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White Pearl 2019 Hyundai Tucson SE FWD
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Discussion Starter · #1 · (Edited)
I've noticed an odd start-up sound happening every now and then with my Tucson, usually when the car has been sitting for at least 3 or so days. Once it warms up it seems to go away and is very quiet. If I start the engine again after it's been sitting for an hour or two I don't seem to hear this noise. As of now I have 21K miles. I'm currently using full synthetic 5W-30 oil and Top Tier premium fuel. When I changed the oil last November no metal shavings were present. I also have fuel diluting the engine oil but it's minor and I keep a close eye on it. I haven't had any other issues with the engine or car itself.

What could I be hearing? Knock? Piston slap? I've read plenty of horror stories of Elantra Nu's experiencing many problems and making similar noises. Any ideas? Has anyone else experienced this?

Thanks

***All 3 recordings were taken from the right front wheel well and the hood was closed. My phone was resting on the top of the tire. The first and third recordings were in a garage so there was a little echo.

 

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Doesn't sound like knock to me, more like the high pressure fuel pump metering more fuel to prime the cat converter. The HP fuel pumps are noisy and crap sounding best of times.
 

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Mine does the same thing.
It's either valvetrain or fuel pump.
Definitely not piston or rod knock.
I've heard those before; they are a deeper sound.
 

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White Pearl 2019 Hyundai Tucson SE FWD
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Discussion Starter · #5 · (Edited)
Mine does the same thing.
It's either valvetrain or fuel pump.
Definitely not piston or rod knock.
I've heard those before; they are a deeper sound.
I'm surprised to hear you experience the same thing. I guess that makes me feel a little better. I know what noisy direct injection sounds like (2 other cars in my family have it) and I also know what valvetrain noise sounds like (a previous vehicle was a Toyota Tacoma that had "Taco Tick" and was pronounced, but considered normal). What's weird about my Tucson is it only sometimes sounds this bad, especially if I haven't driven my car for several days.

Upon this start up, I thought it was just a dry start since oil had plenty of time to drain to the crankcase, but as the idle went down it sounded to me like a metallic knocking noise that's crankshaft-related. My first thought was slight piston slap or rod knock because the Nu engine is well known for this and other piston/crankshaft problems, especially in Elantras. I've read plenty of horror stories on it occurring as little as 50K miles. In another thread, someone commented their 2.0L 2018 Tucson experienced engine failure. It threw a rod. :/
 

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I'm surprised to hear you experience the same thing.
Mine makes similar sounds when cold, maybe not as loud as yours, can't tell from the recording.
It's not enough to notice with the hood down.
Again, I've heard engines with bottom end noises; this is not bottom end noise.
I could be from part of the VVT mechanism.
 

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White Pearl 2019 Hyundai Tucson SE FWD
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Discussion Starter · #7 ·
Mine makes similar sounds when cold, maybe not as loud as yours, can't tell from the recording.
It's not enough to notice with the hood down.
I should have mentioned this prior and in the video but all 3 recordings were taken from the right front wheel well and the hood was closed. My phone was resting on the top of the tire. The first and third recordings were in a garage so there was a little echo.
 

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2018 tucson 2.0 AWD, 1992 Volvo 940 turbo, 1998 Volvo S70T5m, 1996 Jeep Cherokee 4.0
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I've heard a lot of valve train and bottom end noise and that doesn't sound much like it. I'd also be inclined to go with something like the hi pressure pump making noise. If you want to confirm you can use the old mechanics trick of taking a long thick flathead screwdriver and putting the tip on the pump (or anywhere else you want to try to listen for noise) and then your ear on the other end of the screwdriver and have someone start it. Or you can go to harbor freight and buy a cheap mechanics stethoscope.
 

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Discussion Starter · #9 ·
Since posting this video here, whenever I start it, it sounds normal to me. IDK why it sounded weird that one day. I've now gotten in the habit of building up some oil pressure before starting by flicking the key 2 or 3 times. Doing this has several benefits, especially to the CVVT system. As for the metallic rattle-like noise when revving the engine, it can be heard just before 2,000 RPM. I don't think it necessarily goes away as the RPM increases, but it's not as noticeable. I don't think it's the direct injection. I'm specifically talking about a rattle that occurs at a certain RPM and is not simply injector ticking. I have 2 other vehicles with DI, so I know what that sounds like. I experimented with noise yesterday, and I can't pinpoint where it's coming from; my guess is somewhere behind the engine and right. I'm beginning to think it's not from the engine and is instead from some heat shield . . . This engine isn't very smooth so I wouldn't be surprised if something is loosening and beginning to rattle.
Whatever I'm hearing shouldn't be too serious. The car barely has 21K miles. It's too new. I'm not doing anything about it.
 
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