I have a question about oil for a Deutz powered Bobcat. I bought the machine with 4300 hours. When I looked at it, it was very hard to start. I had a very good shop go over everything. Two cylinders had high, but within spec compression, and the other two had low but within spec compressions. The starting turned out to be a timing belt, which was replaced. All the filters were replaced, and the oil changed. Within twenty to thirty hours of operation, the oil turned dark. I just changed the oil and filter after about 100 hours, and it turned dark again quickly. The engine starts and runs perfectly, and develops good power. The operating temp is normal. I know there are two schools of thought on dirty oil. The first is that oil isn't supposed to get dark. The other is that the fact that the oil is dark means that it is doing its job, and it's no cause for concern. What is the most likely cause for the dark oil? Is is blow-by past the rings? I tended to discount that because the engine doesn't burn much oil at all. I plan on sending a sample out for analysis, but I'm trying to figure out what to expect.
Oil
- Thread starter lesgawlik
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SkidRoe
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Every diesel engine that I have had anything to do with in the 30+ years that I have been fooling with them turns their oil black with in a very short number of hours after an oil change. The statement that you make above about the oil getting dark because it is doing its job is right on the money. All detergent oils contain additives to soak up nearly all contaminats that make their way into the engine.
Some blow-by in a diesel is inevitable, due to the cylinder pressures generated during combustion. Some soot generation is also inevitable, which is what is turning your oil black.
Use good oil & filters, change them both regularily, and if you are still worried, get an oil analysis done at each oil change. This is probably the best indicator of any impending engine doom.
Some blow-by in a diesel is inevitable, due to the cylinder pressures generated during combustion. Some soot generation is also inevitable, which is what is turning your oil black.
Use good oil & filters, change them both regularily, and if you are still worried, get an oil analysis done at each oil change. This is probably the best indicator of any impending engine doom.
Thanks, SkidRoe. That's what I thought, but I was told the oil shouldn't get that dark by a friend who seemed to know a lot about T200's. I wondered about that when he said I should check the antifreeze.
