MT Jeep Posted June 7, 2019 Share Posted June 7, 2019 Hi All, This is my first ever post on this forum or any forum for that matter. I have an 87 Comanche 4.0 pioneer that has a bad ticking noise. It has been doing this noise for the last 6 months I've owned the truck. I've run thicker weight oils, various additives and they did little to help. The noise is strange in that it is intermittent and only seems to get bad after the engine is fully warm. Did the rear main seal two months ago and didn't notice any metal debris in pan. It doesn't get noticably audible until oil pressure is under 40. Seems to be worse at idle(or just easier to hear) or when coming to a red light after driving at higher speeds. I have had two people listen to it and one believed it was most likely a bad lifter. The other seemed to think it was a possible exhaust issue. I believe that I do have some exhaust leak, but I don't think it could be the cause of metalic click noise. I am leaning toward it being the lifters, but I also know these engines can develop piston slap. Before I get into any fixes is there anything that can be done to help determine if the tick is a lifter, piston, or possible exhaust? What do you guys think it sounds like? I have attached a short clip of the engine ticking when fully warm. Thanks for any advice you may have. VID_20190522_091052028~3.mp4 Link to comment Share on other sites More sharing options...
Minuit Posted June 8, 2019 Share Posted June 8, 2019 I hear an exhaust leak too, but the tapping sounds too sharp and metallic for it to be an exhaust leak, to my ears anyway. If it was an exhaust leak, you'd know because it would be much louder under throttle, especially in high gear and high engine load. An exhaust leak might sound like a "click" but it will have a definite tone of air escaping to go along with it. Link to comment Share on other sites More sharing options...
87MJTIM Posted June 8, 2019 Share Posted June 8, 2019 try a mechanic's stethoscope to listen along the valve cover and cylinder head to locate where the sound is coming from. That will help isolate a tap or a leak. Link to comment Share on other sites More sharing options...
MT Jeep Posted June 8, 2019 Author Share Posted June 8, 2019 Thanks, I appreciate your replies. I have tried using a stethoscope and couldn't pinpoint the noise to a precise source. It seems to have a general tap tap tap wherever I place it. Listening by ear it seems to be loudest near the rear of the valve cover. Any thoughts as to why this noise is intermittent instead of being steady? Engine has 180,000. Link to comment Share on other sites More sharing options...
13 Legion Posted June 8, 2019 Share Posted June 8, 2019 Watched a vid this morning on piston slap. I’ll sum it up for you. He has an earlier vid showing him searching out the noise. 89 Cherokee 4.0. Lifter tick. He diagnoses. Takes valve cover off. Checks rocker arms, pulls plugs, checks compression, he does at least verify what cylinder is making the noise . He ends up changing out all lifters. On a 4.0 you have to remove head. Apparently you can get them out on a 2.5 without head removal. Well he puts it all back together and... same noise. You can watch that video if you want. He finally gets it diagnosed as a worn piston after running a battery of tests literally. In this vid he just shows you how he went about swapping piston out.. yes a PITA but he keeps it all in perspective. Good luck man. Link to comment Share on other sites More sharing options...
JMO413 Posted June 8, 2019 Share Posted June 8, 2019 Mine sounds exactly like yours. It it dead quite on start up and then this nose appears. I changing my exhaust manifold next week. I know I have a broken stud in the back. I'm guessing my manifold is cracked also. I will let you know if it changes anything. I'm also pulling the oil pan to do the rear main and oil pan gasket beacuse both are leaking. While I have it if I'm going to have s look at the Piston skirts and timing chain. I will report back. Link to comment Share on other sites More sharing options...
MT Jeep Posted June 9, 2019 Author Share Posted June 9, 2019 JMO413, thanks for the response. I too have a broken stud on my exhaust, but due to the angle I feel the head is gonna have to be pulled to drill/tap a new one. I hope changing your exhaust fixes your tap. I'm interested to know how it goes. Link to comment Share on other sites More sharing options...
JMO413 Posted June 9, 2019 Share Posted June 9, 2019 I'm going to try to weld to the broken one I have. It's the back one so hopefully I can get it with the head on. Link to comment Share on other sites More sharing options...
JMO413 Posted June 16, 2019 Share Posted June 16, 2019 Mine is definitely quieter with the new manifold. Still have some valve train nose but the heavy tick is gone. I believe it was either the cracked manifold and or the broken stud. You can see where it was leaking in the gasket. It was definitely a problem. The new timing chain may have helped a little also. Link to comment Share on other sites More sharing options...
MT Jeep Posted June 17, 2019 Author Share Posted June 17, 2019 Congrats! JMO413, you don't happen to have a video clip of your truck idling and ticking before you did the manifold fix do you? If they sound the same to my ear I'm gonna go ahead and repair mine as well. Link to comment Share on other sites More sharing options...
JMO413 Posted June 17, 2019 Share Posted June 17, 2019 Here is mine Link to comment Share on other sites More sharing options...
JMO413 Posted June 17, 2019 Share Posted June 17, 2019 On 6/8/2019 at 7:48 PM, MT Jeep said: JMO413, thanks for the response. I too have a broken stud on my exhaust, but due to the angle I feel the head is gonna have to be pulled to drill/tap a new one. I hope changing your exhaust fixes your tap. I'm interested to know how it goes. My rear stud was what was broken I'm guessing yours is too the same. I justed welded a nut to it. Came right out. Link to comment Share on other sites More sharing options...
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