Q: When staring the car and when it is idling, it makes the loudest rattling sound. The sound is not like a rod knock but more like something is loose.

asked by on February 02, 2017

OK so I m a single 43 year old mother of 3 teenagers,(say no more,right):). I'm no mechanic but I know my way around a car somewhat. Mostly from watching. That being said, you should definitely know, I HAVE a very KEEN SENSE OF HEARING...The 1st thing I thought when I heard it was.. Exhaust/Muffler. The 'shop' said it wasn't. OK whatever. It wasn't my car at the time so I really didn't care that much. Then my son(17) comes home an says "my friends are saying it's the motor and it threw a rod". Um OK..??. So I googled "Why does my Hundayi rattle when idling and starting it up". And I read a couple other people's inquiries about the same exact thing as what I am experiencing. So that lead me to you. "ASK A MECHANIC" so here I am, asking you for your opinion/input.
Honestly, I thought it was either the tranny or motor mount or some thing just ain't sittin in there right, ain't tightened down all the way..? I've checked all the fluids. Transmission fluid was only thing low.

My car has 180000 miles.
My car has an automatic transmission.

Noise from engine or exhaust Inspection $79.99 - $89.99 Get a Quote

Hi there. The noise could be a heat shield that is loose on your engine causing the loud vibration noise and it will appear to be a rattling noise. If the rattling noise is more choppy and not fast and changes when the engine is revved up, then there could be a rod knocking in the engine. But if the noise is choppy and does not change as the engine is revved up, then there could be a loose bracket under the engine. If you need further assistance with your engine noise, then seek out a professional, such as one from Your Mechanic, to help you.

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