Does a '75 240D have a Cyclone Separator, or something similar...? That's a device that looks like a black beer can that is located between the tube coming out of the top of the valve cover and the tube going into the air intake.

The intent is to burn crankcase gases, but not oil. It allows the noxious gasses to get burned, but makes the liquid oil drip back down into the crankcase.

My guess - and I am no expert here - is that crankcase oil is making it's way out through the tube leading from the valve cover and into the intake (regardless if there is any kind of separator or not). That's what's fueling your runaway condition.

I don't understand why it would do this when the front of the car is lower. Maybe a high oil level is causing frothing up front, and that's making it's way into the valve cover area...?

Is the oil level on the high side? Perhaps overfilled?

Just some ideas.

- Patrick

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1982 240D. 198k, Marine Blue/Blue, 4 Speed, Crank Windows, No Sunroof, No Rust, No Oil Leaks
2001 TDI. 197k, Lagoon Blue/Black, 5 speed, Chip, G60/VR6