Been chasing an oil leak at the back of a 272 Y-block in my 55 Ford. I thought it was the rear main, but I changed the oil yesterday, today came home ,didn't start the engine, just rolled it out onto the driveway. Got back a few hours later and found a good size oil puddle under the car. Will the rear main leak with the car just sitting????? Or should I be looking at something else. I've had it running after changing the oil and filter to check for leaks and didn't see anything......
Being as Y-blocks have an external oil pump, you might want to check the oil pump gaskets(BOTH OF THEM :bottom cover to pump/ pump to block), the external lines(especially the line-to-pan gasket) the seal where the line enters the pump, & the seal(usually copper O-ring)under the oil pressure relief spring plug. Not very often, but have seen cracked pump housing. Put the car up on stands, pressure wash the bottom of the engine, possibly use some form of dye-checker spray to check for cracks, then (with lots of light) start the engine & look for leaks. I know that this is a little over-the-top, but it pays to be thorough! I hope this helps. While you're at it ; use the dye-check on the pan as well, as they also have been known to get cracked.
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