2004 pathfinder goes out with a loud bang

[jroo]

I am pretty sure my Pathfinder gave up the ghost tonight. I was at 145K and running very well. I picked my son up from school and went to grab something to eat before his basketball practice. Came back and restarted the truck and heard a super loud ticking sound. It sounded like all the valves started ticking but not the normal valve tick, I mean super loud clacking sound. A few seconds later, blue smoke pouring out the exhaust. It was too dark tonight to see anything so I will deal with it in the morning, but pretty sure motor is gone. Any ideas what would cause a sudden death of a decent running motor? It did use oil, but I was pretty good at keeping topped off with Fresh oil. I did an oil change about a week ago using the same K & N oil filter and mobile one syn I have used since about 40k. I did a quick check of oil and level seemed fine and oil is still clean looking from the recent oil change.

[atraudes]

The last time I heard a loud valve chatter like that the oil pump had gone out. If it was just one set of valves I'd say maybe a thrown valve or swallowed butterfly valve or something. Did any lights come on, and were any lights on before the failure? Did you turn it off or did it die by itself? How long was it running? The engine may be okay if you didn't run it too long.

Checking to see what codes got thrown would be your best first step since it doesn't involve cranking the engine. If the oil pump has indeed given up the ghost you absolutely don't want to run it at all. Unfortunately the only way to check the oil pump without tearing it down would be to hook up an oil pressure gauge and turn it over

[jroo]

I cut the engine off, it was running. It was coming from the top end like valves just way louder. Almost like a banging sound. The blue smoke came on the second time I tried to start the engine. I only ran it briefly, but you could hear it having issues running on the second start up. I didnt have any dash lights pop up when it occured.

[Buzzman]

Power valve screws fell out and got ingested into the engine.
Check the sticky at the top of this forum. The answers are there.
I think your engine is toast.
Keep us posted.

[jroo]

after reading the sticky at top, Im afraid that might be the cause. I am about 99.999 percent sure the engine is gone, but wanted to know why especially since I am pretty good about maintanence. Either way, it sucks. Coupled with mileage and the fact that my truck drank premium fuel like a drunk sailor I will be in the market for a car. Not worth investing in an engine

[atraudes]

It's pretty easy to confirm if it was a butterfly problem. Pull off the throttle body and take a look in the intake manifold. You'll be able to see a few of them that way. If you do and everything still looks fine, pull the top portion of the intake manifold (there's a step-by-step in the threadlocker howto). That should only take half an hour or so to do, minus setup.