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

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Originally Posted By: 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?

Not coolant leak, but vacuum leak. As there is no coolant in the intake as you know
 
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Originally Posted By: dhellman12
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.



As for the sodium and universal averages, it's good to be below the UA, but to really feel confident, you'd have to know the sodium level in your oil's virgin condition, and know the std dev for that element in the UOA. Overall, I'd say sodium isn't worthy of fret unless it does not drop over successive UOAs.

As for the silicon, it too should drop. Air filters are the most "free" with passing particulate in the first portion of their lifecycle. I believe that Jim Allen had information that stated 90% of all dirt passed through a traditional air filter happens in the first 10% of the lifecycle, IIRC (I don't recall his source; if I'm wrong someone please correct me so that I can ammend my quote). Therefore, if you just installed the Wix dry filter, give it time. The filter will load up and become more efficient and succesive OCIs should flush out residual.

This UOA isn't something to panic over. It's cautionary in that it has given you things to take note of, and monitor. Give it time to see if these issues settle.
 
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found the quote from Jim regarding air filtration:

Quote:
... you CAN change your filter too often and harm your engine in the long term. Air filters have two efficiency ratings, initial and final. The filter gets more efficient as it loads up. According to an air filter specialist at Parker Filtration I interviewed, 90 percent of the amount of dirt that will pass thru a filter in it's operational life will do so in the first 10 percent of use. A good filter might start at 97-98 % efficiency but in a few thousand miles, will reach 99% plus. One or two percent doesn't seem like a big whoop until you consider two percent is a 50% decrease in the amount of junk getting into your engine. Parker has a great training slideshow that shows the actual amount of dirt in this situation... sitting in a pile.
 
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Great info dnewton, really appreciate it. Sounds like I should give the Wix a little bit more time and see if the numbers continue to improve for silicon (hopefully at a much faster pace). I went back and checked my records again, the K&N was in place for the first 1300 of this 10K mile OCI. So the Wix paper filter had just under 9K when this new oil fill started.

Blackstone recommended running it to 8K for the next sample, but I'm thinking of doing a test when the OLM is up... probably closer to 6K.
 
I've never been a fan of the oiled-element air filters.

Not that they cannot do a good job. I think there are some systems that can perform very well. But, the key to that level of performance is proper maintenance of the oiled element. And that is the problem; it's very hard to get the right amount of oil on there, and very hard to maintain that level, and difficult to know when to wash/oil it (without doing frequent UOAs). They are difficult to "get it right", no matter how simple it looks on TV or the 'net.
- apply too much oil and it will saturate, pass and end up on the MAF sensor, which can cause big problems with running
- apply too little oil and it won't catch the dirt it's supposed to catch, allowing slow destruction of the engine

Dry paper filters are very reliable, work well, install easily, and don't need any maintenance to be viable. Install, use, replace; it's that easy. The level of filtration efficiency (from reputable suppliers like Wix, Purolator, Fram, etc) is good and repeatable. It gets "better" as it ages. Kind of hard to beat the ease/cost/reliable performance of a paper air filter.

Any filter typically gets "better" as it loads up. But why add the difficulty of oiling a cloth filter when it's not necessary? I do understand that there can be a fiscal savings by using a "reusable" filter, but to me the down side outweighs the upside, in this type situation. As much as I've seen great success with lubricant bypass filters (proven very reliable and effective), I question the viability of reuseable air filters (efficiency determined by the skill and knowledge of the person who maintains it, and it's VERY easy to get it wrong in both directions).

Food for thought.
 
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Originally Posted By: dhellman12
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





SILICON 38 46 38 33 30





With GM's 5.3 engines, I have come to the conclusion that there is something inside the engine made with silicone that comes off with use. It could be a silicon-bronze or silicon-aluminum metal inside the engine. It could also be a silicon gasket/seal wearing. I do not know, but like you I have also looked over the entire air system, and have not found any leaks. The smog air pump could blow silicone into the exhaust, but that is outside the combustion chamber and shouldn't end up in you oil. I have not used a vacuum gauge to check the vacuum inside the crankcase, but if it was high then dirty air might get sucked in through a seal or dipstick tube.
 
Let the filter load up, some short OCIs and check out all the air intake components for leaks/holes etc., another UOA
 
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