Im having an oil leak which i believes is come from the head gasket but i had different people looked at it and they said its not my head gasket,if it aint smoking,over heating and lagging.....but the guy who i bought the car from said the #4 cylinder is reading at 85 and the other 3 is reading at 160. So i cant tell where this oil leak is coming from.it only leaks over night on my drive way....any inputs on this lil prob

 

If it was a headgasket you'd be leaking coolant, hence the white smoke from exhaust.

Clean every drop of oil including undercarriage then let it sit overnight like you said it leaks, then check again, it'll be easier to spot.

 

So a leakdown test, that compression number is too low.

 

Get a bottle of uv dye and uv light, it will help you trace where the oil is coming from.

http://www.amazon.com/Tracerline-Dye...ef=pd_sim_hi_1