Hello i have a 1973 beetle when i drive more than an hour at about 80km/h the oil pushes up on my dipstick and start to leak at the overflow is that normal?
No it is not. It is a symptom of too much pressure in the crank case. That may have several causes - bad piston rings, allowing blow by from the combustion chamber to over-pressurize the crank case and force oil out. It may be TOO MUCH oil was put into the engine. A good sign of that is frothy oil. I'm not that familiar with VW engines, but it should have some sort of PCV or positive crankcase ventilation, if that is plugged up the pressure in the crank case will find another path to exit, like a dipstick tube. (this would be the easiest one to look into and fix.)
Worn engine check direct intake vacuum with a gauge at idle 19-21Hgin Ok
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