Sudden: intermittent rattle + vibration in floor board + loud exhaust

[cross6]

Only happens from 600 to 1000 rpm in park or gear. All of it goes away immediately when engine gets above 1000 rpm.

Doesn't do it under load.

It's a combo of three things:

1. Rattle is a weird combination of a rc car whine + metallic chatter. It starts and stop every few seconds. Can be heard 360 around truck, just as loud standing behind truck as in front.

2. I also feel a cyclical vibration in the floor board like a bad u-joint, but the truck isn't moving.

3. Exhaust is suddenly loud and rumbles.

But once you hit 1000 rpm, park or in gear. And ALL THREE stop together. I'm so stumped.

No codes. Listened with stethoscope, can't find it.

 

[broncojunkie]

What motor do you have? And does it happen when cold or at operating temp or both? Is it louder under the hood?

I don't really have a clue, but I know it's sometimes hard to explain a noise. Maybe if I heard it, I could make more sense out of it.

 

[ROBinGa]

Check the heat shields around your exhaust. We had a similar issue with a rattling noise at idle and one of the heat shields developed a hairline crack. The crack allowed the metal that met where the crack developed to vibrate and rattle against each other making a very loud annoying noise. Any increase in engine rpm like while driving and it didn't happen, only at rest and in idle. I was able to bend the shield edge slightly so that the two sides at the crack don't touch and the noise went away.

 

[cross6]

What motor do you have? And does it happen when cold or at operating temp or both? Is it louder under the hood?

I don't really have a clue, but I know it's sometimes hard to explain a noise. Maybe if I heard it, I could make more sense out of it.

4.0 2WD. Does it hot or cold. Louder when standing around the truck. Don't really hear it as much when you lift the hood and listen over the engine.

 

[broncojunkie]

I like ROBinGA's thinking. A loose, vibrating heat shield could cause the noise and vibration AND it could echo through the exhaust system, sounding like the exhaust is getting louder.

Also, look for something that would be affected by the motor torque. Increasing engine rpm produces more twist and could close up the gap of something with a close clearance. Like Rob says, a heat shield...maybe even a broken exhaust manifold stud or loose/broken motor mount. Check your cats, too.

Also, while it's making the noise, cap the tailpipe off momentarily with a rag bunched up in your hand. If there is exhaust escaping somewhere, you will hear it. If it builds up pressure, your exhaust is probably good, at least as far as leaks/broken studs/etc are concerned. You still could have some internal issues with a cat, but I think those just normally rust out or start overheating.

Maybe someone will correct me if I'm wrong. Can a bad cat rattle internally at low rpm?

 

[ROBinGa]

To further my story. Our Ex was making noise so loudly and it worried me so much that I took to a shop. They poked around and even said they used a stethoscope to listen to drivetrain and were telling me it sounded like the transmission was source of the rattling and noise. Gave me a quote and I drive home to think about it. At home I crawled under to just look for myself and almost immediately saw the corner of a heat shield had the crack. No doubt it did vibrate and the noise was being picked up by stethoscope in any part attached to the truck. Can't begin to tell you how loud and bad that noise was. It sounded like big trouble but was so simple as to why once I found it. I never have replaced that shield and it's still solid and doing it's job, just that the little crack is wide enough after I bent it so pieces don't touch and vibrate anymore. Hope your issue is something similar.

 

[cross6]

Ok cool thanks guys I will get under the truck this weekend and look for loose shields!

 

[cross6]

update: Can't find a heat shield rattle. Ran engine without belt. Still there. With the belt off and no fan noise I could tell it's coming from the right rear of the engine so given I have a 4.0 with ~190K I'm guessing it's timing chain time.

 

[CaliGirl]

We have a 2013 Explorer that has the rattle/vibration. It occurs most notably at around 18mpg and again at 43mph. Our Explorer has been with Ford for discovery and repair for two months (yes..warranty). They have replaced the axles, motor mounts, transmission, engine and most everything else and the problem still exists. Ford has even sent an Engineer out to work on our vehicle full-time starting a few weeks ago. It seems like this problem is pretty wide-spread on this car, as additional Explorers have come in for the same problem since ours has been there. So, if you have this problem, don't change the transmission, torque converter or anything else because it won't work. I have my suspicions as to what the problem is we'll see if they figure it out. Would be interesting to know how many people have this problem. It's definitely more prevalent on the passenger side.

 

[D Hook]

Two months and they can't find a rattle?!!

 

[madanna102]

I have a 2013 Ford Explorer and have the same exact problem. First time I brought it in they said they couldn't find anything. 2nd time they had the truck 1 week and they replaced axles and other things. It still isn't fixed. Now we are waiting on a Ford Engineer to tell them what is wrong.

I have bee having this problem since we bought the truck. I am beyond disgusted.

I would never buy another Ford. I had my CRV for 13 years and never had one problem with it.

 

[CaliGirl]

Well, it's July and our Explorer still isn't fixed. The dealership has washed their hands and suggested we go lemon law. The Ford dealership has had it for most of 2014 - although we have it back now. It's actually scary to drive, as it rattles terribly, the steering seems to intermittently be difficult, the car pulls and we have this horrible clicking noise when turning and breaking.

Ford factory sent two separate engineers out to look at our car. They couldn't fix it and they didn't offer to replace the vehicle. We have had to go lemon law on them.

Madanna102 - tell your dealership that they had another Explorer with the same problems at the Tuttle-Click Dealership in Irvine, CA. Maybe they can figure it out.

We are just hoping to get out of the vehicle before anyone gets hurt and we will never buy Ford again!!!!

 

[D Hook]

CaliGirl and Madanna102: These are both 2013 model year vehicles, correct?

 

[SyberTiger]

Maybe someone will correct me if I'm wrong. Can a bad cat rattle internally at low rpm?

Absolutely! I've seen (heard) the CAT rattle only when at idle and it seems to go away when driving. This was a recent situation with a Chevy Blazer. I suppose part of the ceramic honeycomb within the CAT starts to break loose and the frequency of vibration at idle is what allowed it to rattle so loud. I thought about this when I read the OP's comments but he never came back all these months latter to fill us in on what the outcome was.

 

[CaliGirl]

Yes....2013