JMO413 Posted April 21, 2019 Share Posted April 21, 2019 Just looking for suggestions on this engine noise. This is from cold start. This is fully warmed up. This noise has me fully baffled. The truck has always been a little noisy. Just looking for thoughts of what I might be missing. Backstory: The truck has always been a little noisy. Sometimes the noise will almost go completely away. Sometimes it sounds like something is trying to escape. With a mechanics stethoscope you can hear a tick everywhere on the engine. Head all the way to the oil pan but nowhere is any louder than the rest. Noise is still there without a belt. Oil pressure is at 50+ psi cold and drops to 25psi completely warmed up at idle. Goes back up to 50+ when driving. Ran marvel mystery oil 1000 miles and just put in fresh Rotella 15/40 with a wix filter. Any thoughts would be greatly appreciated. Link to comment Share on other sites More sharing options...
JMO413 Posted April 21, 2019 Author Share Posted April 21, 2019 I should also add, rocker arms are all torqued to spec and all getting a good amount of oil from pushrods. Link to comment Share on other sites More sharing options...
Minuit Posted April 22, 2019 Share Posted April 22, 2019 I don't have an answer for you, but I will say that every Jeep 4.0 I've listened to in person has had this noise to some level. My '91 has always sounded similar to your cold start video but not quite as loud. It too has good oil pressure and the lifters on it seemed fine when I had the valve cover off recently. Link to comment Share on other sites More sharing options...
kryptronic Posted April 22, 2019 Share Posted April 22, 2019 4 minutes ago, Minuit said: I don't have an answer for you, but I will say that every Jeep 4.0 I've listened to in person has had this noise to some level. I concur 100% with this. The top end on the 4.0L develops this type of noise after only a couple thousand miles. I don't really hear anything abnormal in your videos, although the tapping does sound a little louder than usual. Heavier weight oil tends to quiet it down a bit. Link to comment Share on other sites More sharing options...
JMO413 Posted April 22, 2019 Author Share Posted April 22, 2019 I was kind of thinking that. I had 10/30 in it before the last oil change. The 15/40 didn't seem to change anything. I think I will just drive it until the inside parts find their way out. After pricing machine shop fees and rebuild parts a reman isn't really much more. Thanks for the input. Was just wondering if there was something I was overlooking. Link to comment Share on other sites More sharing options...
Jeep Driver Posted April 22, 2019 Share Posted April 22, 2019 You and this guy below- I suspect the same problem, worn cam and lifters. Link to comment Share on other sites More sharing options...
sinkrun Posted April 22, 2019 Share Posted April 22, 2019 I am going to say piston slap very common on the older 4.0. Link to comment Share on other sites More sharing options...
JMO413 Posted April 22, 2019 Author Share Posted April 22, 2019 1 hour ago, Jeep Driver said: You and this guy below- I suspect the same problem, worn cam and lifters. That is what confuses me. The noise is no louder along the cam/lifter area of the block with a stethoscope. If I was sure it was a cam/lifter noise I would replace it/them. 1 hour ago, sinkrun said: I am going to say piston slap very common on the older 4.0. That is truly my guess from all the reading I have done. I'm still confused you can't hear it through the block with a stethoscope. Link to comment Share on other sites More sharing options...
Jeep Driver Posted April 22, 2019 Share Posted April 22, 2019 5 minutes ago, JMO413 said: That is truly my guess from all the reading I have done. I'm still confused you can't hear it through the block with a stethoscope. Based on the sound on your vid................ It sounds like it's the same no matter where the camera panned the VC....is this correct? If this is correct then you would have to conclude that all 6 pistons are slapping and I cannot believe that. Clacking sounds like rockers to me, not piston slap. Link to comment Share on other sites More sharing options...
JMO413 Posted April 23, 2019 Author Share Posted April 23, 2019 22 hours ago, Jeep Driver said: Based on the sound on your vid................ It sounds like it's the same no matter where the camera panned the VC....is this correct? If this is correct then you would have to conclude that all 6 pistons are slapping and I cannot believe that. Clacking sounds like rockers to me, not piston slap. The more I listen to the video the more I think you could be right. I guess if I ever get the clutch and tranny back in is time for a cam and lifters. Link to comment Share on other sites More sharing options...
JMO413 Posted June 16, 2019 Author Share Posted June 16, 2019 Well part of the noise was the cracked exhaust manifold for sure. Replaced it and the broken stud. The loud tick is gone just valve train noise now. Link to comment Share on other sites More sharing options...
omega_rugal Posted June 17, 2019 Share Posted June 17, 2019 bent pushrods? in an old engine like that i won't expected to be still straight, a small gap can make suck click noise... Link to comment Share on other sites More sharing options...
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