Thought I would check the condition of the MAF sensor and throttle body and I was surprised to see a shallow pool of engine oil when I opened the throttle plate, is it normal? Posted via the PriusChat mobile app.
Yes. The Atkinson cycle engine holds the intake valve open during the first 1/3 of the compression stoke. This pumps fuel/air and some oil on the cylinder bore back into the intake manifold. This mix accumulates down there normally.
The intake manifold has a sort of tank in it on the bottom to help with this effect but oil will still be there. Not hurting anything. Spray some lubricant on that throttle spring.See the hose at the top of the throttle body that's the pcv hose it dumps fumes back in the TB. Pull the hose off and flush that input out with carb cleaner but while holding the butterfly open stuff a rag in the bore so it picks up the crab cleaner. Rag not paper towel. And dont forget the 10 mm throat clamp under the air cleaner make sure you tighten it. The amount of sludge the pcv pumps into the TB is determined by what quality oil you use.
Is some of this coming through the PCV system as oil mist or droplets, as it does in the Gen3? This is one reason many Gen3 owners put in oil catch cans, a.k.a. oil-air separators. One reason for this is that oil subsequently going through the combustion chamber, but not fully burned, might be a contributor to the clogged EGR systems in Gen3. This part isn't a problem in the Gen2, which lack the particular parts that clog in Gen3. But the PCV oil catch can might still have some possible benefit on Gen2.
The one on the rear of the throttle body. You can pull both of them off just make sure they go back on the same port they came off. Then when there off stick the carb cleaner stem in the pipes and flush away. make sure you stuff a cloth in the tB throat though.
