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Oil / antifreeze dripping out of Crank vent tube

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Took the car, a 57 Tbird with the 312 engine,  for a short drive to warm it up.  Later I noticed some drips of oil on the ground, It was brownish color - maybe antifreeze mixed with the oil, coming out of the crankcase ventilation tube at the back of the engine.  Maybe related, when adjusting the timing I put a vacuum gauge on the carburetor but it did not show much vacuum.  The engine seems run smooth and I did not notice any issues when driving.  Any thoughts on what the cause is- leaking heads?  Thanks

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A lot of condensation builds up in a crankcase, especially with a road draft system.  If your road draft tube has any rust in it, which it probably does, thanks to the aforementioned condensation, the water that drips from it will look like oil.  If you're truly concerned that it could be antifreeze, the first thing I'd do is rent a radiator pressure tester from a parts store, follow the instructions, and see what you come up with.  If it's running well and not running hot, then you probably just need to take a longer drive to get the oil really hot.  15 minutes around town won't do it.  


Regarding engine vacuum: If you connected your gauge to the port for the vacuum advance, there's a good chance it's a timed port, meaning it doesn't see vacuum until the throttle is cracked open.  

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