Valve Train Noise...

[Squatch]

Okay, so I spent the weekend doing maintenance and repairs on four different vehicles this weekend, one of them being my wife's '96 XJ with a 4.0 in it. Being that it and our little Mazda Protégé both use 10W-30, and I had the full synthetic Mobil -1 on hand, that's what I used in the Jeep. When I went to park the rig after I was done, I could hear valve train clatter that I have never noticed before. I immediately double-checked the oil level (full), and confirmed I had used the 10W-30 oil, and not something else by mistake. I had my wife come out and listen to it with the hood open. I explained what I was hearing, and she asked "The noise that makes it sound like a diesel?" Perfect description! It clatters like a diesel at about 1,200-1,800 rpms. After that, fan and exhaust noise drown out anything else I can easily identify. The clatter is not wicked-loud, or anything...just sounds "sloppy", like everything on the top end has a bit too much clearance.

The rig has 170,500 miles on it. When I replaced the valve cover gasket some time ago, I was impressed with how clean the valve train was (no sludge or such). It is not a knocking sound, nor is it a lifter tick. I've only ever had one vehicle with piston slap, so I'm not real experienced with that issue, but I can say it does not sound like what my other rig sounded like, so I don't believe it's piston slap. The oil pressure gauge has never been accurate (will read 40 psi, then jump up to pegged-out, then back down to 40 psi, etc). I replaced the sending unit once, but it made no difference. I'm thinking I will install an aftermarket system so I can at least see what we're really running.

So, this is either a new issue that has just arisen, or it is something that started happening a while ago, and my wife never noticed it (her hearing isn't stellar). I don't drive the rig, so I just don't know if this started some time ago, or not. If it is a new issue, could this be the result of using a full synthetic oil instead of the conventional dino oil I've always used? I've read some things online saying it's possible, and an equal number of folks saying it's not. All I know is this is the first time I've used synthetic in it. As it stands now, I'm going to have my wife drive the Mazda this week, and I'm going to change the oil again next week to conventional. In the meantime, I would very much like to hear from you folks on your thoughts on the issue.
Thanks in advance for your assistance.
Regards, Squatch

 

[Mike_H]

I've noticed mine making a similar clatter. It goes away once warm. I think it's piston slap, I had one of the infamous Chevy 5.3l engines that did the same.

 

[jeep_boss]

I had that same problem, my shit sounded like a Cummins when it was cold. It went away after I replaced my exhaust manifold.

If you're sure that it's not the exhaust manifold, just do the poor man's stethoscope trick with a very long screwdriver to your ear and put the tip of it against the sections of the motor that are suspect to isolate the sound.

 

[Squatch]

29 views, and no comments? Is this an untouchable issue?

I've noticed mine making a similar clatter. It goes away once warm. I think it's piston slap, I had one of the infamous Chevy 5.3l engines that did the same.

I read somewhere that piston slap was a problem on the earlier 4.0, but not the later '96 and up versions. Can't remember what the difference was, so I'll have to go back and try to find that info. It does seem to be coming from the upper end, as best as I can tell. Going to delve into it further this weekend. Thanks for responding, Chief!

 

[Squatch]

I had that same problem, my shit sounded like a Cummins when it was cold. It went away after I replaced my exhaust manifold.

If you're sure that it's not the exhaust manifold, just do the poor man's stethoscope trick with a very long screwdriver to your ear and put the tip of it against the sections of the motor that are suspect to isolate the sound.

I'm fairly certain it's in the valve train. I used a rich man's version of a stethoscope. It's called a "stethoscope". LOL So, yeah, with the stethoscope, it does seem to be coming from the rocker assemblies, as best I can tell. I'm going to start with switching back over to conventional oil this weekend, and see if that makes any difference. If not, I'll likely pull the valve cover and check stuff out. I'm not against replacing the pushrods, rockers and bridges if it helps quiet it down. Less enthused about having to pull the head to replace lifters, but if I have to, I have to. My wife adores this little 2-door XJ, so I'll do what it takes to keep it around.

One thing you and @Ranger_b0b both mentioned is that both of yours were noisy when cold. Our XJ had just been driven quite a few miles before I did the oil change, so the engine was still warm, though the new oil was not. Not sure if it matters, but just thought I'd mention it. Thanks for the input, buddy!

 

[pagrey]

I might check the timing chain, it's pretty easy to check without taking anything apart and can cause strange noises when it gets loose that seem to come from block or valve train like you describe.

 

[Squatch]

I might check the timing chain, it's pretty easy to check without taking anything apart and can cause strange noises when it gets loose that seem to come from block or valve train like you describe.

