Is that knocking I hear, or just "Jeep noises"?

[brucecooner]

I'm one of those unfortunate guys who can apparently hear every mechanical piece in a car rubbing against all of its neighboring pieces.

 

Sometimes this works in my favor, as when I had to almost physically shove an engine tech's head under the hood into just the right place so that he FINALLY heard an out of place ticking noise he had sworn he'd listened for (yeah, I'm sure you did) and couldn't hear, that turned out to be due to inaccurate head bolt torque.

 

But most of the time having this sort of hearing without being a moderately experienced mechanic is MADDENING.

I'll hear what I think is a new noise, at which point I wonder if the noise is really new, or if I've just failed to notice it before.

My usual tactic is to turn up the radio (well, before the radio went kaput in the Ranger anyway) and try to think about my destination.

 

So it doesn't help that in the Jeep I'm behind the wheel of a new-to-me-but-pretty-old vehicle, so I'm not sure if my Jeep is making Jeep noises, or is knocking, or the pistons are slapping around, or ???

 

These knockings seem to have gotten louder recently, but I haven't been driving it frequently so maybe I'd just forgotten them? Or was I inadvertently ignoring them?

 

Anyway, recently I noticed what seems like a loud knock when I opened the driver's side door with it running.

After the recent oil change, it was still audible, so I got down low and took a few seconds of video...

 

 

 

 

 

This led me to listen up top.  The valves sure are a-ticking, hopefully that's a normal amount of noise, but I do still kind of hear that knocking below the general cacophony.

 

 

 

Not that I really expect a super accurate diagnosis of anything, but my general question here is, are the 4.0's supposed to make that much noise?

 

And I've got to say, it drives just fine.  I can tell it has more power than the Ranger (3.0 Vulcan). 

I mean, it's not quick off the line, and I definitely don't push it, but it is pretty bullheaded and straightforward about the whole acceleration business.

 

 

 

 

[cruiser54]

Sounds normal to me. 

Does your Jeep have a tachometer? How high do you ever rev it? 

[AZJeff]

It sounds fairly normal to me, but it's a bit hard to tell for sure, because I hear several different rhythmic noises in your two video clips.

 

You can help pinpoint the source of the noise by using a mechanics stethoscopic and probing around various parts of the engine.  If you lack the stethoscope, then a section of wooden dowel rod, or a long screwdriver, can substitute.;

 

The 4.0 is not a quiet engine, but most of it's sounds should be steady and rhythmic.  Trying to make it as quiet as some newer engines is pretty much impossible.

[Minuit]

I don't hear anything unnerving here. My truck(s) make all of the same noises. Maybe not as loud, but they're all there.

 

 

[JMO413]

Mine makes all those noises also.

[brucecooner]

13 hours ago, cruiser54 said:

Sounds normal to me. 

Does your Jeep have a tachometer? How high do you ever rev it? 

Yep, has a tach.  I never run it over 2 grand, but for now I just take it on pleasure cruises on area backroads.

I might touch 50mph briefly down on Route 85 before I turn off. I didn't buy it to go fast.  :)

It did the high idle thing briefly a while back, and it was sitting just over 2 grand if I remember. 

But I didn't drive it far before I had a brief tussle with the brake, and the leaking booster (which is a whole other thing that probably warrants a thread) somehow corrected the high idle.

 

 

 

10 hours ago, AZJeff said:

t sounds fairly normal to me, but it's a bit hard to tell for sure, because I hear several different rhythmic noises in your two video clips.

 

You can help pinpoint the source of the noise by using a mechanics stethoscopic and probing around various parts of the engine.  If you lack the stethoscope, then a section of wooden dowel rod, or a long screwdriver, can substitute.;

I've seen a mechanic investigate a whiny power steering pump with a screwdriver once, had totally forgotten about that trick.

And yeah sorry about the use of video here,  I admit it's not a great tool.

 

This vehicle definitely makes a bit more racket than the old Ranger, which given the provenance of the powertrain isn't surprising.

I actually kind of like the various normal sounding rackets it makes when I drive it. 

Well, except for that clunk from the frontend when I take off with the wheels turned. 

