Looking at an older Mustang excavator (circa year 2000) with an 1800 hour Yanmar engine. I noticed some blue smoke out of the exhaust and when I pulled the oil cap when it was running the oil was spitting out. Blow by? Or an indicator of a strong oil pump? Any insights would be helpful.
I had a similar problem in a different engine and the crankcase vent had clogged. That would be the first place I looked.
Put your hand over the opening. Do you feel pressure too? Sounds like a lot of blow by then.
The cap won't tell you much. Look at the vent tube, is it wet with oil and clean around that area? just a little oil and dusty build up? a little flow of air and smoky steamy air? puffy? or a good strong flow of air? if the vent tube is blocked, then the oil will leak everywhere out of some engines. Did you check the oil level also? even look around the oil fill cap, if it's all dusty like it hasn't been washed in a hundred operating hours, then it's probably not using that much oil. Be suspicious if it's recently wiped clean or pressure washed.
Great points! The last point about being suspicious...oddly, the machine was spotless.
Is there always blue smoke?