Intermittent metallic flutter/rattle at low idle

[pwkunde]

1998 Explorer XLT. V6 SOHC.

I've read many previous threads regarding noises like this, but none of them seem to match what I'm hearing. It's a metal on metal vibration-induced rattle. It's erratic, which I'm thinking rules out the timing chain. My mechanic has also listened to the engine and doesn't think it has anything to do with the timing chain. He thought it might be a heat shield and spot welded a suspect area. So far as I can tell, it's not associated with heat shields around the cat (the sound isn't that far back). I pulled the flexible rubber cover/panel on the inside of the wheel well and localized the sound to the mid- to lower- right side of the engine, near the exhaust manifold and engine mount. Are there any internal one-way valves that might be fluttering at idle? Are there any other heat shields I don't know about? Could this be anything else? Thanks.

 

[pwkunde]

I had a mechanic look at my Explorer today. He couldn't find a specific source, but said that it's probably something that's loose and rattling down by/in the cat (not a heat shield, possibly something inside), like a one-way valve. The sound just bounces around, making it hard to locate. Since there's nothing wrong with the cat or the exhaust system, I'm not going to fix it. I'll just deal with it and have people assume that Will Ferrell is underneath my car playing cowbell. Hopefully this post will help someone who hears something similar.

 

[happyjack87]

this does seem to be similar to what im hearing. does yours have the same sound during shifts?

 

[gijoecam]

There's no valve in the exhaust... It could be the catalyst itself rattling, or it could very well be the heat shield that clips to the transmission pan lip to block the heat from teh cats. Every winter at some point, I hit a pile of snow and slush just the right way, and it knocks the heat shield off the side of the transmission. Then, the shield just sits there and rattles on the cats at idle. I usually find it during my first spring oil change. (like I did Sunday)

-Joe

 

[pwkunde]

I've never seen the inside of the cat, so I have no idea as to what can go wrong or rattle. I plan on changing the oil next week, so hopefully I'll find something loose when I get under there. It would be nice if it was an easy fix.

I only seem to hear it when I'm idling, or after I've let off the gas. Either it stops during acceleration, or the engine makes too much noise and I'm not able to hear it. After having a mechanic look at it twice, and looking for myself, I don't know what to think. I'm just tired of hearing it.

 

[pwkunde]

Oh, and Happyjack, I forgot to mention that the sound doesn't seem to intensify in volume or increase in frequency when I'm driving or at different speeds. It's always the same sound... never changing... haunting me.

 

[FL G8R]

1998 Explorer XLT. V6 SOHC.

I've read many previous threads regarding noises like this, but none of them seem to match what I'm hearing. It's a metal on metal vibration-induced rattle. It's erratic, which I'm thinking rules out the timing chain. My mechanic has also listened to the engine and doesn't think it has anything to do with the timing chain. He thought it might be a heat shield and spot welded a suspect area. So far as I can tell, it's not associated with heat shields around the cat (the sound isn't that far back). I pulled the flexible rubber cover/panel on the inside of the wheel well and localized the sound to the mid- to lower- right side of the engine, near the exhaust manifold and engine mount. Are there any internal one-way valves that might be fluttering at idle? Are there any other heat shields I don't know about? Could this be anything else? Thanks.

Hey all-

I came across this forum because I was trying to track down the source of a noise in my '98 V8 Explorer--- and this person's description sums it up perfectly. I have a metallic fluttering noise that appears when I de-accelerate or when I am in idle. It is intermittent and I have been trying to figure out what the heck it is for the last year. A few different shops couldn't figure it out, but I am almost positive it has to do with the exhaust system (as the poster stated above). I try to take good care of my truck and have not had any huge problems with it, but this noise drives me nuts. Any help/advice you all are willing to pass along would be very much appreciated.

Take care!

 

[Andiamo]

I have this noise too. I have 132,000 miles on my truck and I have had this noise for as long as I can remember. I'm sure it started sometime after the warranty had expired. Anyway, I mostly hear it when the windows are down and I'm driving next to a building or wall where the sound bounces off the object and back towards the my ear. I have no clue to what it is and definitely hasn't gotten any louder over the years. I thought at one time that it could be my emergency brake cable bouncing around, but I checked and it is pretty tight. If you figure it out, please let me know.