I've jacked up the front and tugged on all the suspension bits I could reach.  Despite the thirty plus year old crusty brackets everywhere, it's all surprisingly tight.

Now that I think of it, the Ranger did the "clunk when turning thing" too, and it was the tie rod end link bushings, I hadn't even thought to check for those on the Jeep.

 

But if nobody here is saying "OMG your X is going out", I'll just turn up the radio and think about my destination.

 

[cruiser54]

Why are you lugging it around? 

Start shifting at 3,000 RPM. Or higher. 

That engine was designed to run up to 4800 RPM. 

[Classy Comanche]

Yeah I'm cursed with a mechanics ear too. Aggravating but helpful. Any small pop, creak or noise I hear I immediately investigate. Here I showed to videos. Also kinda wondering if it sounds okay, apologies for the loud  muffler, it's literally rusted in half about where the bed is. But that ticking. That the lifters? Also this morning I cranked it and it did I high Rev for about 2 seconds then settled down. It was in the upper 60's today. It rarely does it except on chillier weather. Anyone else have that occurrence or is this something I eventually need to look into, with the every once on a blue moon high crank rev. Like I said. Rarely does it and does it in comfortable or chilly weather. 

[Salvagedcircuit]

That does sound normal to me. I would do these two cruiser54 tips:

Cruiser tip #11 (Throttle Body and IAC Cleaning)

http://cruiser54.com/?p=60

 

Cruiser tip #4 (Renix ICU/Coil Contact Refreshing)

http://cruiser54.com/?p=41

 

My Idler Air control Valve and throttle body cavity were completely coated in carbon. The main 3 pin plug on my ignition coil needed replacement after a very bodged together twisted wire repair from the PO. No solder, crimp, wirenut... just twisted wire wrapped in electrical tape.

My 4.0 is a lot more stable at idle after these fixes.

 

[Classy Comanche]

Ah! Okay. I just didn't know. It's just a good and bad thing having a mechanic ear. Some days I can hear the coolant and fluid rushing through my engine and it drives me crazy. I just didn't know if these little 4.0's are moderately noisy. I know my lifters are loud. As I give it gas it does speed up then eventually goes away. But yeah. I'll look in that direction. It runs good. Just didn't know if it sounded okay despite it being a noisy little engine. My '03 Monte Carlo SS is 2 times quieter than this, and it's a bigger V6

[brucecooner]

22 hours ago, cruiser54 said:

Why are you lugging it around? 

Start shifting at 3,000 RPM. Or higher. 

That engine was designed to run up to 4800 RPM. 

I just drive like an old man.  Always have. 

Also being it's a thirty year old truck, and new to me, I'm afraid of it flying apart.

 

I will say too, I've been going by the shift indicator light, and it lights off a little shy of 2000, at maybe 1750-1800. 

Which honestly sounds a little low to be shifting. My ears say it wants to go a bit higher before the upshift. 

 

 

[brucecooner]

3 hours ago, Classy Comanche said:

Yeah I'm cursed with a mechanics ear too. Aggravating but helpful. Any small pop, creak or noise I hear I immediately investigate. Here I showed to videos. Also kinda wondering if it sounds okay, apologies for the loud  muffler, it's literally rusted in half about where the bed is. But that ticking. That the lifters? Also this morning I cranked it and it did I high Rev for about 2 seconds then settled down. It was in the upper 60's today. It rarely does it except on chillier weather. Anyone else have that occurrence or is this something I eventually need to look into, with the every once on a blue moon high crank rev. Like I said. Rarely does it and does it in comfortable or chilly weather. 

 

That actually sounds quieter than mine even.

I think if you have the mechanic's ear then lifters are just like nails on a chalkboard, no matter the engine.

 

 

[Classy Comanche]

Yeah. It's just loud clicking outside the vehicle. Inside you can just hear the muffler and hum of the engine. I do get my oil changed every 3000 miles. But I actually do it at 2700 since the motors are old. And trying to do preventive maintenance and help it. I've actually never really heard another straight 6 4.0 before other than mine. So I haven't been really able to compare except to my car. Which is about 20 years newer and super quiet. But I'm glad everything sounds good! It's just that muffler. I need it swapped out so it doesn't sound like I straight piped it on purpose still the same factor OEM muffler off the assembly line!

