cloverfield

It was really nice in LA today, so I drove with the windows down to enjoy the soundtrack our cars make. I noticed when accelerating past 3k rpm, or during acceleration with a transmission kick-down, I'll hear two metallic 'tick' sounds coming from the engine. It feels like one from each side, right after the other, and then just normal engine acceleration noises.

I don't feel the timing is being pulled due to detonation, and the acceleration still feels linear. It's repeatable at each stop light or whenever the car's been stopped and that type of acceleration is needed.

I checked around the exhaust manifolds and didn't really see any signs of leaking, but I'll admit I don't really know what to look for. No check engine lights or any of that.

Any idea what it could be? Are there secondary intakes that open at certain rpms or throttle positions that could be producing this noise?

Thanks for any help!

Harold1898

Check your oil level ASAP

cloverfield

Oil level is totally fine...and temps are constant at about 216-220F.

Harold1898

Sorry I can't help you. There are some extremely knowledgeable blokes in here. One of them will guide you. All the best from down under.

cloverfield

I appreciate the response! This could be something totally normal, like the engine pivoting under load, or it could be something not so normal. I'll get to the bottom of it one way or another.

Harold1898

I have a 2012 C63 and it does not make any unusual noise when I accelerate. Mind you I often hear a very loud exhaust sound and some tyre noise followed by a traction control unit noise. Come to think of it, I hear that all the time!
Stay in good health.

cloverfield

Hah, that's generally what I hear too. Maybe it's my car revolting against the crappy California summer blend fuel we've switched over to in the past month. 91 octane is the highest we get, and I'll bet that's really not 91. Time to find some stations that sell racing fuel!

Harold1898

Certainly could be pinging if that is the case.

m a x i m u s

matt, are you out having fun with your car without me? lol. i have a ton of strange noises, but not the one you mention ...

NS_C63

What are the mods on the car? Or is it stock? Mileage?

m a x i m u s

Btw, I believe they sell "racing fuel" (higher than 91 octane) at the 76 on Pico and Bundy.

cloverfield

A buddy filled his CTS-V up with me at the Chevron on Westwood and Santa Monica Blvd and is experiencing pinging as well. So here's a good use case for our cars burning through a tank of fuel as quickly as they do Also, that Chevron has now been blacklisted forever!

The 76 @Pico has 100 octane gas for $10/gallon, but I wonder how fast the ECU adapts to it? To get to 93 average in the tank, I think we'd need about 4 gallons of it mixed with 91. I'm willing to give it a shot to see if it solves the ticking noise.

m a x i m u s

That's a good idea. How about dumping in a bottle of octane booster?

cloverfield

That's exactly what George recommended at G&N. Bought a bottle, pulled the battery, boom. No more pinging. Stay the hell away from that Chevron.

m a x i m u s

Did he mention anything about your knock sensor?

cloverfield

No, and of course I thought about that as I was driving away. I have an appt w/them tomorrow for brakes so I'll ask him then.

khaloof

My car used to make this sound also at start of acceleration,switched to Shell and Mobile,no more ticking sound.
Good Luck!

Asian

sorry for bringing this back. Does it sound like this? When cold only?

cloverfield

^To me that sounds like the footwell trim / cabin filter area is rattling a little, or it's something in the cowl near the HVAC intake/blower is loose and permeating through into the cabin.

Asian

So I’m guessing our sounds are different. it’s an external sound too if I drive in an alleyway you can hear the echo off the walls.
Anyway, this I believe this to be motor related since it only happens when cold, and it follows the revs at 1500-2000rpm goes away once 100F oil temp or so,
and adding oil to dipstick max level drastically improves this, but sound is faint still.
I’m guessing just normal lifter wear noise but I was wondering if anyone has had this properly diagnosed, and/or if some guru can just warn me that my car is about to blow up. Haha