High copper from oil cooler harmful?

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Jun 10, 2002
Does high copper from an oil cooler indicate a need to change oil? Just got my first run of Red Line back and copper was in the 40's. Everything else was exceptional. Now I am 99.9% sure it IS from the oil cooler because I got the oil temps much higher than my last run, causing the cooler stat to open much more often. And this was through summer. last analysis was winter. I don't think it is harmful, but want to make sure. How does it get in the oil? And in what form? I assume it's not particulate if it's not harmful. Why does copper do that? And do different types of oil increase that effect?
Copper "leaches" into the oil from the copper tubes. Being a soft metal, I don't think it does any harm.
Jason, The oil cooler on my Audi 100 does the same thing ...I typically see copper in the 50 ppm range after 12,000 miles on the oil. As long as it's not bearing wear, you are fine. What are the lead and tin levels? These are the alloying elements used in bearings .... TS
I think what is happening is this. A lot of copper dust and fine copper chips are left over from the machining and forming process. During approx. the first 30,000 miles, this contaminant is slowly removed by the filter and oil. As the copper forms a thin oxide layer on the inside, the copper oxide then prevents much leaching after that. If you don't have an oil cooler, Terry Dyson has a theory that on certain GM vehicles, its the front thrust bearings that are wearing.
Tooslick: Lead was 8, Tin not tested, actual copper was 45. I think I will also post the full report...My last analysis (in winter) had lead of 3, Tin 0, and copper 13. Molakule: my car is an '89 BMW with 163k miles so I hope nothing is left over from machining [Smile] Jay: Thanks...I saw that but I have not heard that before and if it is true I am curious to how/why.
Jason watch the trend of the copper levels. Actually copper leaching in small levels acts as a solid lubricant. I disagree that it is harmful for a oil, it will actually act as an antioxidant. The key is the source; what happened here is the strong esters in Redline cleaning up wear-in metals residue that weren't cleaned off by the other oils used over all those miles. Redline gets a bad rap many times incorrectly because it cleans microscopic levels of "plated" metals regular oils can't clean or remove. We had the same effect using vegetable only motor oils that are really strong esters and would unload a tremendous amount of "soft" metals that adhered to oil galleries etc. ppm is pretty small stuff.
I read on Lubrizol's website that there are additives in oil that mitigate the catalytic effect of metals on an oil's oxidation rate. "Organic complexes containing nitrogen or sulfur, amines, sulfides and phosphites form inactive film on metal surfaces by complexing with metallic ions."
I've heard that copper promotes oxidation in gasoline. If it can oxidize gas it probably can do something to oil too. The gas is only at normal temps, whereas the oil is at higher temps and for long periods. The higher temps accelerate chemical reactions. The normal antioxidants and other things in oil may offer some protection.
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