I tried to not post a new thread, but didn't see the exact symptoms I have when searching the forum. Any help is appreciated.

Subject vehicle 2003 Tahoe 2WD 5.3 Flex Fuel 225k miles

About a week ago I drove 3-4 hrs with an empty trailer, picked up a Cavalier and drove home. About 30 minutes from the house, the Tahoe stalled pulling up to a light. It didn't want to restart, but finally did, and had a VERY pronounced tap, like a lifter or valve. I pulled off and checked the oil, and made the "brave" decision to baby it home. About 10 minutes later, I pulled off again to discuss the situation on the phone, and no tap..... Haven't heard the tap again until this afternoon. Truck has been parked since yesterday. My wife heard it tapping when backing out of the drive way so she stopped to check the oil. It didn't want to start again, and has a very loud tap. Seems to be left cylinder bank, under the valve cover.

Any ideas?

 

The hard starting could be due to low /poor compression , but could also be due to low fuel pressure...
What I didn't see in your original message was if you had to add oil each time you checked it?

You could try pulling the valve cover off, start the engine and see if you can identify the offending lifter, it will be messy so be careful of doing it on a hot engine.

 

The first time, no, oil level was fine. Second time, I added 1 qt. The rear main is leaking like crazy. The first time it acted up, once it ran, it ran great. Took 2-3 attempts and feathering the throttle to get it started. Keep in mind, I was towing a car and pulled like a champ, so I feel safe ruling out compression. Fuel, very possibly, but it would have to be an intermittent issue as well. That's what has me stumped, is how the tap and the hard start are related. After some research, I'm betting the tap is indeed a lifter (gonna try a flush and maybe pull the valve cover). But what about a tap could cause a hard start??? Also, right now it will start fine, but still has a tap.

 

AANNDDDD significant metal on the drain plug.

 

Sounds to me like you have a major engine failure. metal is no good and if you had or have valve taping noise my bet is you have a cam lobe wiped clean

 

The minor problem you may have is the oil pump failing, and if so, it is going to compromise the engine soon.

 

Read a few posts about that, and that's my best guess. I have one sliver that is nearly 1/4" long and about 1/32" wide, and a couple of other "larger" slivers, all pretty shiny. Then there is maybe half a pencil eraser worth of small dirty "filings". Guess its time for a new family hauler. The Explorer Sport is NICE! - Wife wants something a bit smaller

Thought about that, and the gauge, in true GM instrument fashion, has stopped working. But as far as I know the the low pressure light, and low pressure and low level message center still work, and nothing indicates low pressure there. Also, the problem seems very localized to the left front cylinder bank. One push rod (third from front) had a slighty irregular wear on the ball against the rocker. So, although I can't rule it out at this time, I feel like I have a lobe going on the cam, or a stuck lifter. Additionally I've read about the oil pump o-ring leaking and aerating the oil, so the lifter doesn't function properly.

Either way, the motor ultimately needs a tear down. 2003, 221k miles, hail damage, torn driver seat, and in need of tires.....
I think she's done her time. - Maybe a Sante Fe. They have a great warranty.