Lately my petrol engine (2.4L V6, Audi A6 C6 '05) started to sound more like a diesel engine. It feels like, whenever I give the tiniest amount of gas, there is some knocking noise. However, let's say I revved it all the way up to 7000 RPM and don't press the gas, it doesn't make the noise anymore.
So, whenever I actually give it gas, it makes the noise. I just can't hear it when it's idle..
I've done a bit of research and it seems that the 'Timing chain tensioner' could cause something like this?
How far am I off? I still drive it to work everyday and I don't notice anything in terms of temperature, mileage or anything..
It seems that after 4-5KRPM it seems to fade away, but that could be because of the engine noise being louder than the knocking...
Edit 1: Added recording from the inside, cold engine
Here's a recording when the engine was still somewhat cold, from inside the vehicle. It's fairly hard to hear..- but really focus near the end of a rev when the engine sound goes down a bit, the "trrrrrr" is still a bit audible.
I think you can hear it near the end of the recording, when I give it some gas and release a couple of times.. (0:42 - 1:05) https://vocaroo.com/i/s0UvkNFNYtwU (Sorry for my keychain, I didn't notice till later)
(Yes I know you shouldn't rev too much when it's still cold..)
Edit 2: When did this start?
I had hit the 'guardrail' on the highway with a speed of ~40KM/h (25MPH) with only the left side. This caused some slight damage to the radiator. The plastic covers on the side cracked which caused coolant to leak.
I drove the car roughly a quarter mile to a safe place and left it there. This may have caused some overheating but I doubt it.
After roughly 3-4 days after replacing the radiator and other damaged exterior parts, this 'ticking / knocking' has started.
I must note that there is one foam piece I couldn't fit correctly in between the front fender and the frame. The ticking could be a loose part hitting some other metal, as the engine is shaking.. but it's a tiny chance...
Edit #3: Added recording