I can only comment on the cause and effect ... not the reasons therefor.

Fixing my air leaks at the dipstick tube and the oil fill tube cured a
problem that presented itself like a vacuum leak would.

Mike

Larry Alofs wrote:
> Can someone explain why a vacuum leak into the crankcase can affect
> drivability?
>  I thought that the crankcase ventilation system had some type of
> orifice to control the amount of air that goes into the intake by that
> route.
>
> Larry A.
>
>
> Mike Collum wrote:
>
>> Without a good O-Ring where the dipstick tube goes into the case, and/or
>> a good rubber seal where the dipstick enters the tube, you can have a
>> vacuum leak which would cause driveability issues.
>>
>> I even found on my '84 that the oil fill tube had a bad seal where the
>> plastic part attaches to the metal part that caused poor running.
>>
>>
>> Mike
>>
>>
>>
>> Roger Sisler wrote:
>>
>>> I got a lifetime  suply of 0-rings. Can I pull the tube out and
>>> replace the
>>> ring? What if the rings I have dont fit. Can  I just press the tube
>>> back in?
>>>
>>
>