This 1.9 engine is blowing oil up through the valve cover hose into the air cleaner. It's not much but enough to allow oil to drip under the carburator. It's been doing this for years and I've basically ignored it. It's my understanding these engines have no PVC valve. Any idea what causes this to happen and is there any other type of crankcase ventilation on these engines?? (still running strong after 265,000 miles)