Muffler rattling diagnosis

[sixsix]

That's a flat-ish piece of metal like a heat shield. I can tell by the sound. check the one ON the muffler.
You can excite the metal by putting a bare loudspeaker against it, playing bass music.

Whew... someone's thinking! Augi, you are soooo gullible and fun on the forum to boot!

Good Luck, 629 !!

[augidog]

we shall see...but I still think the clunk is too solid to be a shield.

who knows, I just might be wrong for the first time in my life

[MechBob]

I would have them check the
fan clutch,motor mounts and flex plate,also.

[MechBob]

oh,your ramps are fine,also.

[Godron629]

Ok. I'll check those things tonight.

I'll take a ratchet tie down and secure that heat shield - see if makes a difference. Surely it won't get too hot

(yeah cmon man I spent like $100 on those )

(I now see this: https://www.astrosafari.com/viewtopic.php?f=24&t=113858 and it smells just about the same)

[Godron629]

Ok

It does not happen idling in Park or Neutral, it might happen parked in Drive - say, at a stop sign, briefly.

First I ratchet strapped the heat shield to the muffler - this did not help.

Then I started focusing on different areas. This bar extending from the spare tire up to the bottom of the rear door was "loose" and it seemed a good candidate for rattling - this did not help.

There was also a ton of gravel in the rear bumper - this did not help, but made me dirty.

Then I found that this "bracket"-y type thing around the left-rear brake would rattle if I moved it. It was not easy to move but struck me as something that would act like a tuning fork, so I stuffed some shop towel in there - this did not help.

Around the same place, there was a great many number of rocks between the gas tank and its plastic shield. I did not resolve this, but I suspect it is not the issue.

I took this video to know what it sounded like outside the van. I was also curious if the drive shaft rotated any other time than moving (I was considering grinding diff gears at this point)
https://streamable.com/vb7ge7

I could reliably reproduce it at a stand-still in Drive, with the emergency brake on, barely pushing the accelerator (which is what I'm doing in that video^).

But! there was a woman in another van in the university parking lot near me, so I asked her if she would help me by revving the engine slightly while I was underneath it. I agreed that the windowless white van and overalls were indeed conspicuous and assured her I wasn't Ted Bundy nor Buffalo Bill - and she did.

I put my hand on the muffler (can, as I have called it) and it rattled hard along with the sound, and only when the sound could be heard.

So, I think there is almost certainly something inside of it that is loose or from upstream. I am not sure if this is a satisfactory conclusion, yet, but I am happy it is rattling and not grinding.

[augidog]

...

[Godron629]

unrelated, but this is my van

[augidog]

I put my hand on the muffler (can, as I have called it) and it rattled hard along with the sound, and only when the sound could be heard.

So, I think there is almost certainly something inside of it that is loose or from upstream. I am not sure if this is a satisfactory conclusion, yet, but I am happy it is rattling and not grinding.

I bet if you held the muffler still, and moved only the tailpipe, you'd get your noise.

did I mention anywhere that I ran an exhaust shop for 12 years? I musta forgot to.

[Godron629]

...

Do you mean do something like this? I assume you mean the red arrow action?

(also no, but thank you for your help )

[augidog]

I was editing and trying to keep up with your replies. I screwed up the quote while you were posting it, so I edited my second reply. fun with forums!

nice drawing! I should print that & put it on my fridge
the green arrows. but just gentle, not like wrestling a gator.
it might be the inlet tube, but I'm pretty sure it's the outlet.

I was happy to be of help, this forum has always been there for me.

if it matters, I think you did an excellent job of keeping us up to speed. you really wanted to find that noise, Buffalo Bill, and I would have too. I'm sure I'm not the only one who appreciates your sense of humor...there's always room for one more in chat

[sixsix]

oh,your ramps are fine,also.

Yeah, Bob, but you are not under them. Rhino Ramps and the Max version have a REAL BAD rep.
An easy search and read.

Rhino ramp 10.jpg (40.99 KiB) Viewed 463 times

OMG - there are a lot of pics of these $50 ramp POSs
And you paid $100...?

...The company that made Rhino ramps several years ago went into bankruptcy partly due to claims regarding product liability.

Here are the "old school "Heavy Metal" ramps I was referring to.
I have seen "New" metal ramps that 'look' ok, but the steel is a much lighter gauge.
These yellow ramps weigh easily 30lbs each and have been around for 2 generations.

I am the 3rd owner:

One bummer is that low front overhangs require a ramp for a ramp.

We also use Stands and 4x4 Cribbing if needed. Nice to have around for confidence.

[sixsix]

OMG.jpg (63.81 KiB) Viewed 458 times

geez, OMG, that's just creepy.

[augidog]

about the rhino MAX ramps...I trimmed all the excess material off the bottoms, there were some big gobs that interfered with a flat seating, which I can guess would lead to splitting and failure.

71Q7WMCWddL._SL256_.jpg (12.62 KiB) Viewed 436 times

stock photo, not "max" & not mine, which I trimmed before 1st use.

note: I still set jack stands after the van's on the ramps.

[Godron629]

I'll look into getting some metal ramps. (I do however have jackstands underneath! )

There is a guy around where I live that perpetually has a VW Jetta on 4 metal ramps and I am jealous. I have no jack, yet - historically most of my substantial maintenance takes place 4 hours away in a stocked garage, but that's getting old.

They were on sale for $50 CAD at princess auto, but I missed the sale - figured I'd just get them anyways, I was there for something else.

[M_a_t_t]

about the rhino MAX ramps...I trimmed all the excess material off the bottoms, there were some big gobs that interfered with a flat seating, which I can guess would lead to splitting and failure.

71Q7WMCWddL._SL256_.jpg

stock photo, not "max" & not mine, which I trimmed before 1st use.

note: I still set jack stands after the van's on the ramps.

Same procedure here. Sweep drive way to get small rocks and sticks off. Drive van on ramps, put stands underneath and then work on it.

[sixsix]

Perfect !!

No hard feelings, Bob, I hope, I hope.
LOL

[Leeann_93]

I have a set of the heavy yellow metal ramps that I got ~30 years ago at pep boys in Dover, DE. Those things don't care what I drive up on them, they've never flinched.

I did, however, when one dropped on my big toe while I was standing on concrete. Broke it through and through just below the nail (you can still feel the ridge). That didn't feel good, but I did complete the oil change on my roommate's car before going to the ER.

[K-TRON]

I have the same problem with my 97 Safari Van. The exhaust makes some rattling noises when the engine is cold. After about 90 seconds the noise goes completely away. I have been thinking about pulling the entire muffler off and blowing it out with my backpack blower to see what comes out. The last time I took a muffler off a vehicle I found half of a turbocharger wedged inside the muffler. I couldnt hear anything unusual on that vehicle, the two stroke diesel cannot be tamed to reasonable noise levels.

Chris