Tapping/knocking sound immediately after oil change. Rod knock, piston slap, valve train ticking, or else?

[TumblrDucks]

This is very embarrassing. I have ran Valvoline’s new 5w-30 oil for 3k miles and changed it with same oil but 0w-20. As soon as I start my car I know something is wrong. There is a tapping/knocking noise from the back of engine.
This is what my engine used to sound:
Good engine sound
Here’s what I have now:
Bad engine sound

So far I have ran 300 more miles with this noise. This slight “knock” can be heard regardless engine is cold or hot; however sometime it will decide to go away and come back tomorrow. The engine didn’t consume oil or have other symptoms. Hyundai’s updated knocking sensor should catch rod knock but so far it’s none. What could be the problem?
I’m going to get some 40 weight High Mileage oil try to quiet it down. Guess I have to be a thickie for the theta2 from now on lol.

Thanks.

 

[TumblrDucks]

Anyone?

 

[carviewsonic]

Could be a coincidence, the change in grade shouldn’t make that much difference in engine sound. Worst case scenario would be Hyundai rod knock. Maybe should have dealer tech have a listen.

 

[oldhp]

Pour a qt of ATF in it and let idle for 30-45 minutes. Let drain at least 1hour. Put 5W30 in of your choice. I'll bet noise is gone.

 

[TumblrDucks]

OK did more test…
Disable injector 1-4 one at a time: no change, the “knock” still there.
Move throttle to various rpm: no change, no matter it’s 3k or idle I can still hear it.
Reset engine adaptation: no effect

 

[Four Rings]

Did you change the oil filter when changing the oil?

If yes, the filter itself could be defective and restricting flow. Try swapping out the filter for another one (change brand and use a premium grade filter) and see if the noise stops.

 

[TumblrDucks]

I also took my oil cap off and take a peek at the head. Shinning aluminum and amber color oil. One cam lobe that partially visible is nice, smooth and no scotch marks. It would be a crying shame is rod bearing decide to go now. Maybe two cold starts the car did when I try moving it on a ramp is the last straw for the Theta 2? Sigh…

 

[TumblrDucks]

Did you change the oil filter when changing the oil?

If yes, the filter itself could be defective and restricting flow. Try swapping out the filter for another one (change brand and use a premium grade filter) and see if the noise stops.

Thanks for the suggestion. Yes I do. Brand new OEM 35505 filter.
The only problem is I bought it from Amazon. They sell 6 packs for 30 bucks. Before all filters have genuine laser sticker on them. This time it is not. I hope the seller not bait and switch fake filters after gaining some tractions on sell…

 

[cptbarkey]

A video with it revving would be helpful. It sounds like vibrating metal or plastic somewhere externally.

 

[wwillson]

The bad engine sound is more like the fan blades hitting a hose or something that got moved during the oil change.

 

[Furious]

Swap out the filter, do not run it anymore until that is done.

 

[Lubener]

I heard the noise faintly on your "good" recording too. Try running a heavier oil.

 

[Cujet]

I am going to assume the noise is a real internal engine noise and not something external.

I'd pick a quality 5W-40 synthetic and a quality non restrictive oil filter (maybe like an M1 or K+N) and see what happens to the noise. It sure sounds like parts with excess clearance.

I've mentioned this many times, but ultra thin oil introduces a problem many are unaware of, it can escape anywhere there is excess clearance and starve distant components of pressure/flow. The Ford 5.4L 3 valve V8 is an example of this, where the oil pump backing plate leaks, and the plastic cam chain tensioners leak. Even in fairly new engines, the phasers and aft cam bearings can be starved for oil, resulting in real problems for otherwise intact components. Those that understood the problem switched to 10W-40 and the engines/phasers last 300K or more miles.

 

[i6pwr]

@TumblrDucks

What vehicle is this? Year/Make/Model?

What oil does it call for? Water under the bridge, but if it ran fine before the change, and made noise right after, why did you drive it?

A 20 WT oil should not (I believe it should not).. cause noise like this immediately.

It sounds like every rod has a slight knock, with OE bearing clearance, or every valve lifter/lash adjuster.

Are you sure it's 0W-20?

With a noise like that, it sounds like it doesn't have oil but no way you could drive 300 miles like that

Any oil pressure warming lights when going around turns?

This is definitely an odd scenario.

 

[Propflux01]

Doesn't sound like a rod knock. Especially since it is all the time and not just of decel. Since you changed two things on this, start there first. One is the filter. Replace it first. Two, the oil. 0w-20. It does not go with Theta 2.4L which calls for a 5w-30 oil. Check that filter closely, they like to clone those for some reason. When you bought them, did they have plastic covering the open part of the filter? If not, probably counterfeit.

While technically expired, probably due to the complimentary part, here is the TSB on oil for this engine:
https://static.nhtsa.gov/odi/tsbs/2019/MC-10163868-9999.pdf

 

[i6pwr]

0w-20. It does not go with Theta 2.4L which calls for a 5w-30 oil

Yeah, I would definitely get the correct oil in there first with a new filter.....fingers crossed.

 

[twX]

If you noticed the noise immediately on starting the engine and before the oil was up to temperature, the oil grade is not the issue. 0W-20 is much thicker than necessary before it's warmed up.

Change the filter, and cut the old one open if you can to see if it was defective. A filter that's too restrictive will cause a drop in oil pressure, but it won't be enough to trip the oil pressure light.

 

[Warstud]

Go back to using 5w30 and see if it's quiet again . My Truck recommends 5w20 but it seems to run smoother on 5w30 .

 

[JustN89]

The knock sensor is not perfectly able to identify rod knock. It looks for a frequency, and as an example, early iterations of the software confused rod knock with the pulses from the HPFP putting the engine in Reduced Power mode only to find out that the engine was fine upon inspection. In fact, as of 2022 and TSB 22-01-33H, the knock sensor update isn’t even on the diagnostic flowchart anymore as a requirement before engine replacement approval.

Put the correct spec oil in (reference the tsb posted by @Propflux01), with a genuine filter, and then if the noise still exists, it’s time to visit a dealer.

 

[TumblrDucks]

I am going to assume the noise is a real internal engine noise and not something external.

I'd pick a quality 5W-40 synthetic and a quality non restrictive oil filter (maybe like an M1 or K+N) and see what happens to the noise. It sure sounds like parts with excess clearance.

I've mentioned this many times, but ultra thin oil introduces a problem many are unaware of, it can escape anywhere there is excess clearance and starve distant components of pressure/flow. The Ford 5.4L 3 valve V8 is an example of this, where the oil pump backing plate leaks, and the plastic cam chain tensioners leak. Even in fairly new engines, the phasers and aft cam bearings can be starved for oil, resulting in real problems for otherwise intact components. Those that understood the problem switched to 10W-40 and the engines/phasers last 300K or more miles.

Thank you Cujet. Any particular brand of 5w40 would you recommend?