These engines ran a plastic valve cover that was a failure the day it was installed. AMC removed using a few of the bolts - why I'll never know - which allows the plastic to 'bulge' - allowing the gasket to fail in areas. The aging plastic warps - adding to the number of gasket failures. There have been a number of engine fires due to these Design Flaws. These engines also develop a lot of crankcase pressure - in part due to the lack of 'windage' area inside . With every crank rotation - the pistons 'pump' the inside air - eventually weakening the rear main seal - and front seal around the crankshaft. I would look there for oil at the front seal that is then blown back on the engine . The 4.0 engines around 1989 had some 'upgrades' to the PCV - Pollution Contorl System - which helps but - with time and mileage - the 258 / 4.0 will push oil out of the engine thru seals / gaskets. The PVC valve itself should be kept up - as allowing the engine to draw air in will weaken the seals rapidly . As this continues - the seal 'Lips' develop tears which can only be remedied by replacement. This also occurs if the vehicle has sat a long time - allowing the seal lips to go dry . When the engine is started - they tear . This also happens to the TorqueFlite transmissions front seal ........ ask me how I know ......... . Brien. NEW YORK Subject: mail Digest for 17 Oct 2004 in hour 20:00 Date sent: Sun, 17 Oct 2004 20:05:18 -0700 Send reply to: mail-From-<# print(JADDR); #>@amc-list.com " My daughters 83 Spirit (258 engine) appears to be " leaking oil out of the dipstick tube. Is this " possible? I haven't been able to confirm it but the " oil is on everything behind the end of the dipstick " (ie the top of the distrib, etc). It's definitely not " coming from the valve cover or from the base of the " distrib (new gasket). Any suggestions apprecitated. first thought - plugged pcv valve, forcing pressure to build up in crankcase. possible? _________________________________________ _____________________ __________ Andrew Hay the genius nature internet rambler is to see what all have seen adh@xxxxxxxxxxxxxxxxx and think what none thought