[cruiser54]

Bruce, your fears are unfounded. You're lugging the living crap out of that motor.

The shift indicator light was ONLY THERE TO PASS THE DRIVING EMISSIONS TEST!

[Classy Comanche]

Out of curiosity what does your guy's 4.0's sound like? Probably a odd question but I didn't know if your guy's is as loud or quieter than mine. Never heard another one before like really listening

[Minuit]

 

Almost 193k on this one. Also apparently I zoomed right in on my nasty valve cover for half of it so you can see in glorious detail that I haven't cleaned my engine in over a year

[Classy Comanche]

Ah! So they are noisy in general. Yep that I was curious about. Cool deal! Thank you! I wasn't sure if I had something going on and if mine happened to be loud for no reason. It's nice to know all of these tick and make racket just simply running and working. Family also pointed out it was loud compared to engines today. So that made me super curious. As always you fellas are a tremendous help!

[brucecooner]

7 hours ago, Minuit said:

 

Almost 193k on this one. Also apparently I zoomed right in on my nasty valve cover for half of it so you can see in glorious detail that I haven't cleaned my engine in over a year

I think I can hear the exact same noise in your video that led me to record mine, particularly on the bottom side.

 

So wow, they actually are supposed to make all those clattering noises.  

My dad a had an old Massey Ferguson that I think was quieter than that.

 

I won't be catching any pedestrians by surprise but as long as it's healthy it can make whatever music it wants.

 

 

 

 

 

 

 

 

[cruiser54]

Most of what you hear is piston slap. 

They make that sound from when they're born until they die. There was a lawsuit about it and Jeep won. 

[87MJJeep]

4 hours ago, cruiser54 said:

Most of what you hear is piston slap. 

They make that sound from when they're born until they die. There was a lawsuit about it and Jeep won. 

My 93 ZJ 4.0 slaps a LOT more than my '87 MJ.  My '87's slap sounds more like "knocking" than "slapping" if that makes sense.  Even my '04 4.7L HO also has some slap.  

 

But none slap like my my 2001 LS1 Trans Am.  At an event at the Corvette museum in Bowling Green back in the day, one of the GM guest speakers listened to it.  He was some really high up Quality guy.  He said, "Yes, you have piston slap.  And loose wrist pins.  And a noisy valvetrain, too.  Just keep Mobile 1 in it, and you'll be fine."  It's been beat on in 12 road course events since 2002.  It's fine.  

 

Noisy engines have character.   

[cruiser54]

Piston slap became a bigger issue when the HO was introduced. 

[brucecooner]

17 hours ago, cruiser54 said:

Most of what you hear is piston slap. 

They make that sound from when they're born until they die. There was a lawsuit about it and Jeep won. 

 

I've seen guys in a lot of threads around the internet comment that they ran a 4.0 for hundreds of thousands of miles making a steady slap without issue, but I was not aware the U.S. Judicial System had ruled it to be a normal sound.

[Minuit]

My truck has sounded exactly like that for the 49,000 miles I've put on it, and probably for the 144,000 miles that were on it before. It's never been apart further than it takes to replace the timing chain and rear main seal, and it's been well maintained since new. When I first got it I was also very concerned with the noise. It's just a Jeep thing.

 

The later NVH blocks with the bearing girdle are a little better, but the piston slap is still there. The later 4.0s also have a tendency to break piston skirts.

[Minuit]

If you guys want to hear some REAL noise, I could always go record a clip of my '89 with a severely blown exhaust gasket on multiple cylinders, a badly cracked exhaust manifold, next to no oil pressure, and at least one stuck lifter

[brucecooner]

On 8/20/2022 at 6:06 AM, Minuit said:

If you guys want to hear some REAL noise, I could always go record a clip of my '89 with a severely blown exhaust gasket on multiple cylinders, a badly cracked exhaust manifold, next to no oil pressure, and at least one stuck lifter

 

Now knowing how they sound normally, I can't imagine how you'd be able to hear all that other stuff.