Tracking down an oil leak

[402Z]

When I first bought the car it was leaking oil pretty bad. Had the header stud oil leak fixed and it minimized the leak a ton but it is still dripping in one spot. I looked under the car and it is leaking right where the engine meets the transmission. Could it be the rear main? I know Marc says he has never seen a factory installed rear main leak but I am not leaving that possibility out. Let me know what y'all think I'll put a picture of where the oil is landing when it leaks. Thanks.

[TX '90 ZR1]

See this from Marc Haibeck. 17274
I would bet on the oil pressure regulator cover leaking and running back to where it is dripping.
Check torque on the pan bolts and everything else you can get a wrench on also.
Things tend to loosen over time and heat cycles.
:cheers:

[1991 Corvette ZR-1]

The rear main seal may not be leaking, however the bolts that fasten a housing the seal resides in can loosen and allow a leak. I did a clutch swap recently and found all 7 bolts were loose and could be rotated with my fingers left or right with no resistance. The area was also wet and it explained why the back of the oil pan was always wet in appearance.

[402Z]

Went under the car yesterday and I believe my crankshaft position sensor is leaking. The wire going to the connector was wet with oil and when I unplugged it the prongs seemed to have oil on them as well. I will replace that and fingers crossed it will fix it since every other potential leak is a pain to get to lol.

[Young1]

FYI. The sensor you buy will not be bolt in. It has to be ground and shaped to fit to machined engine block surface. Also apply RTV for extra oil sealing.

[-=Jeff=-]

Buy the one from Jerry.. OEM exact replacement

https://www.jerrysgaskets.com/sensor-crank-position-new-1990-95-1f4/

[Paul Workman]

Another possibility(?) is the valley drain pipe outlet? The injector housing bolts on my LT5 were quite loose (the first time I had the plenum off). Oil had collected in the area under the starter and was draining via that drain tube to leak beneath the bottom of the bell housing area. (Some BLUE Loktite on the bolts ended that leak (and some others) forever more.)

[jss06c6]

Another possibility(?) is the valley drain pipe outlet? The injector housing bolts on my LT5 were quite loose (the first time I had the plenum off). Oil had collected in the area under the starter and was draining via that drain tube to leak beneath the bottom of the bell housing area. (Some BLUE Loktite on the bolts ended that leak (and some others) forever more.)YES!! as Paul said, check the pipe coming down between the flywheel and the block.

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