My 2006 NP diesel has about 350,000km on the clock. A few months ago I noticed quite a bit of oil sprayed around under the bonnet, the source being a very wet air intake. Checked the air filter...absolutely clean, although oil present in the chamber leading to the manifold. Couldn't understand how the oil got to the intake through the filter without fouling it! Research proved fruitless, so off to the local mechanic. Diagnosis...I forget the precise logic but a badly-fouled intake manifold was mentioned. I couldn't follow his logic, but accepted his suggestion of fitting a catch-can to intercept the oil. He showed me a photo of intake manifolds in a fouled state as an example. Job done. Not cheap but no option.
A few days ago, I was alarmed to notice similar deposits in the air intake, though not as bad.
Cleaned it thoroughly. Checked the drain-cock under the catch can... completely empty.
QUESTIONS:
1.Where is the oil coming from?
2. How can it foul the intake without affecting the filter? ie. by what path?
3. Is high crankcase pressure a factor?
Don't know if it's relevant, but I dragged a couple of heavy trailer-loads of firewood for 25 km
on the previous two days.
Although I can just keep occasionally cleaning the intake when necessary, I need reassurance that this is not an indication of a serious problem developing, and would really, really appreciate
an understanding of the issues.
A few days ago, I was alarmed to notice similar deposits in the air intake, though not as bad.
Cleaned it thoroughly. Checked the drain-cock under the catch can... completely empty.
QUESTIONS:
1.Where is the oil coming from?
2. How can it foul the intake without affecting the filter? ie. by what path?
3. Is high crankcase pressure a factor?
Don't know if it's relevant, but I dragged a couple of heavy trailer-loads of firewood for 25 km
on the previous two days.
Although I can just keep occasionally cleaning the intake when necessary, I need reassurance that this is not an indication of a serious problem developing, and would really, really appreciate
an understanding of the issues.
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