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Discussion Starter #1
Truck now has 55,000 miles on it.
I've been using Amsoil synthetic 15/40 for over 30,000 miles with no problems, changing the oil and filters at about 10k intervals. I run slightly extended oil change intervals based on UOA testing (by Blackstone) at 5k mile intervals, usually at least once between oil changes to check for problems/wear.
A couple weeks ago I changed the oil at 9k miles and pulled an oil sample for UOA. Blackstone's report shows copper at 305ppm, which is 100x greater than it's ever been.
Does anyone have experience with what this might mean in terms of parts wear or other concerns? I can't think of any work on the engine that would've created this effect and the only brass fitting I know of in contact with crankcase oil is a quick-drain valve I installed 30k miles ago. It has a teflon seal so I can't imagine it's the cause of the copper hits. Any ideas?
Thanks.
 

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My kit came with a little breakdown of what each element meant.


But there is some guys on here that are smart on oil analysis.
 

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Bump for you because I'm curious as well.
 

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Discussion Starter #4
copper from oil cooler leaching?

I've read elsewhere that it's not uncommon for copper from the oil cooler tubing or fins to occasionally leach into solution and show up in UOA.
Since I'm at it, here's what was posted on another forum:

CATERPILLAR-HIGH COPPER
Per Caterpillar, high levels of copper found in oil analysis are a result of engine cooler core “leaching”. The zinc additive in diesel motor oils reacts with the copper cooler core tubes at high oil temperatures. This chemical reaction results in copper oxidation products forming on the surface of the tubes and then coming off into the oil as it washes over and around the tubes. Heat is a catalyst to this chemical reaction- the higher the oil temperature the greater the rate of oxidation and the longer the reaction process is sustained. This does not cause any damage to the cooler core, or to the engine. However, you will see the copper reading elevate to over 100 PPM. Copper is not a particulate in this case but is in solution in the oil. The PPM will start relatively low and increase over 100 PPM and stay at high levels for several intervals, and then return to normal. During the oxidation process, a hard film forms on the tube surfaces exhibiting the appearance of clear varnish. Changes in operating temperatures, and /or changing oil brands can chemically disrupt this film and begin the oxidative leaching processes again. This can occur in any system with a cooler core: Diesel or gasoline engines, Transmissions or Hydraulic systems.
SOURCE: Stavely Fluid Analysis, courtesy of Caterpillar Inc.
 

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Wow, good information...thanks for posting that. Sounds like it's just something to keep an eye on rather than worry about.
 

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I think it was just a mistake by the lab or a bad sample. If it was from the oil cooler you would of seen it in the other samples. Check the next one a little early or drop this oil early if your worried about it to flush out the system. This is one reason I wait until I get my UOA to change the oil. Then I could resample or flush the system with a cheap oil.
 

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Discussion Starter #7
copper still high - what about lead and tin?

Here's a follow-up after 7k more miles:
I normally run the AMSOIL at about 10k mile intervals with 5k UOA and a filter change at that time. My 2006 Duramax currently has 61k miles. Prior to 54k, the copper averaged 3ppm with lead at about 2ppm and tin at 0-1ppm. During the past 2 UOA intervals dating to my original post, copper went high (305-411 ppm) but lead (2-7ppm) and tin (0ppm) have remained low and in range with prior measurements so I'm inclined to think this is consistent with what's been reported about the oil cooler lines leaching copper and not likely to be bearing wear. However, does anyone see concerns with the lead's slight increase or other issues not already discussed in this thread?
Thanks.
 

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Here's a follow-up after 7k more miles:
I normally run the AMSOIL at about 10k mile intervals with 5k UOA and a filter change at that time. My 2006 Duramax currently has 61k miles. Prior to 54k, the copper averaged 3ppm with lead at about 2ppm and tin at 0-1ppm. During the past 2 UOA intervals dating to my original post, copper went high (305-411 ppm) but lead (2-7ppm) and tin (0ppm) have remained low and in range with prior measurements so I'm inclined to think this is consistent with what's been reported about the oil cooler lines leaching copper and not likely to be bearing wear. However, does anyone see concerns with the lead's slight increase or other issues not already discussed in this thread?
Thanks.
In your information from Blackstone what was their comment about the lead? Typically if it is out of normal ranges, they will identify it for monitoring. AMSOIL states 15ppm is in the normal range, anything above that is flagged for monitoring.
 

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Correct me if I am wrong but arent most of the lines ont these trucks aluminum?
 
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