I noticed that my Jeep has been making a distinct clapping noise any time the engine is not up to operating temperature. It sounds worst on cold mornings, but becomes quieter as the engine warms up. The noise is RPM dependent, so I'm assuming it has something to do with the engine. The noise is not audible when the engine is idling in park, but quickly shows up as soon as I put the car in gear and add gas. My father and I think that a slightly loose rocker might be the cause of the noise, but we're not sure. A mechanic friend of his told him that our jeep has self adjusting rockers so it can't really be fixed without replacing it. I've never heard of such a thing so I'm having a hard time believing it. The really confusing part is that it only makes noise when the car is in gear and the engine is under stress, making no noise when it's just idling, even when the engine is revved. Since purchasing it 5 years ago, we have been careful to do regular maintenance on our jeep so I'm somewhat surprised by it. We really need it to the 2 more years of commuting to college so any help or advice would be greatly appreciated.
1998 Jeep Grand Cherokee Laredo
4.0L I6 with stock 4 speed transmission