No warning, how can this be?
I just wish we knew what was up.
Flexplate and flywheel are ok.
Yeah, these situations can stump ya.
Last edited by Paul Bell; Dec 26, 2013 at 08:10 PM.
Have someone check the intake bolts, see if they are loose..if they are and it rained just before all this happened its a safe bet you have internal engine damage. You will need a good mechanic to help you from here.
ALSO Is it possible you are hearing a brokem AIR check valve? That sits right over the valve cover. They can make a hell of a racket if the insides break off.
When we wash it, only a light shower spray is used.
Granted, we have only had this car since May, so we don't know the conditions that it was exposed to prior to us owning the car. The car originated from KY, and then we bought it from MS.
If, water did get into the manifold, wouldn't these sounds, or damage have happened way before us getting the car?
My husband did not look at the car yesterday, so we will have to wait on the replacing the valve cover with just placing it on and see if it makes that sound again.
The Best V8 Stories One Small Block at Time
Yes, if this happened before you got the vehicle, it would've damaged the engine at that time, well before you bought it.
Moving on...
The current theories are:
-Flexplate is cracked;
-Valvetrain is hitting something in the rocker cover;
-A.I.R. check valve.
Anything else people?
Valve cover was put back on by hand, not bolted down, and no clunking sound.
I guess next would be to remove the spark plugs.
Thank you all for your advice. Just going step by step trying to find out why it is making this sound.
I'm wondering what would happen when the valve cover is bolted back down in place?? hmmmmmmmm
Maybe the valve cover needs to sit differently? Heck, I don't know anymore. So aggravated by all of this.
I'm about to just sell this car and be done with it, and be at a major loss with it.
HUH, I'd also have a hard look at the harmonic balancer.
Let's confirm something: The banging sound ONLY happens when the valve cover is bolted down? Is this consistent? It ALWAYS bangs with the valve cover bolted down?
Valve cover on
http://s256.photobucket.com/user/tyl...b9b44.mp4.html
Valve cover off
http://s256.photobucket.com/user/tyl...4b023.mp4.html
This DOES not apply here, but it does give a good example of why checking the flexplate is a good idea.
About 10 years ago my dad and I were trying to get his 71 GMC K10 with a 350 drivable, and a friend said to adjust the valves. That did not change anything. Next he said it was a spun rod bearing, and the engine needed a rebuild. When I was just starting to pull the engine and removed the sheet metal clutch inspection cover. I noticed that the cover was bent at the spot by the crankshaft, I started the engine and the 'rod' knock was gone. The truck has ran 'knock free after that. The only thing need to fix it was bending that sheet metal cover back into shape and putting it back on.
The point of that is that it can be very hard to guess what a problem is even when standing next to the vehicle with the problem.
BUT there is no signs of chips, dents etc. on the valve cover.
Is the flex plate and flywheel two different things?
I saw the flywheel and that was good.
The shim for the starter was good too.