I had checked the timing chain about 10,000 miles ago, and there was no discernible play in it. Also, for what it's worth, the 4.0 rarely suffers from a sloppy t-chain, based primarily on the fact the chain is so dang short. I've dealt with chains on different engines where they'd get so sloppy, you could almost pull them off without removing the gears (Did that on a Ford 302, once. Can't believe the guy was driving it!). But the 4.0 I6 just doesn't seem to suffer from that affliction, from what I can tell. But you're right, it's worth checking again, and I shall. Thanks for the tip!

 

[pagrey]

Also, for what it's worth, the 4.0 rarely suffers from a sloppy t-chain, based primarily on the fact the chain is so dang short.

I totally agree, mine failed early so I think every 4.0 noise is timing chain related. They are probably going to engrave it on my tombstone "I told you it was the timing chain"

 

[Squatch]

I totally agree, mine failed early so I think every 4.0 noise is timing chain related. They are probably going to engrave it on my tombstone "I told you it was the timing chain"

Your t-chain failed early on your 4.0? How many miles were on it, if you don't mind my asking? Also, what year was it? I find this intriguing, as it goes against everything I'd read when looking into these motors years ago. Not saying it isn't so, my friend, just saying it would appear to be fairly uncommon.

 

[pagrey]

just saying it would appear to be fairly uncommon.

I have heard this too, part of the reason it took me so long to find the noise. All the experts say that the chain will last the life of the engine and I think that is the rule. Here is the play in mine at 120K if the video link works. It knocked like a piston skirt or connecting rod since about 100K, loud enough a fellow Jeeper thought I was in for a rebuild soon. I couldn't hear any chain slap, it was all the cam bouncing around in the block. It was really obvious with a breaker bar on the crank. I'd just check it and forget it, super rare but it does happen.

 

[Squatch]

I have heard this too, part of the reason it took me so long to find the noise. All the experts say that the chain will last the life of the engine and I think that is the rule. Here is the play in mine at 120K if the video link works. It knocked like a piston skirt or connecting rod since about 100K, loud enough a fellow Jeeper thought I was in for a rebuild soon. I couldn't hear any chain slap, it was all the cam bouncing around in the block. It was really obvious with a breaker bar on the crank. I'd just check it and forget it, super rare but it does happen.

Alright, then. I will give that possibility more consideration after having seen that video. I greatly appreciate the input, @pagrey. Many thanks!

 

[Squatch]

Changed the oil back to conventional 10W-30 this evening, and it made no difference. Being that it's not an obnoxiously loud noise/clatter, I'm just going to let it ride for the time being. I'll make a point to check to see if it's getting worse on a weekly basis, as I can't truly expect my little bride to hear it. It might be nothing more than the "car guy curse". You know the routine. Car guys don't just hear an engine running. They hear the engine. Lifter ticks, exhaust leaks, slight misfires, vacuum leaks, etc. etc. Sometimes what we hear is normal, and we still tend to break down the individual sounds of a good running engine. That might be what I'm doing. (shrug)
Thanks for the input, guys. Not a terribly exciting subject, I know, but I do appreciate your assistance.

 

[jeep_boss]

Changed the oil back to conventional 10W-30 this evening, and it made no difference. Being that it's not an obnoxiously loud noise/clatter, I'm just going to let it ride for the time being. I'll make a point to check to see if it's getting worse on a weekly basis, as I can't truly expect my little bride to hear it. It might be nothing more than the "car guy curse". You know the routine. Car guys don't just hear an engine running. They hear the engine. Lifter ticks, exhaust leaks, slight misfires, vacuum leaks, etc. etc. Sometimes what we hear is normal, and we still tend to break down the individual sounds of a good running engine. That might be what I'm doing. (shrug)
Thanks for the input, guys. Not a terribly exciting subject, I know, but I do appreciate your assistance.

For better or worse, one of the things that I miss about >=1997 Toyotas is troubleshooting mechanical issues. They are very good at telling you precisely what the problem is.

 

[Squatch]

For better or worse, one of the things that I miss about >=1997 Toyotas is troubleshooting mechanical issues. They are very good at telling you precisely what the problem is.

Wait a minute. You had a Toyota that had problems? LOL
With the XJ, the hang up is that I'm not entirely sure it even is a problem. I'll look into it a little deeper this summer, unless it indicates to me it needs attention sooner than that. I'll check the timing chain again for slop, as suggested in an earlier post, and replace, if needed. Will likely replace valve train assembly, as well. New rockers, bridges and pushrods are only around a hundred bucks, so why not. The originals will have around 180,000 miles on them by then, so quality new ones can't hurt.

