Most cars use a design with overhead cams and a valve cover for service. Over time, the gasket that seals the valve cover to the head wears and eventually fails. Typically you will see leaking oil - but sometimes the leak occurs in the spark plug wells.
This is a '93 Saturn SW2 - maintained not so well.
Purge Solenoid Damaged (stuck closed)
I suspect the valve guides are worn... I have good compression, but she eats oil (not enough to smoke though)
Automatic with classic reverse hesitation (common for this tranny)
Rear Passenger window not working - stuck slightly open
Traction control (with an overide button in the cab :P)
Oil service interval -- wayyy too long (which forced me to replace the timing chain and guides)
Odometer stopped years ago at 68K miles
My parents owned this car - and I kept her running. Normally, the T-chain lasts forever. Unless you let the oil level get low, in which the guides literally explode. It was driven without an upper guide (and only partial side guide) for several thousand miles - which nearly ate a hole in the valve cover.
I do commend the design... Even with everything going wrong... she just refused to die. All of that oil in there, and she kept on running. Even with the T-chain rattling away inside (slowly eating the VC) - she kept on running. I was sad to see her go, but the replacement was an '06 Altima Special Edition... BTW, the 2.5l Nissan engines for the '06 models are being recalled (all 87,000 of them) for replacement (poor piston ring selection).
Step 1: Materials
Valve Cover Gasket Kit ($13 at autozone, big box with two tubes of RTV and 11 neoprene bolt seals)
--- alternatively, you can buy the preformed gasket for about $30 - if you have the black polycarbonate valve cover, you MUST use this preformed gasket... it saves some time/work in the end though.
Torx Bit - can't remember the size
Socket Set (I think you only need a 10mm)
Flat Heat Screwdriver
Brake Parts Cleaner
Rags, turkey bastor -- to clean up oil
If your spark plug wells were flooded like mine you may want to replace:
Spark Plug Wires