Sorry if this is a dumb question. I'm not too familiar with my way around cars so forgive me if this is obvious.

I have a 2013 Acura TL (SH-AWD) with about 65k miles. For the past 6 months or so, I've been getting this weird sound (best way i can describe it is knocking) on startup. It didn't always happen, and when it did it would only last about 5-10 min. It normally disappears in the middle of my commute. So because of that, I could never get a mechanic to diagnose it properly because by the time I get to their shop, the sound is no longer there and I'm not able to explain to him clearly enough on what the problem is. I even arranged to leave my car there overnight on two separate occasions but since it doesn't always appear, they were not able to recreate the problem.

Fast forward 6 months later... the sound appears to be more frequent and seems to be getting louder. I took a video of it.

https://drive.google.com/open?id=1lT...f46-6rXS3FdEh6
(I just uploaded, so if it doesnt play through the web browser, that means google is still doing some post processing on it. You will either have to wait or just download it and play it locally.)

I did some googling and it sounds exactly like engine knocking (i am hoping I'm wrong on this).

Anyone have an idea what this is and how to get it fixed?

Also a note. I did take my car to Acura about a year ago to get the oil consumption issue checked out. I know I have oil consumption issues in this car, but they told me i am still "within spec" which I think is under 1L per 1000 miles. I do occasionally check and top off my oil, but I'm not going to claim something ridiculous as saying I check it every few weeks. It's probably more like every month or two. I'm not sure if this is a related problem.

 

I wouldn't say its knocking,
When I picked up my TL SH-AWD with 68k, it was making a much similar sound, granted not as loud.
I had some of the more experienced Technicians I work with mess around with it some and we all came to the same conclusion,
Now, this diagnosis is just from my experience, and from the audio you gave me.

I'd say that your TL has one or more lobes on the camshafts are scored and will need to be replaced.

Lucky for me I was in the last 2 weeks of my OE power train warranty so I quickly got it over to my nearest Acura dealer, who came to the same conclusion and replaced both camshafts.

The link below is to another forum post about this issue, you might find some more answers there. (It helped me greatly)
https://acurazine.com/forums/4g-tl-p...solved-972181/

 

Thank for that link. That does seem to be the same problem I have. This was a CPO and I purchased extended warranty. I'm just hoping Acura honors it like the guy in the other thread.

 

I'm almost positive it's not the cam lobes... I had a Pilot (has the same series engine, a J35) make that noise and it was something fairly cheap and easy to replace...when I get home I'll look at the invoice for it.

Can you remove the plastic covers and place your camera/phone closer to the back of the engine near the flywheel (if safe to do so) ? I remember it being most pronounced in that area and only for about 20-25 minutes during cold starts.

 

So I found the invoice, they replaced the belt tensioner (this is not the serpentine belt tensioner, this was the timing belt tensioner).

Here's a noise that sounded similar, but mine was much louder on my Pilot:

 

100% your timing belt tensioner. My '09 had the same noise. Had the timing belt, tensioner, water pump, spark plugs replaced and it completely solved the issue.