La Bamba's Cummins powerplant finally got a looonnnnggg overdue oil change.
The wear metals look really low due to the large amount of make-up oil. A gallon of that make-up oil was added only 1200 miles before the oil change. So, assume the actual wear metals are probably between 2 and 3 times what is shown. If so, it means my silicon is between 26 and 39ppm, which is bad. My main concern was the copper - it was very high last time. I assume it was due to a new oil cooler that was installed before the oil change that the previous sample was based on. The oil cooler ran for maybe 2k miles on the oil that was installed after the reseal and oil cooler change job. That oil was dumped and not tested. The next load of oil was run for almost 10k, and that gave the high copper reading. The oil cooler is a steel assembly that is furnace brazed in a dry hydrogen atmosphere, with pure copper used as the braze metal. It flows so well that it left a thin film of copper covering virtually every surface, even far from any joint. Evidently a lot of the copper made it into solution in the oil before it became passivated.
The oil consumption is due to leakage past the turbo oil seals, which is in turn due to poor turbo oil drainage. I've been meaning to address this for the past year, but it requires installing a turbo drain bung in the pan just below the pan rail. That, of course, means removing the pan. I've been putting it off for that reason, but after having to add a full gallon of makeup oil I finally decided it was time. Fortunately, I was able to acquire a beat-up but useable pan to swap in place of my pan on the engine. This way I could continue using the truck while I install the bung(s) in the pan, sand it, and paint the interior with Glyptal 1210 and the exterior with Cummins beige acrylic urethane.
Even though the oil that is in the sump now will only get a few k miles on it before I swap the pans again I still plan on running a UOA on it. In the brief time it will be used I shouldn't need to add any make-up oil. Then I can get a better idea of how much contamination it's accumulating per 1k miles.
I will say this: even with the amount of make-up oil I added and the ok-ish insolubles, the crankcase and oil pan were absolutely disgusting. The company that owned the truck this engine came out of did 5k oil & filter changes. When I dropped the pan to inspect it prior to the swap it looked very nice and clean. Likewise, when I had the tin and head off to re-seal the engine everything still looked decently clean, for a diesel. I was doing 6k OCI's at that point. This time, with 16k on the oil, the crankcase was quite scuzzy. No sludge, but scuzzy nonetheless. Even though the insolubles and other test results were ok, Im still not going to deliberately run long OCI's. I'm going back to 6k miles.
The wear metals look really low due to the large amount of make-up oil. A gallon of that make-up oil was added only 1200 miles before the oil change. So, assume the actual wear metals are probably between 2 and 3 times what is shown. If so, it means my silicon is between 26 and 39ppm, which is bad. My main concern was the copper - it was very high last time. I assume it was due to a new oil cooler that was installed before the oil change that the previous sample was based on. The oil cooler ran for maybe 2k miles on the oil that was installed after the reseal and oil cooler change job. That oil was dumped and not tested. The next load of oil was run for almost 10k, and that gave the high copper reading. The oil cooler is a steel assembly that is furnace brazed in a dry hydrogen atmosphere, with pure copper used as the braze metal. It flows so well that it left a thin film of copper covering virtually every surface, even far from any joint. Evidently a lot of the copper made it into solution in the oil before it became passivated.
The oil consumption is due to leakage past the turbo oil seals, which is in turn due to poor turbo oil drainage. I've been meaning to address this for the past year, but it requires installing a turbo drain bung in the pan just below the pan rail. That, of course, means removing the pan. I've been putting it off for that reason, but after having to add a full gallon of makeup oil I finally decided it was time. Fortunately, I was able to acquire a beat-up but useable pan to swap in place of my pan on the engine. This way I could continue using the truck while I install the bung(s) in the pan, sand it, and paint the interior with Glyptal 1210 and the exterior with Cummins beige acrylic urethane.
Even though the oil that is in the sump now will only get a few k miles on it before I swap the pans again I still plan on running a UOA on it. In the brief time it will be used I shouldn't need to add any make-up oil. Then I can get a better idea of how much contamination it's accumulating per 1k miles.
I will say this: even with the amount of make-up oil I added and the ok-ish insolubles, the crankcase and oil pan were absolutely disgusting. The company that owned the truck this engine came out of did 5k oil & filter changes. When I dropped the pan to inspect it prior to the swap it looked very nice and clean. Likewise, when I had the tin and head off to re-seal the engine everything still looked decently clean, for a diesel. I was doing 6k OCI's at that point. This time, with 16k on the oil, the crankcase was quite scuzzy. No sludge, but scuzzy nonetheless. Even though the insolubles and other test results were ok, Im still not going to deliberately run long OCI's. I'm going back to 6k miles.
