Have a JD with 18 hp v twin FH531V that is leaking oil  badly. It appears to be coming out of  the lower  crankshaft seal. But not when its running but after it has been running 15-20 minutes. Took  off the pto, checked and replaced the seal  but  still doing this. I'm beginning if this might be caused by too much crankcase pressure. I did think to loosen the dipstick when this started to leak again but does the dipstick actually seal that well  to cause the pressure to build up if  the breather valve is malfunctioning. This leak has me about nutz