Rattle in the back of my hearse.

[Uglybastard239]

This may sound like a no brainer to some of you, but I've got an issue that I can't figure out. Every time I go down a bumpy or even a rough road it sounds like something is trying to shake itself loose from the back of my hearse.

I took it to a local muffler guy and he says the pipes and hangers are all good, but the muffler is probably what's making the noise. It's not like I don't trust the guy (even if he DID put a greasy, disgusting hand print on my hood) when it comes to exhausts, but can a muffler that isn't loud in the traditional sense REALLY make that much noise? Or could there be something else coming loose under my rollers?

It does seem to be getting worse since I scraped bottom coming out of an uneven parking lot, but I'm having a hard time believing the muffler could make THAT much noise.

Any help would be greatly appreciated.

[Abnorml]

Give a description of the sound, if possible. Check the rollers and make sure they are not loose. On most hearses you can look under the rollers and some there is enough room to crawl inside.
I don't know much about mufflers, but I think the quieter a muffler is the more baffles are inside.

[Uglybastard239]

Well, it's kind of like when you drive your mini van around with your spare tire in the back. It sounds like somethings rattling back and forth and bouncing around a bit. Something about the size of a rim, but it's too far back to be my spare and the rubber would probably muffle it a bit.

I can see back under my rollers, but there's no way MY fat ass is ever going to fit under them. I shined a flashlight back there when I was installing a seat onto my rollers (can't keep the kids out of the damned thing...coolest car ever!) and there IS stuff back there. I have NO idea what, but I gotta figure it came from the factory that way.

My muffler is so quite my dogs can't hear me pulling up the drive, but the muffler guy said that due to the length of the pipes the muffler doesn't actually have to do as much work as I think. In his defense the muffler and exhaust pipes were WAY cooler to the touch than I would have thought possible having run the car for 15 or 20 minutes before the inspection.

Hope that helps.

[Flymanj3]

With all the wood, panels, etc. in the back, and with such a large open area, just about anything can bang or creek and make a God awful noise. If it is worse after bottoming out, I too would check the Muffler / tail pipe first.

With mine, what I did was crawl under , grab the tail pipe (about the middle of the car) and give it a GOOD shake. First side to side, then up & down. While everything looked good and hangers all sound, I found a spot on mine where a good jolt would let the muffler tap the floor. After adding an extra hanger in that area, problem was solved.

[Beladona_13]

It is possible to have a baffle break loose inside the muffler and make odd sounds. If the exhaust is cool to the touch I would say run a back pressure test to see if said baffle is partially obstructing the flow of exhaust. Anything over 1 lb of back pressure is pointing to something restrictive. IE: loose baffle.

[Uglybastard239]

Hmm. Did a quick check online and it appears that a back pressure test kit will cost anywhere from 30 to 90 bucks depending on what and where I buy it. My muffler guy figures it's a baffle and it'll cost less than 70 to replace the muffler. Wonder if I should just replace it and see if that solves the problem. At least I'd know I had a spanking new muffler with a shiny new warranty.

Did I mention that my friend followed me up the (1/4 mile) drive the other day (long before the noise became annoying) and he told me my exhaust looked like it was going to fly off. The muffler guy assured me that exhaust was mounted on rubber hangers and a lot of movement was normal. God I should have paid more attention in shop class.

Any additional help or suggestions are greatly appreciated.

Glenn

[Morella]

You don't need a back pressure test kit. Do it the old-fashioned way. Idle the engine and hold your hand over the end of the tailpipe. Use a rag if it's hot, of course. Any exhaust leak will show up as a hissing noise. You can also look for carbon tracks around the muffler and exhaust.

If the noise is coming from underneath the vehicle, put it up on stands and get under it, just push everything up and down and listen, particularly the exhaust system, but the fuel tank, and anything that mounts underneath the vehicle.

And it is possible that an internal baffle in the muffler could be bad, causing the noise, but a back pressure test kit most likely won't show you that, unless there is some computerized technology that you can buy now to analyze your muffler, which I wouldn't waste my money on.

Best of luck, and anything I can do for you, Glenn.

-denise

[Uglybastard239]

Thanks for THAT info. High tech tests like pushing, pulling and putting my hand over things are the answers I like to get. My shop teacher was a "any problem can be fixed by hitting it with a hammer...if that doesn't work get a bigger hammer" kind of guy. So high tech testing kits make me start seeing unnecessary dollar signs.

Oh, update on the "type" of noise. I drove her around today and the noise definitely sounds like I've got something bouncing around in my trunk.

I'll crawl around under her tomorrow, if the weather holds up. I've got to take her out and try finding a hood ornament anyway.

Thanks again.

[Beladona_13]

A back pressure test kit isn't to check for leaks... it's to test for back pressure, IE: plugged exhaust, perhaps from a broken baffle. And it's not a fancy high dollar kit, just use a vacuum gauge that also reads pressure. like this:

http://www.harborfreight.com/fuel-pump-and-vacuum-tester-93547.html

for $12.99! Drill a 1/8" hole before and after the muffler, compare readings, if there is more than 1 to 1 &1/2 pound of pressure, you're muffler has issues! This test also works for Catalytic converters. Then simply plug holes with self tapping sheetmetal screws or a quick spot weld when finished.
On the other hand, if you've narrowed it down to something inside the car rolling around, all of this is a moot point.

[Morella]

I like that answer. Simple ones are always the best. Just be sure that there is enough left of the exhaust pipe to put screws into...they won't cut threads into rust.

-d

[Uglybastard239]

And God so loved the world that he allowed Harbor Freight to be created. I LOVE that store and 13 bucks is a much more reasonable price than 30 to 90 for something I'm probably only going to use 3 or 4 times (max) in my life.

I haven't narrowed it down to anything at this point. Like I said, I'll be doing some crawling around tomorrow to see what shakes loose. Maybe I'll even try stuffing a small child under the rollers to see what's hiding back there. Who says child labor is a bad thing?

Glenn