What the heck?? Uuuuggghhhh
 

Took the wife's 4.6 this morning for a short drive and I barely get two miles away on the highway and I get a low oil pressure message shut off engine message on the dash. What the heck? I had just got on a bridge with no shoulder and in the far left lane, took me a mile to get over off the bridge and get it shut down. By that time the timing chain(assuming) on the pass side was making a god awful noise. We had done a bore scope inspection of the guides, everything looked good and no pieces were showing up in the filter changes. Guess I am going to have to jump off and starting tearing this thing apart; wife is less than pleased. Is it normal for them to just let go all the sudden?

How many miles on your X5. You know its very common on the X5 V8 4.6is and 4.4 that after 100K its just a matter of time. Chain stretch probably occurred. Just replace the guides, chains, and tensioners and your good to go. One thing that concerns me though is that you got a low oil pressure condition. That seems strange for the guides and timing chain.

With no oil pressure you most likely burnt a rod bearing(s). I did rod bearing(s) on my first lotus with the engine in the car. You will need to drop the pan and remove each rod bearing cap to replace the bearing. If you burnt a main bearing you can also replace them with the engine in the car. There's a trick that my dad taught me with using a screw with the head grounded down to push the bearing out from the block.

Just remember a "Happy Wife means a Happy Life". Life is probably not good at the moment.

I'm thinking about popping off the upper timing covers and the lower pan this week to see what can be seen. If its just a timing issue then fix and move on and if there is any other damage then pull the motor as I hate working under cars.

With the pan off replacing the bearings shouldn't take more then a couple of hours. I would rather be on my back for a couple of hours then spending a couple of days taking the engine out and putting it back in.

Here's a link on how to remove the main bearing journal with the engine still in the car and without having to remove the crank. In instead of a bent cotter pin, my dad taught me to get a screw and grind down the head until it can push the bearing out without the head hitting the block.

https://www.youtube.com/watch?v=J6rk1azOOx0