V-6 Rod knock?

Hey all, I have an 08 with 6k miles on it. I started it last night and a god awful knocking erupted, like a rod was going to launch out. Oil pressure light wasnt on and it ran for about 10-15 seconds and i shut it down. I fired it up again and the knock was less than the 1st time and lessening as a few more seconds went by but i shut it down again. This morning i started it and it was hardly noticeable, warmed it up and it was back to normal.

Anyone have this strange issue before?....

 

I haven't ever heard of that before. I would take it to the dealer, you may not be able to replicate it while there, but they will at least have it on record so if your engine blows up it will be easier for you to make them replace it.

 

Drove it 2 days before this happened...ran perfect. Not like it was sitting for any long period of time.

 

I was just trying to describe the sound using the rod thing. I thought maybe it lost oil pressure for some reason like a bypass valve stuck open...just kinda scratchin my head on this one. I will fire it up again in the morning and see wat happens.

 

Tucson. Unfortunately I dont have anything to record it with. Seriously it sounded like it had no oil pressure, like it hadnt been started in awhile and the was no lubrication anywhere in the motor.

 

Any chance something got put in your gas??

 

No sir. Always In the garage. Ran great 2 days before this....

 

You wont get a huge knock with no oil pressure, unless the engine has already spun a rod bearing...

Oil pump failed on my 2.5L sentra. I started it and had it on for a few seconds with the oil light ON Of course after I noticed the oil light NOT going away, I shut the car off immediately and replaced the oil pump... It sounded fine even with no oil pressure....

 

I used "rod knock" as to describe the sound, thats how loud it was. I dont think it was as it started knocking as soon as it fired but ran perfect 2 days before hand...go figure...

 

You won't get good answer without a sound clip even then to actually get an answer over a message board which tells you exactly what is wrong is slim.

For me to try to diagnose this, I would have to hear this sound and drive the truck, as well as any mechanic would while trying to pinpoint the problem.

 

I realize that. I'm just looking to see if anyone has had a sinilar issue with this engine. I was a mechanic at a dealer ship about 20 years ago so i'm familiar with engine diagnosis, but now a days with all the new fangled wiz bang gizmos on cars I thought i'd see if anyone here had any suggestions. thanks for your help.

 

Could it just be piston slap?

 

Better not be w/only 6k miles!

No, it was loud as hell like something wanted out..lol

 

was it much colder outside then usual when this happened? an aluminum block will make what you may think of as a rod knock when it is cold, common complaint we hear at the dealership i work at in NY durring the winter

 

i say take it to the dealer and let them deal with it while its under warrenty. Belive me if it was rod knock it would be loud and the sounds wont go away.

 

Nope...about 75 degrees out. It ran fine just 2 days before... not a valve train noise,loud enough to scare the s**t out of me!

 

It was loud enough that i thought any second something was going to come out the side of the block. I'm fire it up tomorrow and see how it sounds.