Another piston slap/lifter question

I've spent the better part of an hour combing over the various threads concerning piston slap and lifter noise, but I'd just like to post my situation and see what you all think:

93 Sport, 4.0L, I've owned it since 2002, when it had ~150K. Today it has ~192K. It has had the typical tapping noise since I've gotten it. I've done nothing special to the car aside from the regular tune up and oil change, and replacing things like the radiator, starter, battery, thermostat, but my growing curiosity towards cars and my desire to keep this thing running as long as possible has made me wonder if there is something I could do to stop this.

The tapping increases in frequency as engine RPM increases. I cannot notice the noise at typical highway RPM (~2000 for me), but that may be just because of wind noise, etc.

The tapping is apparent at a cold idle, and while it seems to go away somewhat as the engine warms up, it never goes completely away. I will be doing the poor-man's stethoscope test as soon as I get my hands on a piece of hose. Am I correct in that if I remove the oil filler cap and take a listen there, if the noise increases that this is a symptom of a lifter issue and not just normal piston slap?

The way I see it, I have a couple of options as to what to do once I pinpoint the noise (assuming it is a lifter issue for the time being):

1) Do nothing. Its worked this way for the 40K I've been running the Jeep, more than likely some time before I owned it, and it'll continue running as long as I change the oil regularly.

2) Try adding something like MMO and see if that quiets the lifter(s). My concern is this: at "best" it quiets the lifter and my Jeep no longer sounds like a diesel. at "medium", it does nothing and I still have the sound. at "worst", it cleans up the inside of the engine, producing god knows how many leaks in gaskets all over the place.

If you were in my position, what would you do?

Piston slap and lifter noise sound different. Can you take a video of the noise and post a link?

Piston slap noise will change a little or a lot when you remove spark from the affected cylinder at idle, lifter noise won't change.

You bet, I was thinking of doing the same. I'll take a video of the engine noise at a cold start, and then a video of the engine noise at a hot idle. I'll post that at some point later today or tomorrow.

You can use a long bladed screwdriver as a stethoscope to help isolate the location of the tapping. Put the tip to various places around the valve cover and your ear to the handle. You'll be amazed at how much it amplifies the noise. Or, you can buy a mechanics stethoscope.

Be careful where you put the blade.

I just bought a mechanics stethoscope on eBay, when that arrives it should help narrow down the problem. In the meantime, I'll post those videos soon.

JJacobs said:

Piston slap noise will change a little or a lot when you remove spark from the affected cylinder at idle, lifter noise won't change.

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That is absolutely true. Just pull the wire off each plug (making sure you use long reach, INSULATED handle pliers). Removing the boom keeps the piston from cocking in the cylinder. The only real repair for lifter noise is to replace the lifters. All those additives are just temporary snake oil fixes if you ask me.

Cracked exhaust manifolds are also really good at making internal engine-like noises that change with temperature.

Alright here are some videos.

This first one is a cold start. What was interesting to me is that I couldn't start really hearing the tapping until ~1min after it started up.

http://www.youtube.com/watch?v=3XgmZ5M3S8M

This next one is after it got up to temperature:

http://www.youtube.com/watch?v=oJ1GafLPOMM

One thing, unrelated to the tapping, how does my oil pressure look to you? It seems high, especially that hot idle...

JJacobs said:

Cracked exhaust manifolds are also really good at making internal engine-like noises that change with temperature.

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that is what i'm thinking... piston slap can be kinda intermittent.. lifters tend to be more constant and exhaust leaks tend to change as the pipe heats up and expands.

Adding MMO will not cause any oil seal leaks of any kind. Adding synthetic oil if you are not already using synthetic oil can cause sudden oil seal leaks in older engines like yours.

Nothing dangerous about adding MMO.

I got rid of my lifter noise pretty much permanently over time with 1 pint of MMO plus one quart of Lucas oil additive (NON-synthetic) during each oil change for about 15,000 miles. Those additives substantially quited the cold engine start up noise and helped kill the noise faster as the engine heated up, and helped clean the dried up varnish out, slowly over time. The noise would be almost gone with the addtives and a warm (160 F) engine. Now the noise only shows up for a few seconds on a very cold start morning (like under 40 F), and then quickly goes away. I don't notice any noise at all now on normal weather days even at start up.

The lifter noise (IMNSHO) is caused by dried up varnish in the lifter area that makes the lifter stick causing the noise.

Thanks for the info, Ecomike. I'm glad to hear that they won't create any problems. The next time I change my oil (coming up in ~1K miles), I'll add the MMO and Lucas.

Regarding the videos I posted, does anyone have any thoughts? Am I just looking for trouble, or does it actually sound like something?

MJCfromCT said:

Regarding the videos I posted, does anyone have any thoughts? Am I just looking for trouble, or does it actually sound like something?

