I have a1994 Nissan 2.4 XE pickup with 138000 mi. It has developed a leak and I can't find it. It looks like its in the front but we changed the oil pan gasket seems to have slowed it down. I put 20/50 oil in it after a lifetime of 10/30 Castrol Syntec.It isn't the front seal cause I can't see any oil their. But the Alt.on 1 side and some kind of funny looking valve under the oil filter on the other side have quite a bit of oil on them.I just drained the oil out and put in DELO 400 15/40. This truck runs great I just need to find the leak. Thanks Dropitby