04 Tahoe, 5.3L 141K, 10k Amsoil Signature 5w30

[TXHunter]

Switched from a K&N to a Wix paper filter to see if that was the source of Silicon, but doesn't appear to be the case (although #'s are slightly better). I've taken the entire air system off and put it back on twice and can't find anywhere that might be leaking.

Code:


OIL ASL5w30 ASL5w30 ASL5w30 ASL5w30 Unknown

MILES IN USE 10K 9K 7K 5K 3K

MILES 141K 131K 129K 127K 122K

SAMPLE TAKEN 9/3/12 11/13/11 9/13/11 7/30/11 4/25/11



ALUMINUM 4 3 3 3 3

CHROMIUM 1 1 0 0 1

IRON 18 16 11 12 19

COPPER 21 18 16 14 16

LEAD 48 16 10 7 14

TIN 5 0 1 2 0

MOLYBDENUM 140 149 130 146 18

NICKEL 1 1 0 0 1

MANGANESE 1 1 1 1 1

SILVER 0 0 0 0 0

TITANIUM 0 1 1 1 6

POTASSIUM 5 0 2 4 0

BORON 48 52 65 104 8

SILICON 38 46 38 33 30

SODIUM 26 67 61 57 212

CALCIUM 3252 3588 3270 3332 1694

MAGNESIUM 14 15 14 15 12

PHOSPHORUS 535 733 750 756 667

ZINC 616 840 932 958 806

BARIUM 0 0 0 0 0



SUS @ 210F 62.1 62.3 59.1 61.4 57.3

cSt @ 100C 10.82 10.86 9.96 10.62 9.45

Flashpoint 435 435 435 415 390

Fuel %
Antifreeze % ? ? 0.0 0.0 0.0

Water % 0.0 0.0 0.0 0.0 0.0

Insolubles % 0.2 0.3 0.3 0.2 0.4

TBN 1.9

 

[addyguy]

That silicon dirt ingestion is destroying your bearings, albeit slowly.

There is a chance it is 'residual' dirt in the engine...I'd try to 'flush' the engine out with some short 3k dino runs, and then re-start extended OCI's.

 

[tig1]

GM engines do show a lot of metals, but as we know that doesn't have a thing to do with engine life. By the way, I grew up in Arlington on West 4th st. in the 50s. Population was 7000 when we moved there in 49.

 

[Donald]

I think 10K is pushing it with that oil & engine. But its possible the silicon will take another oil change to come down. I am not a fan of the K & N type air filters. Amsoil sold them years ago.

Do you vacuum and wipe clean the air intake box which holds the filter. Sometimes you need to look at all angles for a leak. After some looking and thinking, I concluded that there should be a gasket between a TBI and a spacer. There was none. Went to the dealer and they had one listed so I got it.

 

[LargeCarManX2]

On my 3.5 Chevy engine, I found a plastic tube from the air cleaner to the intake manifold that had a hole in it. About half the tube was melted. So when the engine was running, all that dirty air was being pulled in from the hole in the tube. The tube was suppost to bring in filtered air. You might want to look in those areas of the manifold...should be two!

 

[oggb]

Gotta check vacuum lines as well as the intake plumbing.

 

[Brons2]

Lead jumped way up, that's not good. Dial back to 5K OCIs and see how it does.

 

[jkhawaii]

Don't think it has to do with the silicon, the silicon has been about the same on all the samples. Wait a minute! You went 10 months on this sample vs 2-3 for all the others, that would mean you have been doing more starts, stops and short drives. That would explain things.

 

[jkhawaii]

Intake gaskets do tend to leak on these engines, though it was the longer time between changes that likely caused the lead spike

 

[jjcom]

The upper intake on those engines is plastic and GM plastic manifolds can have a tendency to warp. I'd check all around on it to make sure you've got a good seal all the way around. The hose that bolts on the throttle body has a tendency to warp with age, I've seen those lose their roundness and leak even with a clamp. Also the plastic "muffler" thats right there can fall apart. I'd make sure to double check that.

Plus the issue with lower intake gaskets on GMs across the board. Might be a good idea to clean the whole motor off and monitor for leaks anywhere.

 

[buster]

May have a small coolant leak, hence the higher bearing wear. Oil held up well considering.

 

[Geoff]

PCV valve? They get sticky/plugged and create crankcase pressure issues which can suck more air in.

 

[Artem]

Originally Posted By: Brons2
Lead jumped way up, that's not good. Dial back to 5K OCIs and see how it does.


What would 5k OCIs show when comparing to the previous runs of 10k, 9k, 7k?

A spike in wear is normal as the engine doesn't always see IDENTICAL use from OC to OC.

As already mentioned, this run was about 10 months vs the previous runs of 2 months to rack up the same amount of miles. Of course wear is going to be higher due to more cold starts and completely different driving conditions.

 

[TXHunter]

The previous samples of 5,7,9k were the same run of oil. The wife did 9k in about 7 months on the first run, and 10k in about 10 months on this 2nd fill.

 

[SteveSRT8]

Originally Posted By: jkhawaii
Intake gaskets do tend to leak on these engines, though it was the longer time between changes that likely caused the lead spike


Did you notice the year of this vehicle?

 

[SteveSRT8]

Originally Posted By: Geoff
PCV valve? They get sticky/plugged and create crankcase pressure issues which can suck more air in.


Many of our 5.3's in Silverados have no pcv valve.

 

[ltslimjim]

This screams coolant or anti-freeze. No way should this engine have this much silicon and sodium readings on these oil changes.

 

[TXHunter]

Sodium is actually below the universal average for this engine type. I'm not sure this screams coolant/anti-freeze.

I am concerned about the silicon, K&N was in service for 1300 miles on this 10K mile oil change before it was switched to the Wix paper. It is trending down, but not as quickly as I expected.

 

[ltslimjim]

^Therefore, to be sure it's probably best to run some short 3,000 mile OCIs in order to flush out remnants, rinse and repeat then sample your next extended interval. If numbers are still high the problem is still present.

UAs take with a grain of salt. That's only based on the data they collect, how do I know the 5.3Ls tested have several coolant leaking contributors?

 

[mattd]

Does the truck use any coolant?