Oil blowing out of filler cap - 1999 BMW 318 ti

You may be having problems with the crankcase pressure regulating valve (PCV). If this is clogged or malfunctioning, pressure can build up inside the engine and blow oil out the filler tube.

Hi dose the car still have power? And is it smoking ? If not check the Oring on the filler cap see if it is still ok if not the oil will blow past it

yeah, it's supposed to do this, so keep the cap on when the engine is running

there will be,if it shoots the cap off while you are unscrewing it then you might have an issue,but oil will come out with car running and cap off

I doubt the oil is boiling in the sump or your engine would show signs of over heating. Change the PCV valve in the valve cover as it may be stuck closed causing internal pressure to build up and escape through the filler cap.

Buy a new oil filler cap......

The engine breather pipe seems to be blocked.
It may also damage the oil seals.

The oil level may be too high.
Is the filler cap tight?
blow-by in the cylinder piston rign area. A wet test of engine compression will detect this.
A bad had gasket. Engine will be over heating as water is being used up during combustion.
Bad head gasket. Could explain white smoke in exhaust.

If the engine is overheating I would be suspecting a problem in the head area.

Good Luck. SnugglePants

Check your PCV valve. Its the device that provides ventilation to the crankcase and valve covers. If its clogged or non functional it will cause the engine to **** or blow air from an area with less resistance, which is probably the filler cap. As its blowing air out of the engine it will shoot a little bit of oil with it