Hey my Volvo v40 T4 2003 started making pinging sounds on cold start and while warming up if I rev it
It follows rpm
Before it started I noticed my plugs were white with a little deposit on them all 4. Ran great and still runs good making about 1 bar boost.
This sound freaks me out a bit
Video of sound below
https://m.youtube.com/shorts/LFnqRYLFph0?si=u-aUnf4vCUBro-fJ&cbrd=1
I would remove the drive belt and start the vehicle to see if the noise goes away… Let us know the outcome…
If you are unable to do something as basic as that, then you just need to take it to a pro mechanic shop for proper diagnostics…
Do you have a CEL light on?? if so what are the codes??
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No one will be able to tell anything from that very short little video clip.
“Pinging” is often used to refer to “detonation” or “spark knock” and is generally pre-ignition - as in the air/fuel mix combusts before it’s supposed to.
But it’s not something that happens on a cold start. It’s typically a thing that happens under load (like when climbing a hill).
It often sounds a bit like rattling marbles around in a metal can. I have no idea why it ever came to be called “pinging.”
In any case, skip the word “pinging” and be more descriptive. And tell people more about the car. How many miles are on it? And how old are those plugs that you checked out? What’s the maintenance history been like? And, like Dave asked, have you scanned it for codes?
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The car has 350k km
New Timing belt
Aux belt was off and there was still that noise
No fault codes present
Changed plugs and new ones turned white too so I guess either it’s getting mad hot or it’s running lean somehow. O2 sensor is going between 0.1-0.9 volt so it seems like it’s working.
This engine noise is unlike anything I’ve heard before
Based on everything you posted, I’d guess you are hearing piston rattle. Worn bores and worn pistons increase the clearance which causes the pistons to rattle in the bore until it warms up a bit.
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+1
It’s also referred to as piston slap.
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Could be lifter tap also. Pushrod motors have lifters. Some ohc motors have lifter buckets. Could be a oil related crud issue affecting lifter pump up.
Dohc, vvt. I think it has cam buckets? Not cam finger followers. Not a Volvo expert.
Detonation happens when the mixture is too lean, regardless of the type of gasoline, or if the timing is too far advanced for the grade of gasoline used. In both cases, it happens under at least some load.
A detonation sensor can retard the timing to somewhat compensate for a mixture that is too lean.
But actual detonation or pinging is not consistent. It will happen under some load and more so at certain RPM. Some other mechanical noise will be more consistent, and usually not require any load.
I’m just a knucklehead diy’er, no experience w/Volvos or turbos, but when the spark plug gap gets too large, my Corolla will ping, esp on long , steep uphills. My diy’er remedy is to replace the spark plugs. So far has always worked. Remember though , I’m not a pro mechanic, just knucklehead diy’er.
Knock sensor… 
Yeah i guess its some valve noise or something then or lifter
Exhaust cam has VVT engine knocks on idle after warming up i think its a bad vvt sprocket
Could explain my other issues but i dont really know
car is DOHC non hydralic lifter. I suspect a worn head.
Pistons slap when cold starting a little bit but not unusual for an aluminium engine with that mileage. Compression test reveals 140-150 psi
Doesn’t sound like piston slap to me. The pitch is far too high, the frequency too low, and the frequency slows and disappears at about 2 seconds. Hard to say, but if that’s as bad as it gets, I wouldn’t lose any sleep over it. I would suspect something as it relates to the timing belt replacement. You way want to make sure the engine mount bolts are fully tightened as I believe that needs to be removed where is goes through the timing cover when replacing the belt.
Anti-knock sensor, or really anti-detonation sensor!
Like an anti-sway bar? Not a sway bar?
Anti-roll bar, sway bar and stabilizer bar = all the same…
And knock sensor(s) use the ping/knock/preignition to adjust the ignition timing, the correct ignition timing is what stops the pinging, the knock sensor only measures the ping/knock/preignition and sends that info to the computer, then with other sensors and parameters the ECM adjust the ignition timing which controls the preignition… That is why it is best to run the octane recommended for the vehicle…
Nope it tells the ecm to retard the timing
Nope again, it senses the knock, when it happens. That is its only function.
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Could be the beginning of a head gasket leak or exhaust manifold leak.