New to the forum and I need some help. Wifes 96 Grand Caravan was making a horrible banging noise from the back head. The towers where the rocker arm bar mounts had broken in the past. Thought that was the problem, pulled engine apart to get to rear head. The valve cover for the rear head has visible damage on the far left hand side (as looking from the front of engine), but no visible damage to the rocker arm itself. Ised a pry bar and attepted to move the rocker arm bar in every direction I could and nothing moves that should not move. I even checked the mounting bolts and they ar tight. I even cranked the engine over with valve cover on and now does not make any noise.

Suspect something was sitting on top of the rocker arm and beat on the valve cover but can not find anything Even pulled the entire intake manifold and nothing - no damage visible and nothing in valley. Going to drain oil and see if anythin gnow down in the oilpan. Question is, what could have gotten on top of the rocker arm to cause the damage to the valve cover.

Hate to sepnd big dollars on new gaskets and the time toput engine back together and have same problem. Has anyone heard of this problem?

 

Bump the ignition a couple times. Check the suspected rocker again. Should still feel snug. I would try it a couple times to make sure that it is good at multiple points in the engine revolution. As far as anything solid being in there you would see some evidence. Is there any build up? Could of been a piece of petrified sludge. Maybe something got caught in the valve seatand you heard the piston hit the valve.

 

We have cranked the engine over several times and inspected the rocker arm. All move normally, nothing seems out of the ordinary. There is no visible damage on the rocker arm itself, but there is visible damage on the valve cover. We have looked everywhere for anything that could have gotten into the valve train and caused the damage without finding anything. Pterified sludeg I would think would not cause the damage on the inside of the valve cover, but I have been wrong before. Right now I am just guessing. However, I dont want to spend the money to put all new gaskets on and have the same problem after I put it back together.



















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You can run the engine with the valve cover off. If you have strong oil pressure you can lay a strip of cardboard over the journals. This will give you a better chance at seeing or hearing if there are any issues. If nothing is out of the ordinary I would go ahead and button her up and drive.

 

As it stands right now, we have pulled the intake manifold (upper and lower) out to inspect into the lifter valley. I don't have the resources to drop the engine out of the vehicle to tear everything apart. I have removed everything needed to get to the rear head. We can still crank the engine over, but it will not fire. So we are only watching the rocker arms moving at cranking speed. I have tried to move the suspect rocker arm in every possible way, other than a little side to side movement, it is tight on the arm. I can not lift it off the push rod, I can not push the valve down with my hand. I have looked at the towers where the rod mounts and can not make it move in any direction. The bolts holding the rod down are tight (i understand they have a habit of stripping/breaking).

I am going to drain the oil and run it through a paint strainer to see if there is any metallic fragments or shavings in it. I am trying to check out everything before I button it back up. I am still puzzled on what could have caused the damage. I do not see anyway of anything getting in there to get on top of the rocker arm.This head was replaced over 2 years ago, so anything left in there by acident I would think would have done this a long time ago.

Prior to pulling everything apart, the engine started right up, there was no loss of power. However, the engine sounded like someone beatinging on the bottom of a tin can. When the problem first started, the oil light was flickering in sync with the banging noise. With the engine cold, the oil light does not come on. I have checked the oil level and other than it could use aoil change it was fine.

Sorry for the long post, I am on a tight budget and I cant aford to regasket the engine and have to pull everything back aprt again. Yet, I dont want to replace a head if I dont have to (that would put a real dent in the budget).

I want thank you for all your help in this matter,