 

[FL G8R]

I have this noise too. I have 132,000 miles on my truck and I have had this noise for as long as I can remember. I'm sure it started sometime after the warranty had expired. Anyway, I mostly hear it when the windows are down and I'm driving next to a building or wall where the sound bounces off the object and back towards the my ear. I have no clue to what it is and definitely hasn't gotten any louder over the years. I thought at one time that it could be my emergency brake cable bouncing around, but I checked and it is pretty tight. If you figure it out, please let me know.

Andiamo-

That is exactly when I hear it the loudest...when I am next to another building, fence, or car. It isn't there when driving at high speeds and it doesn't have any affect on my Explorer's performance, it just drives me nuts (because it has been like this for over a year now). It isn't the cat (I have had that replaced)-- but like I said, I am pretty sure it is something with the exhaust.

Anyways, I am going to try one other place around town and see what they come up with. If anyone on here knows what this potentially may be, you will be of more help than two shops I have gone to. Thanks in advance!

 

[pwkunde]

I asked my mechanic if he thought it could be the PCV valve. He said maybe. I've never heard a bad PCV valve, so I'm not sure if this is a legitimate possibility (could the sound originate from the PCV, bounce around, and sound like exhaust?). Let me know what you guys think.

 

[FL G8R]

I asked my mechanic if he thought it could be the PCV valve. He said maybe. I've never heard a bad PCV valve, so I'm not sure if this is a legitimate possibility (could the sound originate from the PCV, bounce around, and sound like exhaust?). Let me know what you guys think.

pwkunde-

Thanks for the reply. The PCV valve has not come up in any conversations I have had with mechanics to date, but then again the rattling remains, so I am open to anything. I am having some minor work done on my explorer today so I told the guy to muck around and see what he could find.

He is pretty sure it isn't the driver side Cat, but it could very well be that one of the plates around that area has slipped off. I think that was mentioned in an earlier post, so we'll see what he finds out.

One of the reasons why I have always assumed the noise was an exhaust issue is because that is the first thing every mechanic said and it occurs during de-acceleration/idling.

I'll see if the guy can find anything.

 

[pwkunde]

I agree. It seems like it has to be something with the exhaust. A few weeks back I used a long metal rod and put one end up to my ear and the other end on various parts of the engine/exhaust to see if I could pinpoint the source of the sound/vibration. Needless to say, after trying every possible location, I came up with nothing. I really hope your guy finds something today. Good luck.

 

[FL G8R]

I tried to do the same thing as you, but had no luck. Part of the problem is that whenever I am in park, I don't dear it. Only when I am slowing down/coming to a stop. I had my girlfriend drive it around and slow down where I was standing to see if I could pinpoint it (pretty comical scene), but that was useless as well. All I know is that it is coming from the front end, likely the driver side. But given that the sound bounces around, I could do no better than that.

Anyways, I'll see what turns up. Unfortunately it may be something that I will have to deal with until it is time to buy a new ride.

 

[AMMO_HOOAH]

Just crawl under it and hit the exhaust with your hand. If it's exhaust related you should be able to induce the rattle yourself, and that would make it easier to find too.

 

[ThePhoenix]

just dont do that AFTER driving it...do it when cool...

I figured you should post a warning with that advice

 

[MiamiFEX]

Idle noise (rattle)

I just wanted to join in and mention that I too am hearing this rattle (140,00 miles). Very strange.

I have also been told it might be the catalytic converter or something in the exhaust. No success yet.

Adding to the cases already collected, I'll say that my rattle occurs pretty much only during idle. Once I rev up the engine, it's gone. And I also do not notice any lack of engine performance.

 

[lindleyt]

Same as MiamiFex, exactly.
Tim

 

[aggyaggy]

similar problem here

 

[Tozzi]

I had a rattle that sounded similar to that...kind of random and it was ONLY when in Drive and at idle...replaced my exhaust cat back (cats were fine) and it eliminated my noise...but i have another noise now from the front up under the engine jeeeeeeeeeeze

 

[hworksinc]

I've got a similar noise - only at idle with a warm engine, more often when in gear or when the A/C is on. Noise goes away at above ~1200 RPM and does not come back. I used a stethoscope, and I'm pretty sure the problem is the alternator - it sounds like there is a bad bearing and the alternator shaft is rattling back and forth. I've yet to pull the belt to confirm, but I'm pretty confident since I can feel the clattering when touching the alternator case.

Dunno if this is the same as yours, but it's worth checking.