 

[Brandon Casey0]

I have an 03 tj 4.0 with 130k miles and it makes an UNGODLY valvetrain noise. Its a loud TICK TICK TICK when driving but at idle its very quiet. Im afraid like a lifter collapsed or something

 

[Squatch]

I have an 03 tj 4.0 with 130k miles and it makes an UNGODLY valvetrain noise. Its a loud TICK TICK TICK when driving but at idle its very quiet. Im afraid like a lifter collapsed or something

Quite often, an exhaust leak will sound very similar to a collapsed lifter. The fact that there is no noise (tick) at idle leads me to think it's not a lifter, in your case. Every collapsed lifter that I've ever dealt with could be heard, to some extent, at idle. Then again, it's hard to diagnose it from 8 hours north of you. By the way, my wife is from Medford. Almost her entire family is still in that area. Beautiful country, for sure.

 

[Brandon Casey0]

Quite often, an exhaust leak will sound very similar to a collapsed lifter. The fact that there is no noise (tick) at idle leads me to think it's not a lifter, in your case. Every collapsed lifter that I've ever dealt with could be heard, to some extent, at idle. Then again, it's hard to diagnose it from 8 hours north of you. By the way, my wife is from Medford. Almost her entire family is still in that area. Beautiful country, for sure.

Is there a way to check without replacing it? I dont want to spend money to find out it was pointless lol.

 

[Squatch]

Is there a way to check without replacing it? I dont want to spend money to find out it was pointless lol.

Check for a collapsed lifter, or an exhaust leak? I'm going to assume you mean lifter, and go with that. I'd start with getting the hood up, and listening to the engine while getting the rpms up enough to get the "tick" going. If it's obvious that it's coming from under the valve cover, then you've at least narrowed it down to likely being a valve train issue. If you cannot tell for certain, you can try using a mechanic's stethoscope placed in different areas along the valve cover to find where it's coming from. No stethoscope? You can use a long screwdriver with the handle placed against your ear, and the blade end against the valve cover. Be careful while doing this, obviously. The sound will transmit, and give you a better idea where it's coming from. After that, it will kind of depend on how comfortable you are around engines. Do you tinker around with them much? I mean no disrespect, I just don't know how involved you want to get. It's not difficult, but to someone who hasn't worked around vehicles much, it could be a little intimidating, even though it's still just the testing/research phase.

 

[Brandon Casey0]

Check for a collapsed lifter, or an exhaust leak? I'm going to assume you mean lifter, and go with that. I'd start with getting the hood up, and listening to the engine while getting the rpms up enough to get the "tick" going. If it's obvious that it's coming from under the valve cover, then you've at least narrowed it down to likely being a valve train issue. If you cannot tell for certain, you can try using a mechanic's stethoscope placed in different areas along the valve cover to find where it's coming from. No stethoscope? You can use a long screwdriver with the handle placed against your ear, and the blade end against the valve cover. Be careful while doing this, obviously. The sound will transmit, and give you a better idea where it's coming from. After that, it will kind of depend on how comfortable you are around engines. Do you tinker around with them much? I mean no disrespect, I just don't know how involved you want to get. It's not difficult, but to someone who hasn't worked around vehicles much, it could be a little intimidating, even though it's still just the testing/research phase.

I'm 21 and I'm a lube tech for nissan right now, but I used to build engines for a local shop in town, I simply have no experience in diagnosing sounds. I actually have an update as well. On my way to work today instead of lifter tap, I got a metal on metal shieking sound. But as soon as I let off it went away. I probably need an engine at this point and its only got 137k miles.

 

[Squatch]

I'm 21 and I'm a lube tech for nissan right now, but I used to build engines for a local shop in town, I simply have no experience in diagnosing sounds. I actually have an update as well. On my way to work today instead of lifter tap, I got a metal on metal shieking sound. But as soon as I let off it went away. I probably need an engine at this point and its only got 137k miles.

I don't typically recommend this, but you might want to get it in to a shop that you feel you can trust and have them take a listen to it. Have them explain their diagnosis in detail, and see if it makes sense to you. Research their explanation online, and see if you can find information that supports their diagnosis. I would take this route before jumping into the cost of a new engine. I bought an '85 Chrysler New Yorker once that had a "blown engine". Opened up the hood, and their was oil sprayed everywhere. Paid $50 for it, put in a new PCV valve, which fixed the problem, and sold it for $600. Point is, your issue may actually be very minor.