Potential Timing Chain rattle noise?

[Loki Motorsports]

Hey all! I have been hearing a sound lately coming from what sounds to be the driver side of the engine bay when cruising. The sound is most pronounced while cruising around town, generally in the 1600-2800 rpm range. It happens under light or heavy throttle, and is intermittent at what RPM it chooses to make noise at. Sometimes it's 1800, sometimes it will do it both at 1800, then be fine until 2800 or so. It does ultimately taper off after 3K RPM until redline, nothing to be heard there. It's a metallic sound, and sounds identical to if I were to smack a timing chain up against the valve cover, or something of that nature. Another note for diagnosis, it seems to only happen when the engine is at or close to OT. First thing in the morning when the motor is cold, it does not make this sound.

Car has 105,xxx miles. All stock aside from ACM mod.

Thanks ahead of time!

[Loki Motorsports]

Minor bump... Anyone got any ideas on this one?

[R3dliner]

Are you sure it's not pinging(sounds like marbles in a tin can)?

[Loki Motorsports]

Originally Posted by R3dliner

Are you sure it's not pinging(sounds like marbles in a tin can)?

Thanks for the reply... And no it doesn't sound like pre-detonation. It doesn't seem to be engine load dependent either, however, it IS temp sensitive. If I had to describe the noise... It sounds like tapping a screwdriver on the inside of a cast metal case of sorts. Difficult to describe. It really sounds like a timing chain rattle. But I wanted to ask the rest of you guys to see if this is a common noise.

[dparm]

The valvetrain is notoriously noisy. It could just be that.

Based on the fact that it is not engine load dependent, and that it doesn't get louder/faster as engine speed increases, I doubt it's the timing chain.

[Loki Motorsports]

Originally Posted by dparm

The valvetrain is notoriously noisy. It could just be that.

Based on the fact that it is not engine load dependent, and that it doesn't get louder/faster as engine speed increases, I doubt it's the timing chain.

Would the valvetrain only make audible noise at certain RPM ranges though?

[amrazM]

Does it sound like a light tapping? Mine started doing that after going down weight in oil.

[dparm]

Originally Posted by Loki Motorsports

Would the valvetrain only make audible noise at certain RPM ranges though?

I don't know. The valvetrain is obviously moving faster at higher RPM, but other sounds start coming into play that can mask things. This is why auditory diagnosis is notoriously difficult.

One of the first things I would do for an undiagnosed noise in the engine bay is to get the car on a lift and visually inspect for anything obviously loose, bent, or out of place. Sometimes it's stupid stuff like a piece of debris wrapped around a hose, or a heat shield that has loosened up from shitty roads.

[Loki Motorsports]

Originally Posted by amrazM

Does it sound like a light tapping? Mine started doing that after going down weight in oil.

Negative. I run Red-Line 10W-60, with a pretty quiet valvetrain.

[Loki Motorsports]

Originally Posted by dparm

I don't know. The valvetrain is obviously moving faster at higher RPM, but other sounds start coming into play that can mask things. This is why auditory diagnosis is notoriously difficult.

One of the first things I would do for an undiagnosed noise in the engine bay is to get the car on a lift and visually inspect for anything obviously loose, bent, or out of place. Sometimes it's stupid stuff like a piece of debris wrapped around a hose, or a heat shield that has loosened up from shitty roads.

I'll take this advice. Probably something that should be done soon anyways, I haven't done a full bolt check on the car in about 15K miles, it's time for another anyways! I will report back after this weekend with any findings. Thanks parm parm.

[kooolaid]

Any updates? I've been hearing metal chirping sound from my car for several years now. Took it to the dealer and inde and no mechanic could pin point the source. Mine is 6MT, and it first started on 3rd gear around 1800 ~ 2300 rpm but now I hear in all gears. It's more pronounced during hotter days, when engine is fully warmed up, and when engine oil is lower. I replaced my chain tensioners and it got little smaller but still there. So I ended up assuming it's stretched timing chain over time and load...

[asma123]

Are you sure it’s the engine making the sound? I’ve heard that heat shields can cause issues like these for our cars

https://www.m3post.com/forums/showthread.php?t=1872839