Tap, Tap, Tapping noise from the engine

[ranger7ltr]

I have been running a new engine in my Sport since last May and had no issues at all...Just over 15k miles...Until now...

This engine started this light tapping noise earlier this week that would briefly go away if I put the tranny in drive... But it would come back after 5-10 secs...

It sounded like a loose pulley or torque convertor rocking inside the flexplate or maybe even the rockers tapping...The problem is the noise was coming from the bottom end...

So I got under the truck this morning and found the heat shield from the rear cats resting on the exhaust pipe...Hmmm...Reset it and got it positioned correctly...Start the engine and the noise is there...

Ok...Use my sthethescope and found the noise at the drivers side exhaust manifold...But not as much on the passenger side manifold...Hmm...

Thinking that maybe the torque convertor nuts came loose[not likely] but pull the starter and rotate the engine to check each one...Tight as the day I installed them...Hmmm...Put the starter back in and start the engine...Tap, Tap, Tap...

While I was looking at the drivers side of the engine for what it could be, I touch the oil dipstick to check the oil while the engine is running and I FEEL THE TAPPING THROUGH THE HANDLE...

I pull the dipstick and the dipstick holder is hitting the crank inside the crankcase and thsi is causing this noise...When I loosen the nut to remove the nut that is holding it, the noise stopped..I saw the tube move about 1/8" and the noise STOPPED...

I tighten the nut back up and the tube moved as it got tighter and the noise comes back...So I pull the tube after pulling the exhaust manifold and I can see shiny contact marks on the bottom of the tube...So I was going to cut a 1/2" off of the tube but instead put a spacer on the bolt that holds the tube bracket and tighten the nut again...The tube moves a bit as it gets tight but no tapping noise this time...

I don't remember there being a spacer on the dipstick tube on the old engine but this one has one on there now...I was thinking this shortblock was coming apart until I felt the dipstick tube making contact inside the block...But even with a spacer on the bolt holding the tube it still seals to the block and seats into the hole in the block...

And I pulled the oil pan this morning as well to see what the tube was hitting...Looks like the tube was touching one of the crank throws and doesn't seem to have done any damage inside...And I don't see any metal off the bottom of the tube; just scratches and a little bent metal...I did open the old oil filter I removed Friday and see no metal in the pleats...

Has anyone else seen or run into this problem with the dipstick tube?

 

[Turdle]

yup
I had one do that-it was bent just a tad at the bottom. Bend it out of the way and it should be tick free.
I think I took one from one engine and stuck it in another when this occured. Had me going for a while until I touched the dipstick.

 

[MatthewP]

Sorry to bring up an old post. I think i am having the same issue. tapping only occurs in drive at low rpm's. Question i have is what exactly is tapping the dipstick or the tube bolt on the side of the block?

 

[tmwalsh]

This discussion is about a noise from a dipstick tube that had been moved from block to block, or possibly nudged while working on the engine. The tube inside the crankcase just needed to be moved out of the way of the rotating crankshaft throw, either the weights or the connecting rod journal.
The positioning of the dipstick is not critical except that it stay out of the way of the rotating bits. It must, however, be seated into its bore in the block or incorrect oil level readings will result. The arm welded to the tube that the retaining bolt penetrates might have gotten manipulated when removing the tube from the block, or during installation. Or the tube itself got bent trying to get it to move past the exhaust manifold, or when the engine was being hoisted out of the vehicle.