Engine Rattling on Cold Start (Timing chain tensioner?)

[dtopkin]

2015 SCV6 LR4 (74k miles) has a slight clicking/ticking noise when idling after cold start (videos included). Once the car warms up it's gone. No codes, and I suspect it's a timing chain tensioner, but thought I'd ask in the event that I can catch something early. I took the engine cover off so I could hear it more clearly, but when the engine cover is on, you basically can't hear anything.

Here's a link to the video/sound on cold start (It about goes away after a few minutes)

 

[f1racer328]

Any chance you can film a cold start?

 

[dtopkin]

Any chance you can film a cold start?

I included a link in the post to a video I recorded of it on youtube:

 

[dtopkin]

And then this is once it's idled for a few minutes, the noise is reduced quite a bit:

 

[dtopkin]

Any chance you can film a cold start?

I can try and get one of these a little later, yes.

 

[dtopkin]

Any chance you can film a cold start?

Here's that cold start video (apologies for the darkness, I was in the garage)

 

[Longtrail]

Sounds like a lot of tappet noise? I'm no expert; does the engine have hydraulic lash adjusters? I believe they're dependent on oil which may point to lack of oil or wrong oil? I'm happy for others to chime in as I'm just guessing!

 

[dtopkin]

Sounds like a lot of tappet noise? I'm no expert; does the engine have hydraulic lash adjusters? I believe they're dependent on oil which may point to lack of oil or wrong oil? I'm happy for others to chime in as I'm just guessing!

I've been changing the oil with the recommended spec from Liquimoly (+ ceretec etc.), every 5K miles. No leaks or issues on lack of oil. I've been religious about babying this beast. Been trying to diagnose this, especially as it's just on cold start. Only 74K miles on it, and because it's a 2015, I know the timing chain and tensioner guides were updated, but I do know that even then infrequent OCIs can lead to the tensioners wearing. My initial suspicion — if it is a case of the tensioners — is that the previous owner might've not had the OCI's as close as they should be.

 

[jlglr4]

I don’t really hear much out of the ordinary, and can’t tell much difference between the noise in the cold-start video vs the original video. Nothing sounds like a timing chain noise to my ears. That really light rattle that comes and goes a little bit (somewhat irregular) could possibly be the supercharger coupler, which are known to go bad and start rattling. You could take the SC belt off and see if that’s the sound you’re concerned about. I expect the loudest ticking noise I hear is probably the HP fuel pumps, which are known to be noisy (there was a TSB on fuel pump noise at one point). The other thing that can cause a ticking (if that‘s the kind of noise you are concerned about) is an exhaust manifold leak.

Have you owned the car long? Is it a new noise that you’re investigating?

 

[f1racer328]

Sounds pretty normal to me to be honest. The fuel injectors/pumps get a little louder as the vehicles age. I think someone on the forum here replaced their injectors and said their engine was quieter after.