Hi, Scotty.
I had just bought a 2015 Dodge Challenger, it has 85,000 miles on a 5.7l Hemi and 8-speed automatic transmission. I took it in for a presale inspection last week and they said the car had nothing wrong with it, so I bought it. The car sat in my garage over the weekend. Monday I start it up to go to work and the car made a rattle-grind noise for a few seconds at idle, it kinda sounds like a bag of empty soda cans being shook. It doesn't seem to do it once the engine warms up. It doesn't make the sound if I start it again once it's warm either. Some people say it's normal for a hemi to make noise at cold start, but I'm wondering if the timing chain or chain tentioner might be going bad.
I would like to keep the car, but the dealer does offer a 30-day exchange policy where I can trade it for an equal value of the purchase price.
Does it sound like the infamous Hemi lifter tick? Those engines are prone to camshaft and lifter problems ($$$$ to repair). If lucky it might be due to an exhaust manifold leak but you'd want be certain.
I don't think it's the tick, but I'll try to get a recording tomorrow. Currently on a business trip, so I probably get it around 5-8pm est
I tried to get a recording, but it didn't make the sound this time after sitting for 58 hours.
Got a recording of it this morning, you can hear it after I accelerate.
Hard to say but it sounds like it might a loose universal joint. I'd have a good mechanic look at the car to get a hands-on opinion.
Sometimes it makes the sound when the engine turns on while the car is in park, and the sound would increase if I press the throttle. Unless I'm mistaken, doesn't the universal joints only turn while the car is in motion?
I am going to take the car back to the dealer I bought it from and have them look at it tomorrow; I'll have to leave it with them for a few days to cool if they can't get it to make the sound when I get there.
If it was loose enough engine vibration might cause some noise. However anything suggested from here is going to be guess work, finding the cause of that noise is going to require a hands-on approach.
Fair enough, I am going to see if the shop can firgure it out. Thanks for the help
Turns out it was a loose flange on the catalytic converter, they tightened it up and so far the sound is gone
That would do it. Thanks for letting us know.
Doesn't sound like a tick. I'll see if I can get a recording of it tomorrow