Help! Random rattle from engine
Thread Starter
Racer
Joined: May 2009
Posts: 470
Likes: 15
From: Corona CA
Help! Random rattle from engine
I've developed a random metallic rattling at the front of the engine. Been like that for a few days. It sounded like a loose bolt. Yesterday I got a chance to try to find it and it sounded like it was coming from the water pump. It sounds like a small piece a metal, like a bolt, where I hear nothing for a few seconds and then a some random rattles. It's almost like a bolt in a can sound. It isn't a heavy knock so it doesn't sound like it is the bottom end. I removed the drive belt and the sound didn't go away so it isn't the water pump.
The sound is there cold or hot. It doesn't have a rhythm to it and doesn't sound like valves.
I'll start digging into it this weekend but was wondering if anyone had any ideas or places to start.
Thanks.
The sound is there cold or hot. It doesn't have a rhythm to it and doesn't sound like valves.
I'll start digging into it this weekend but was wondering if anyone had any ideas or places to start.
Thanks.
Safety Car
Joined: May 2011
Posts: 3,807
Likes: 508
From: Oshawa, Ontario
I've developed a random metallic rattling at the front of the engine. Been like that for a few days. It sounded like a loose bolt. Yesterday I got a chance to try to find it and it sounded like it was coming from the water pump. It sounds like a small piece a metal, like a bolt, where I hear nothing for a few seconds and then a some random rattles. It's almost like a bolt in a can sound. It isn't a heavy knock so it doesn't sound like it is the bottom end. I removed the drive belt and the sound didn't go away so it isn't the water pump.
The sound is there cold or hot. It doesn't have a rhythm to it and doesn't sound like valves.
I'll start digging into it this weekend but was wondering if anyone had any ideas or places to start.
Thanks.
The sound is there cold or hot. It doesn't have a rhythm to it and doesn't sound like valves.
I'll start digging into it this weekend but was wondering if anyone had any ideas or places to start.
Thanks.
Melting Slicks
Joined: Dec 2013
Posts: 2,232
Likes: 315
From: Bridgewater New Jersey
There have been a few posts here about the loose camshaft bolts.
Before it does anymore damage, as I fear it can, you should investigate asap. If you wrench on your own car, I would suggest taking the cam senor out of the front engine cover and giving that a inspection. The cam senor will usually show wear/scrapping marks at the surface. You maybe be able to wiggly the cam a bit through the sensor hole to check the tightness.
GL
Thread Starter
Racer
Joined: May 2009
Posts: 470
Likes: 15
From: Corona CA
Thanks. The car is parked until I figure it out. I guess I'll need to drop the steering rack, remove the accessories, pull the balancer and pull the cover, right? Does the water pump need to come off or does the cover clear it?
Team Owner
Joined: Sep 2000
Posts: 25,001
Likes: 2,701
From: Far NW 'burbs of Chicago
St. Jude Donor '13
An experienced friend had this happen on his C6, turned out to be just some crummy gas that was causing mild knocking. Others have reported the same and say it may sound like a real mechanical problem.
Of course, could be something completely different...
Good luck.
Of course, could be something completely different...
Good luck.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
Safety Car
Joined: Jul 2009
Posts: 3,755
Likes: 190
From: Baton Rouge LA
St. Jude Donor '14, '16
If the cam bolts are loose the cam position sensor will be damaged most of the time and you can pull that fairly easily. I'd start there if you're sure it's not a belt tensioner or something.
Le Mans Master
Joined: Feb 2014
Posts: 5,463
Likes: 1,138
From: Chino CA
There have been a few photos on here of the harmonic balancer starting to separate and the front edge was right up against the steering rack. If that is happening, you can see it by looking down from the passenger side of the engine
Burning Brakes
Joined: Oct 2015
Posts: 1,139
Likes: 108
From: Arlington Texas
If you end up pulling the harmonic balancer I'd upgrade it to one made by ATI or similiar since that also a known problem with LS motors. It's kind of like a "while it's apart scenario" so you don't have to do it again later. Good luck.
Safety Car
Joined: Jul 2009
Posts: 3,755
Likes: 190
From: Baton Rouge LA
St. Jude Donor '14, '16
I think you could with the right extensions from underneath. Last one I tried to pull had swollen up and was hard to get out of the timing cover though so a little warning there.
Safety Car
Joined: Jul 2009
Posts: 3,755
Likes: 190
From: Baton Rouge LA
St. Jude Donor '14, '16
Thread Starter
Racer
Joined: May 2009
Posts: 470
Likes: 15
From: Corona CA
I checked and it isn't the ATI bolts but good idea. Here's a video of the sound. This is with no drive belt. It's the morse code noise.
https://www.youtube.com/watch?v=ssfa...ature=youtu.be
https://www.youtube.com/watch?v=ssfa...ature=youtu.be
Safety Car
Joined: Jul 2009
Posts: 3,755
Likes: 190
From: Baton Rouge LA
St. Jude Donor '14, '16
I checked and it isn't the ATI bolts but good idea. Here's a video of the sound. This is with no drive belt. It's the morse code noise.
https://www.youtube.com/watch?v=ssfa...ature=youtu.be
https://www.youtube.com/watch?v=ssfa...ature=youtu.be
Safety Car
Joined: Jul 2009
Posts: 3,755
Likes: 190
From: Baton Rouge LA
St. Jude Donor '14, '16
It's not quite as rhythmic as the one here but it really could be the cam bolts. I think you can get to the sensor so I'd definitely check.
https://www.corvetteforum.com/forums...ine-knock.html
https://www.corvetteforum.com/forums...ine-knock.html