5.3 Metallic clanging

[GangstaCowboy]

Hello-
Just dropped my 2006 Tahoe off at the shop for a clanging noise come from the back of the engine by the transmission. Shop says it is something under the cylinder head, I think he said valve rollers? Common problem they say. Anyone had a similar problem? I have seen online about the rocker arm problem but it does not sound similar at all. They want to charge about 2-2.5 I think for the repair with a possibility there could be damage to the cam once they get in there. Should I take it for a second opinion? This shop has been repairing my cars for 2 years now and they have been up front and honest before. Sound is almost like a marble in a can going around, I thought it was the converter but no transmission problems or vibrations.

 

[Vette66]

Without actually hearing it or seeing the truck. My first guess would be toque converter bolt came loose and is rolling around the trans housing. If the engine and trans ran fine when the noise was going on it should not be a rocker.

 

[GangstaCowboy]

I thought it was the TC as well but the noise was faint at first and continues to get worse and worse every time the motor is started. I thought about towing it to the dealer to get a second opinion as it's definitely internal and not on the top of the engine where the lifters are. Would something in the valves cause a noise with out causing engine vibration or power loss?

 

[Vette66]

Generally if you mess with the valve train on any cylinder you will feel it in hesitation or a miss.

 

[livingez_123]

Maybe a broken flex plate or crank bolt.

 

[Vette66]

Before they pull the top end apart have them pull the inspection plate on the trans to see if there is obvious signs of any floating around in there.

 

[GangstaCowboy]

Shopped called and said its bad lifter and I should replace all 16 to the tune of 2k. Seems high. Plus there could be more surprises inside once they open the motor.

 

[GangstaCowboy]

Just to post some follow up info. The engine had a bad lifter. Had all 16 replaced for 2100. The shop showed me the bad lifter and it was pretty chewed up but they said there was no damage to the cam so that's was some good news. The other lifters looked fine but I went ahead and had all new ones put in. I tried some of the tricks from YouTube on trying to free up stuck lifters but mine was clearly a part failure and none of those methods reduced the noise.

 

[afpj]

Thx for the followup. I was confused when you mentioned noise by tranny. I assumed that meant down below, not up top. Was the noise clearly coming from the top of the motor?

 

[Sir Lapalot]

The marble in a can-sound!!! I have that also. Prev owner said he'd been to stealership after stealership and no one could figure it out (which I don't quite believe). I had the exhaust manifold bolts replaced (thinking one of them broke off and was rattling around somewhere) cuz that's what a shop said it was...but it wasn't.

For me, it happens when starting from a stop/at lower RPM's. As the RPM's get higher/more constant, then the sound either goes away or I just can't hear it over the road noise.

Great follow-up, thanks! (but wish it wasn't a $2100 fix :-S).
Someone else told me that it could be a bearing that's gone, and he said that if I took my oil pan off I should be able to see gouges in the oil pan from where the bearing was clanging into the oil pan. Haven't tried that yet, but I plan to next time the oil gets changed. I'm hoping it's that (and that it's a cheap fix, of course) but we all know how that goes.