Quick question

[Tom and Maria]

I know I should know the answer but, until I've taken something apart I never can understand it...

Will a new crank stop oil leaking through the back of the enigne? What is it that wears, the crank, the block, or some bearing?

Thanks,

Tom

[bmcecosse]

Well - yes the main bearings can wear which allows excess oil to flood the labyrinth 'seal' - but the real cause of leakage there is pressure in the crankcase pushing oil out past the labyrinth...... So - look first to the crankcase breathing - it MUST have a pipe to the inlet on the side of the carb - or to the air cleaner, although that is a very poor second choice. And of course - if the bores/rings/pistons are worn - nothing will seal it. Simple test - hot engine idling - remove the oil filler cap and rev up - is there a plume of smoke/fume??

[Tom and Maria]

Yes, the breathing is fine. I tapped the manifold earlier this year and it has almost completely stopped the oil leak, it now only loses any if I drive faster than 55.

Thanks,

Tom

[bmcecosse]

Oh well - the answer is in your hands ! Good mpg speed too........