour +

[P1Racer]

As in the title, I'm hearing a loud rattle once I start my car after it's been sitting for more than an hour. It's very loud and it only lasts for about 1-2 seconds. I have a video that I'm uploading below.


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[mecg]

What year is the car, how many miles, when was the last oil change and what oil filter was used?

[P1Racer]

What year is the car, how many miles, when was the last oil change and what oil filter was used?

2005.5, 149k, oil change at 146k with liquid moly 5w-30. Using Mann filters only.
Side note: this has been happening for about two months now. Only recently became louder.

[mecg]

The maintenance schedule states that the timing belt be replaced at 110K miles. Was that done?

[P1Racer]

Yes it was, here is more maintenance that I've done since the .
Timing belt, timing belt roller, tensioner, drive belt, water pump, spark plugs and coils, turbo drain gaskets, leak detection pump, turbo coolant lines, oil housing assembly,


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[P1Racer]

The maintenance schedule states that the timing belt be replaced at 110K miles. Was that done?

Yes

[mecg]

Well, I've listened to your startup a lot of times and it sounds to me like it's probably just the oil draining back into the oil pan and the wear on your engine showing until oil pressure builds and gets to where it needs to be. I personally don't think it's bad for a motor with ~150K on the clock, especially where the noise stops quickly. The only suggestion I have for you would be to use 0W-40 or 5W-40 weight oil instead of the 30 weight you are using now. That will probably help.

[P1Racer]

Well, I've listened to your startup a lot of times and it sounds to me like it's probably just the oil draining back into the oil pan and the wear on your engine showing until oil pressure builds and gets to where it needs to be. I personally don't think it's bad for a motor with ~150K on the clock, especially where the noise stops quickly. The only suggestion I have for you would be to use 0W-40 or 5W-40 weight oil instead of the 30 weight you are using now. That will probably help.

Is it possible my oil pump chain is worn?

[P1Racer]

Well, I've listened to your startup a lot of times and it sounds to me like it's probably just the oil draining back into the oil pan and the wear on your engine showing until oil pressure builds and gets to where it needs to be. I personally don't think it's bad for a motor with ~150K on the clock, especially where the noise stops quickly. The only suggestion I have for you would be to use 0W-40 or 5W-40 weight oil instead of the 30 weight you are using now. That will probably help.

I have been able to prevent this from happening by priming the ignition once or twice before starting the car. Not sure if that helps to isolate what I can do to repair this?

[mecg]

Nothing from me, other than you saying that priming the oil before starting it prevents the rattle, which confirms what I said.

[P1Racer]

Noticed there is a small amount of oil leaking from the cam cover. Maybe it is my cam tensioner, etc