1999 Ram Van B2500 with 318 cid (5.2L) 12 passenger / non-conversion
134,000 miles

Parked Sunday afternoon after return from church, but Monday after noon when cranked it makes a gosh-awful-loud knocking noise right near the front of the odd-numbered (driver side) bank.

I've always had a P0303 code (Cylinder 3 misfire) that did not seem connected to plugs or injectors so I just lived with it.

I've never had anything like this happen, but it sure sounds like a valve has come loose and is slapping around -- or (heaven forbid) a loose rod.

Any one know of some techniques to investigate -- I'm thinking of:
* Stethiscope
* Remove a sparkplug and look/listen
* Remove the valve cover to see if something's disconnected.
* Finally head-removal

Any other ideas??

Thank you.
Lee

 

I'd start with a compression test. I don't think you dropped a valve unless it happened to knock a hole in the top of the piston as well. With a valve floating around inside the cylinder there isn't enough clearance between the head and piston for the engine to turn.

Any chance the spark plug simply blew out of it's hole?

 

Ok -- I was thinking the valve stem was long enough that it would not come all the way out, but would just pop back and forth.

Will do some more checking.

 

Bent Rod -- yikes -- how could that be -- seriously we just parked Sunday afternoon and then Monday it's making the loud noise.

Sheesh. Oh well, glad to find it.

 

Sounds to me like a lifter is stuck. Do an oil change with high mileage oil.

 

This will most definitely straighten out that bend rod.

 

Wow, you really got that engine open fast!!

So can you just replace the rod, or is it that simple??

Just curious.

 

Two months is fast?
Yes he can replace just the rod (and it's bearing.)

 

We were wanting to get something smaller for "every day" use anyway, so we got a minivan and I allowed myself some more time, so yeah it's been 2 months.

Found a matching rod on e-bay. Might get it going this weekend. Vrroom Vrroom

Thanks.