2002 Jeep Wrangler Q&A
2002 Jeep Wrangler Question: Engine knocking/ticking
Your oil filter has a anti drain back valve. This valve is probably defective allowing oil to drain back to the oil pan, thus basically losing prime. When you start the engine, the top end is "Dry", which would cause the ticking noise. Another possibility is you are hearing "piston Knock". Piston knock is not harmful to the engine. As the engine warms up, the piston expands, thus the clearance between the piston and the cylinder is less. This is a result from normal wear, especially if you have a 2.5 - 4.0l engine. Your oil pressure, 40 psi @ idle is on the high end of normal. Normal oil pressure at idle can be as low as 5psi. At 3000 rpm, normal is considered to be between 25 and 80 psi. - Johnny Mopar
I recently purchased the jeep. couldn't worry about the problem too much because of the price and excelent condition of the body. the gentleman that owned it, let his son drive it and he drove it o...
A ticking type noise may be noted from the engine area due to an exhaust manifold that has cracked where the pipes are welded; cracked manifolds should be replaced.