I've recently bought a Niro 4 Hybrid and am very pleased with it. Bu there's been one small problem - an annoying rattle or slight knocking or creaking noise generally triggered going round bends or over bumps. It was very difficult to identify where it was coming from, just somewhere behind the driver towards the back of the car.
Anyway, I found the cause - the tailgate. There are 2 black plastic guides either side of the tailgate opening, one fixed to the body, the other a mating piece on the tailgate itself (each side). I think what was happening was due to body flexure these locating pieces were slightly moving against each other, but because of stiction not smoothly, thus causing the noise. I've applied the merest wipe of vaseline to these parts and problem has gone! I expect it will return, but I know what to do next time.
Annoying Rattle
I had a similar problem coming from the rear near side. I have a 21 reg Niro 4, cannot find the black plastic guides that you have described.
I found about half way up on each side of the tail gate there is black round adjuster. When the tailgate was closed I pressed on the tailgate on the off side and there was no movement. When I pressed on the near side the tail gate there was a bit of up and down movement. I then unscrewed the adjuster and it moves out and mates up with a round bit of black plastic fitted to the body of the car. I adjusted it until there was no movement and that cured the problem.
I found about half way up on each side of the tail gate there is black round adjuster. When the tailgate was closed I pressed on the tailgate on the off side and there was no movement. When I pressed on the near side the tail gate there was a bit of up and down movement. I then unscrewed the adjuster and it moves out and mates up with a round bit of black plastic fitted to the body of the car. I adjusted it until there was no movement and that cured the problem.
2021 Niro 4 HEV Pearl White