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Ecomike's idea sounds the most likely. Lucas is really, really good. I have had so much success with Z-Max in both the oil and gas, its really not funny. It is the best additve i have ever used. I treated my 92 XJ with it 4 years ago, I still haven't have any major carbon build up. No joke, the stuff is worth the 30$.

MJCfromCT said:

Thanks for the info, Ecomike. I'm glad to hear that they won't create any problems. The next time I change my oil (coming up in ~1K miles), I'll add the MMO and Lucas.

Regarding the videos I posted, does anyone have any thoughts? Am I just looking for trouble, or does it actually sound like something?

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I have the EXACT same noise at winter cold startup and as the engine warms it becomes much quieter and a more marbely, if that's a word, noise. Anyway, I also assume that its sticky lifters and have started adding a quart of MMO with 5 quarts 10w30 every oil change. My oil pressure at startup is 55# and 25-30# at "hot oil" idle even with the quart of MMO. As for your oil pressure, just because your engine is at temp doesn't mean that oil has also reached that temp. I have done an oil change after letting my cold engine reach temp only to find that the oil is still cold or luke warm. My guess is that if you can drive it for about 10-15 miles on the highway and its still reading around 60#, then I might be a little concerned just because that seems really high for oil that's probably scalding hot. However, if it's 40# or lower, I wouldn't be concerned. Just my opinion.

smokeman said:

As for your oil pressure, just because your engine is at temp doesn't mean that oil has also reached that temp. I have done an oil change after letting my cold engine reach temp only to find that the oil is still cold or luke warm. My guess is that if you can drive it for about 10-15 miles on the highway and its still reading around 60#, then I might be a little concerned just because that seems really high for oil that's probably scalding hot. However, if it's 40# or lower, I wouldn't be concerned. Just my opinion.

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That's a good point. I had only driven it around for ~10 mins before the engine temp got to its normal operating range, I didn't even think about the fact that the oil itself will take longer to heat up.

MJCfromCT said:

Thanks for the info, Ecomike. I'm glad to hear that they won't create any problems. The next time I change my oil (coming up in ~1K miles), I'll add the MMO and Lucas.

Regarding the videos I posted, does anyone have any thoughts? Am I just looking for trouble, or does it actually sound like something?

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Sounds mostly like piston slap to me, but I'd listen carefully for manifold leaks too. Also make sure it isn't the water pump. If you have some piston slap you can be lulled into ignoring the sound of a bad water pump because it's not all that different.

Thanks for the reply, Matthew Currie. I will definitlely be checking out the water pump, as my Jeep has been known to "howl" when it gets very cold. It hasn't done it in the past few weeks, but its done it a good 4 or 5 times this winter, and probably 4 or 5 times last winter.

While this isn't a video of my Jeep, its the exact same noise, take a gander and see if this sounds like a dying water pump?

http://www.youtube.com/watch?v=N0w8x4Zcae4

It's hard to say with those videos. Definitely got a better listen in the cold start one. That sounds like a pretty metallic noise and definitely not exhaust leaks. The second video was too short to really say.

I'd try a couple things. First go out to a flat road and run about 35 mph in high gear. Slightly modulate the throttle and see if you can get the noise to come and go. This checks the rod bearings.
Then get some insulated pliers and remove the plug wires with it idling, one at a time, and see if any cylinder changes the noise.

Yeah, I wanted the second video to be longer, but my camera ran out of space . The next time I get it to a hot idle I'll take another video.

I will try what you suggest too. One thing I have noticed is that when I'm in a low gear and begin to accelerate, I can hear a "psst psst psst" sound that goes with the RPM of the engine. It almost sounds like what you'd hear if you shot a quick burst of air from an air compressor...I'm not sure if this is related, though.

I don't mean to hijack the thread, but I have also been reading over the engine noise threads. Mine is quiet for the first minute or so of cold startup, then knocks like a girlscout on the last day of cookie sales. Does not increase with throttle. New exhasut manifold installed. Sounds rather loud and worries me, I was told that it sounded like it's coming from the bottom end. Any advice? Please PM me so this doesn't become a complete hijack to the OP.
Thanks.

MJCfromCT said:

Yeah, I wanted the second video to be longer, but my camera ran out of space . The next time I get it to a hot idle I'll take another video.

I will try what you suggest too. One thing I have noticed is that when I'm in a low gear and begin to accelerate, I can hear a "psst psst psst" sound that goes with the RPM of the engine. It almost sounds like what you'd hear if you shot a quick burst of air from an air compressor...I'm not sure if this is related, though.

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"psst psst psst", is a vacuum or exhaust leak. Check the throttle body rubber plug-vacuum hose connection, bottom side, passenger side of the throttle body. The little plastic tube connects to the MAP sensor on the firewall. When it gets loose at the throttle body it makes that sound too. Also check the intake and exhaust manifold for leaks, and the exhaust pipe connection to the manifold.