How to diagnose oil leak in 97' 4 cyl

[caveman017]

Ive got a 1997 4 cyl with about 140k miles on it. The past few months or I so I have noticed some oil leaking onto my driveway. Looking underneath the car, I found a lot of oil on the bottom covering it. I noticed that right behind where you put the oil in at the top, I saw some oil as well. I'm thinking it may be the valve gasket, but I'm not sure.

Any way to diagnose this?

[500KCamry]

Try to retorque the four nuts that hold the cover down. Think they are 30 mm on the spark plug tubes.

With mine, I found a lot of oil on the rear of the block because of this type of leak.

[96paseo]

If your timing covers and acessory belts have oil on them, you may have leaky seals on the crank, cam or oil pump. You can buy a couple of cans of brake parts cleaner and spray down the oily area then drive the car and check where the leak is starting.