Long story short, I hit a solid piece of concrete that used to be where a basketball goal was when parking in a friend of mine's front lawn yesterday and now the car has a weird knocking noise. I've read on here in the past to detect a spun rod bearing:

1. set the parking brake and start the car
2. rev up to the rpm's where you hear the "knock" (in my case, between 2500k and 3000k) and hold it at that rpm range
3. engage clutch, go into 1st and let out slowly until the car nearly stalls
4. if noise disappears, it's considered a spun rod bearing and if not, it's something else

Even when I drive it, the noise is only apparent when slowing down or downshifting. Well, the noise never disappeared after doing the test, but when i put the car on jack stands, the only noticeable thing is the underbar that's closest to the front of the car's right side bolt has the dust from where i hit the concrete. Everything else appears to be fine. Can it be a possible exhaust leak? I'm kind of new to this so any help would be greatly appreciated.

 

drop the oil see if you have any metal shavings i highly doubt you can spin a bearing from hitting something

 

where did it get hit? The oil pan?

 

Gonna have to, and i just changed that oil too lol thanks

C130flyer, that's what I thought I originally hit, but the oil pan's fine. Not a graze on it at all. Got lucky on that part. It's just one hell of an annoying sound.

 

lol... does the knock get faster as you rev up? does it sound like your motor has bb's bouncing in it? does it sound like its coming from the head? if not its not rod knock.. the only way you can cause rod knock from bottoming out your car is if you puncture the oil pan and drain all your fluid and drive with no oil.. probably something very stupid you broke.. be thankful its not a spun bearing they are not fun to replace and very expensive since you have to change everything oil hits.


explain how you hit the concrete piece and how far back did it hit? you might of damaged the drivetrain somehow.

 

Knock doesn't get faster at all. However at the rpm range described is the only time I hear it. Even when the car's sitting still. I ran straight over it at about maybe 7mph. But the only way you can tell I even hit it is by looking at the right bolt of the underbar that's closest to the oil filter because it's has concrete dust all over it. That's why I thought it was the oil pan.

 

get the car jacked and have someone rev it while you are under it so that you could hear where exactly it is coming from. i doubt is a spun bearing.

 

Now that i've gotten some sleep since I worked graveyard shift last night, after looking at it again, I noticed the underbar is touching the exhaust which is nearly dead on exactly where I hit that concrete. Possibility? Oil's fine. No shavings.

 

Sounds like the exhaust is just rattling on the underbar.

 

is it a tin noise or a blunt force noise? if you had rod knock it would sound HORRIBLE at ANY RPM. Dont ask me how I know

Sounds like you pushed the exhaust pipe up against the heat shield above it and now its making a horrible tin noise. Or you could have wacked the driveshaft depending on the angle and loosened something up. Either way its an easy fix so dont panic to much.

 

or this to ya. might have bent one of the underbars up and now its hitting the exhaust.

 

It's a tin noise. I think it's the underbar personally because it is bent up. Im trying to put a pic up now.

 

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First pic shows the general area. Second pic shows exactly where I hit the underbar.

 

unbolt the bar and see if it still does it.. if so its the shield around your cat.. that def looks like it would rattle.

 

You guys were right. No noise. And I didnt even take the bar completely off. Just the bolt that I hit. I noticed the bolt's snapped.