What's up guys, noticed a quick half second rattle today for the first time ever when I started up my G. I have 104k on it, did a full synthetic oil change probably 2k ago and the level is good on the dipstick. If I start it again immediately or while the engine is warm, there is zero noise. It has happened twice today, once in the morning after sitting for a couple days and once on the second cold start after I let it sit for 5 hours.

Here is a video, if you listen closely it is just for a brief moment right after the engine starts. It goes away immediately after and is not heard when driving. I have read stuff about timing chain noise or piston slap but I have never heard this before in my 6 years of ownership.

No engine codes, never have let the oil get low on the dipstick as I check religiously. Previous threads have said that the noise is common but I am not sure. Any ideas on this one? Thank you for the help, I know it is a quick noise but you should hopefully hear the quick rattle/grind. The only other thing I can think of is this was the hottest day of the year, felt like 101 outside. Maybe the 5w-30 was too thin for the heat?

 

Someone recently commented a good way to see if it's the timing chain tensioner or not. Pull the fuel pump relay, crank the engine over a few times to put oil pressure on the tensioner, then put the relay back in and start the car to see if it still makes that sound.

If it doesn't (and you can consistently get it to not make this sound with that process) then it's probably the timing chain tensioner.