TheTallOne17
TheTallOne17 New Reader
7/1/21 7:38 p.m.

I've inherited a 2007 Silverado 1500 with 222300 miles on it, to become the work truck/tow pig

 

It unfortunately has traces of metal in the oil, but no codes, and runs (ran) strong. So far I've pulled the intake, heads, lifters and valves to go hunting for the cause of the metal shavings (there were a few in the filter when I cut it open), with not a ton of luck. Lifters appear in good condition, though the right bank was varnish free while the left bank had plenty to go around

One of the exhaust valves on the left bank (rear most valve) seems to have not been running as hot and is the same color as the intake valve, not matching the other exhaust valves

 

I have a 4 day weekend ahead of me, so what would GRM do? Drop the oil pan and check the crank? Open up the lifter valley and peak inside? Yank the whole engine and tear it apart?

Happy to add more pics on request so we can go on this adventure together

californiamilleghia
californiamilleghia SuperDork
7/1/21 7:56 p.m.

What kind of metal in the filter ?

magnetic ?

main/rod bearing chunks or  worn off particles of bearings  ?

has the motor been apart before ?

Ranger50
Ranger50 MegaDork
7/1/21 7:58 p.m.

It's probably the cam bearings. Do not replace. Run it until it dies.

TheTallOne17
TheTallOne17 New Reader
7/1/21 8:05 p.m.
Ranger50 said:

It's probably the cam bearings. Do not replace. Run it until it dies.

It's only job now is home depot runs and 1k miles at a time drive to races. If if was just Home Depot I'd do that, but towing a car long distances it concerns me. Why not replace cam bearings?

TheTallOne17
TheTallOne17 New Reader
7/1/21 8:06 p.m.
californiamilleghia said:

What kind of metal in the filter ?

magnetic ?

main/rod bearing chunks or  worn off particles of bearings  ?

has the motor been apart before ?

Seems to be magnetic, so steel. I havent checked bearings yet. They are definitely small particles (less than a grain of sand, the carbon in the filter was bigger), though I have found a couple small 3/4mm hair like shavings

Motor has never been apart

Ranger50
Ranger50 MegaDork
7/1/21 8:11 p.m.
TheTallOne17 said:
Ranger50 said:

It's probably the cam bearings. Do not replace. Run it until it dies.

It's only job now is home depot runs and 1k miles at a time drive to races. If if was just Home Depot I'd do that, but towing a car long distances it concerns me. Why not replace cam bearings?

You have oil pressure right?

TheTallOne17
TheTallOne17 New Reader
7/1/21 8:28 p.m.

In reply to Ranger50 :

Yes

Mr_Asa
Mr_Asa UberDork
7/1/21 8:35 p.m.

Absolutely sure the motor has never been apart?  Only one thing I can think of that would make the internals of one side look so much cleaner than the other.

TheTallOne17
TheTallOne17 New Reader
7/1/21 8:36 p.m.
Mr_Asa said:

Absolutely sure the motor has never been apart?  Only one thing I can think of that would make the internals of one side look so much cleaner than the other.

Yep, owned by my dad since 400ish miles, he's positive

 

I'm wondering if it could be a sticking intake valve that could cause that

dean1484
dean1484 MegaDork
7/1/21 9:58 p.m.

So you found a little bit of metal and tore the motor apart?  If oil pressure was good I would change the oil and run it a bit then take another look at the filter. A compression test and a leak down test would have also been on the to do list before tearing it apart.  A pothole or a set of RR tracks could have Jared a bit of casting slag loose and there was nothing really wrong with the motor. 

Look at the rocker trunnions for bearing issues. Also delete the AFM properly when you reassemble. Choose a good cam. Be happy. 

TheTallOne17
TheTallOne17 New Reader
7/2/21 7:09 a.m.
dean1484 said:

So you found a little bit of metal and tore the motor apart?  If oil pressure was good I would change the oil and run it a bit then take another look at the filter. A compression test and a leak down test would have also been on the to do list before tearing it apart.  A pothole or a set of RR tracks could have Jared a bit of casting slag loose and there was nothing really wrong with the motor. 

Its had metal in it thru 3 oil changes

TheTallOne17
TheTallOne17 New Reader
7/2/21 7:09 a.m.
Cousin_Eddie (Forum Supporter) said:

Look at the rocker trunnions for bearing issues. Also delete the AFM properly when you reassemble. Choose a good cam. Be happy. 

Looking into afm delete

TheTallOne17
TheTallOne17 New Reader
7/2/21 8:57 a.m.

An updated report from my dad: When the problem showed up 7k miles ago it looked like a tube of glitter had been poured into the oil, so much more than traces of metal

JBinMD
JBinMD New Reader
7/2/21 9:24 a.m.
TheTallOne17 said:

An updated report from my dad: When the problem showed up 7k miles ago it looked like a tube of glitter had been poured into the oil, so much more than traces of metal

Based on that new info I would definitely yank the motor our and take off the oil pan and valley cover to investigate further.  

TheTallOne17
TheTallOne17 New Reader
7/2/21 4:04 p.m.
JBinMD said:
TheTallOne17 said:

An updated report from my dad: When the problem showed up 7k miles ago it looked like a tube of glitter had been poured into the oil, so much more than traces of metal

Based on that new info I would definitely yank the motor our and take off the oil pan and valley cover to investigate further.  

Decided to go the yank motor route. There's so much caked on oil it at the very least needs all new seals around the crank

Patrick (Forum Supporter)
Patrick (Forum Supporter) MegaDork
7/2/21 7:58 p.m.

We had an 07 5.3 where something in the afm failed and turned the oil glittery, when it had just a hint of rod knock it came out and had 6 spun rod bearings.  

mjrj (Forum Supporter)
mjrj (Forum Supporter) Reader
7/3/21 12:00 a.m.

Per GM TAC minimum oil pressure in the 5.3 AFM engine is 27.5 psi, hot, idle, in drive.  If it doesn't make that, there's a problem.  Most of the time it was cam bearings.  Lots of camshaft and roller lifter failures.

When I went into fleet work, the company owned several GMC Yukon Hybrids.  They ran 24/7 and began to set low oil pressure codes.  No metal in the oil.  No clogged VLOM screen under the oil pressure sensor.  No budget for engine replacement and could not replace the vehicle at the time.  We ended up swapping from ac delco PF48E to PF63E oil filters and running 15w40 diesel oil, and checking oil level every week.  We had one that was assigned to a guy who could break a cannonball.  He finally broke one after 250+k miles.  I pulled it apart and found no metal in it and found the cam bearings good.  Ended up replacing the cam and lifters and he drove the wheels off it until the company's contract ended.  He ended up purchasing the vehicle from the company and as far as I know he still owns it.

dean1484
dean1484 MegaDork
7/3/21 12:51 a.m.
TheTallOne17 said:
dean1484 said:

So you found a little bit of metal and tore the motor apart?  If oil pressure was good I would change the oil and run it a bit then take another look at the filter. A compression test and a leak down test would have also been on the to do list before tearing it apart.  A pothole or a set of RR tracks could have Jared a bit of casting slag loose and there was nothing really wrong with the motor. 

Its had metal in it thru 3 oil changes

That would have been nice to know. 

TheTallOne17
TheTallOne17 New Reader
7/13/21 7:07 a.m.

The engine is now torn down fully and at the machine shop for fresh cylinder bores, a valve job, polished crank, and cam bearings.

I couldn't find any catastrophic damage, but with 222k on it and the engine already out it made sense to remove and refresh everything. Going back together it's getting an afm delete and a summit truck/towing cam unless y'all have a better recommendation for a reasonably priced towing cam

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