Help Engine Knock 4.0L

I have a 1993 Cherokee. The engine sounds like a diesel. It is less noticable standing in front of the vehicle and louder from the sides and underneath. It doesnt affect performance at all. and gas milage is normal. Oil is full and doesnt burn any or leak any. Exhaust is normal. Also when it shut off sometimes the engine rattles. Please help.

check for a cracked exhaust manifold... very common

Mileage would be good to know.

Besides Ex. man, I've seen cam issues on these with high mileage and in several cases a severe case of carbon build up.

I had an 93 with the 4.0 that never so much as ticked. Had 145K when I let it go.

Yes whitecopter, how many miles? Is it the 4.0 Liter or the 2.5?

It is the 4.0L with 158k. Like I said the thing runs beyond great it just makes that annoying sound. I recently drove it from oregon to Lousiana with out evens ome much as a sputter or ping but made the knocking the whole way. Gnerally cant hear it when on the freeway.

it is probably piston slap. it won't hurt the life of the motor. mine does it when it is cold in the morning. mike

Mine did the same thing. Pretty severe knocking though. I tightened up the torque converter bolts and it stopped. Although it still sounds a bit like a diesel. My mechanic said it sounded like a loose wristpin. I wouldn't worry about it, these engine are notorious for knocking sounds. Doesn't seem to affect the life of the engine or cause any problems. Check the converter bolts though, mine also sputtered when i turned her off :grinyes:

x2 for cracked manifold or loose torque converter bolts behind the dust shield.