Did I kill my Explorer???

[pet575]

Last night I was pulling my little fishing boat home. About 1/2 way through a 50 minute drive, my Low Oil Pressure warning came on in my message center, the needle gauge bottomed out, and the Hi Temp Low Oil light came on. Then it corrected itself within a few seconds, then it returned. Rinse, repeat numerous times. I suspected a cranky oil pressure sensor so I continued on until I could stop and check the oil. Checked it and confirmed it was filled to proper level. This issue had come and gone over the course of the last 2 months or so and this was only about the 4th time it had happened.

Continued on the final leg of the drive figuring I'd just get it home and figure it out from there. When I was about 10 minutes from my house running at about 70 MPH I noticed a power loss and then the engine made a REALLY LOUD rattle and then quit-all within about 5 seconds. CEL came on. Coasted to the side of the highway with the boat in tow and let it sit.

Efforts to get it restarted were fruitless. It wouldn't even turn over. Got it towed to repair shop and they are going to look at it this morning and pull the codes to tell me WTF is going on.

260K on the 4.6L and I'm wondering if it is toast. Had noticed it running more loudly over the last couple of weeks. A rattle/tick/whatever you want to call it at idle.

What do the internet shadetree experts like myself say?

Did the timing chain break? If so, is the 4.6L a model which will require me to replace the heads due to it breaking while running?

Did I lock it up because the oil pressure gauge was right? Did the oil pump fail intermittently to cause the warning I was getting?

I'm curious as to what everyone's thoughts are without the codes. The fact that it wouldn't turn over at all tells me it ain't something simple. I might have killed my vehicle. :-(

 

[BobRob]

Hard to say exactly what happened from your description, but the end result sounds like your engine is lunched.

That said, you never know and maybe you'll get lucky.

 

[2000StreetRod]

just guessing

The reported DTCs may not be helpful. If the starter will not rotate the crankshaft (crankshaft locked) it will be difficult to determine the cause without disassembling the engine. Intermittent oil pressure loss on the "gauge" coupled with a noisy engine indicates a good possibility of low oil pressure. The engine could be seized due to lack of oil pressure. I don't know for certain but I suspect the 4.6L 2 valve is an interference engine. Most overhead cam engines with fairly high compression are. The mileage on your engine is great enough that a timing chain guide could have failed causing the noisy engine. Pieces could have intermittently blocked an oil passage or the oil pickup causing oil pressure loss. Or one of the timing chains may have slipped causing the pistons to strike the valves.

If I were diagnosing the problem without the DTCs I would:
1. Carefully use a breaker bar/socket on the harmonic balancer retaining bolt to see if the crankshaft will move at all in either direction.
2. Remove the spark plugs and use an inspection scope to check for piston or valve damage.
3. Remove the oil pan and check for plastic and metal fragments from the cassettes and metal particles from the crankshaft and rod bearings. Also look for a bent connecting rod preventing crankshaft rotation.
4. Remove the valve covers and check for damage.
5. Remove the front cover and check for timing chain cassette damage.
6. Remove the rod bearing caps and check for destroyed bearings.

In my opinion the 4.6L has a tendency to spin rod bearings.

But bad rod bearings shouldn't prevent the crankshaft from rotating.

 

[pet575]

Well I got my diagnosis, er, death sentence.

Engine is locked up. Mechanic couldn't get crankshaft to move at all. Pulled off front cover and timing chain guides were almost completely broken off and gone. Mechanic agreed that it is likely that the fragments of the guide blocked oil pressure.

Thanks guys.

 

[XtremeRanger]

Hence the reason I went ahead and replaced mine when my dad owned it before I bought it. Prolly had 130k on it. still intact but replaced anyway. A friend of a freind had a rattle in his 02 a few years back, i pulled front cover and the guides were in 6 pieces.

 

[96firephoenix]

But bad rod bearings shouldn't prevent the crankshaft from rotating.

depends how bad. my brother managed to weld the bearings to the crank on my parents' dodge 5.9...