Strange engine noise

CowboyTJ

Member
Original poster
Joined
Oct 3, 2021
Messages
72
Location
The South Coast of Mississippi
1999 4.0, had it about two years. From the beginning, about 30 sec. after startup a rattle would begin, low at first then get louder and then fade to almost nothing.
Using a stethoscope with a long probe I can not positively locate the sound. Not from the head, timing chain cover or anyplace on the block, even removed valve cover.
All neighborhood shadetree mechanics have different opinions. Such as; valves, piston slap, wrist pins, timing chain, even externals like alternator, water pump etc.
In the two years I've had it, put less than 10,000 mi. and has not gotten any worse. The guy I bought it from says, it's done it all the time he had it.
I guess I have resolved to just let it be. It doesn't seem to be getting worse and eventually it will show itself.

My question is, has anyone else had this "Gremlin" ?
 
1999 4.0, had it about two years. From the beginning, about 30 sec. after startup a rattle would begin, low at first then get louder and then fade to almost nothing.
Using a stethoscope with a long probe I can not positively locate the sound. Not from the head, timing chain cover or anyplace on the block, even removed valve cover.
All neighborhood shadetree mechanics have different opinions. Such as; valves, piston slap, wrist pins, timing chain, even externals like alternator, water pump etc.
In the two years I've had it, put less than 10,000 mi. and has not gotten any worse. The guy I bought it from says, it's done it all the time he had it.
I guess I have resolved to just let it be. It doesn't seem to be getting worse and eventually it will show itself.

My question is, has anyone else had this "Gremlin" ?

Checkout my post from yesterday, curious if the noise I'm hearing is similar to yours? I've also got a 1999 4.0.

https://wranglertjforum.com/threads/another-whats-this-noise-from-my-engine-thread.70200/