Tfreestyle

My roommate has a 04 Lincoln Aviator, 4.6L Dohc motor. Figured this might be a better place to ask the question since you guys are alot better at this then like an explorer forum.

140k miles- Timing chain was rattling on passenger side of motor, he brought it to a couple shops, they said needs a new timing chain with about a 3k price tag, ya right. He decides to do it himself with a friend. All done with the install, car starts up, idles perfect, sounds great, Start to drive it around the block and within 1/4 mile get low oil pressure light. Did it another time to make sure it wasnt just a fluke but came right back up. No codes or anything. Need advice on what this could be.

To add, when he removed the valve covers there was ALOT of sludge, havent seen that bad in awhile.

Any help would be greatly appreciated

MaxxRPM

How did the chain guides look? Any broken peices that could be clogging the screen?
I'd replace the oil pressure sensor (oil sending unit) if it's not too much of a pain or cost just to eliminate "that" possibility.......even though that's probably not it.

Other than the pickup tube screen being physically blocked, another possibility could be if you forgot to tighten the chain tensioner(s) to the head(s).