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Discussion Starter #1
When my cars cold it sounds somewhat like a motorcycle. I'm almost positive its the serpentine belt. Cuz its not an exhaust noise but from the engine bay. But it goes away once the cars been driven a little. Quite simply, the sound is annoying and makes my car sound weak lol. Is it just an old belt causing this?
 

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No, a serpentine belt would not cause it to sound like a motorcycle. Bad timing or misfire would though.
 

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Before I killed it, our 94 did this. It was exhaust. The exhaust manifold closest to the firewall was slightly loose to the head so you could hear exhaust noise until the manifold warmed up and expanded, sealing itself.

Failing that, if you have an SES/CEL light on, have the code read. It might be something in your secondary AIR system.
 

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Discussion Starter #4
There's no codes whatsoever. I find it hard to believe that its misfiring, as it runs fine, pulls strong and idles regularly. It just sounds weird. I'm almost positive its the belt... Cuz thats where the sound seems to be coming from. But I guess the exhaust manifold thing could be possible. But wouldn't that cause a CEL?
 

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QUOTE (wildaaron @ Apr 8 2009, 01:53 AM) index.php?act=findpost&pid=716167
....But I guess the exhaust manifold thing could be possible. But wouldn't that cause a CEL?[/b]
It never did on my 94, but that was OBDI. It certainly would have thrown a code if the gap stayed open because the downstream 02 sensor on that bank would have found something wrong with the exhaust gas contents.

You might check the tubing to/from the PCV valve as well, as blowby might be greater before the engine parts warm up and settle in.
 

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The Topic Finder in the top navigation bar has a "PCV location" under the Vulcan heading, which links to this thread: http://www.taurusclub.com/forum/index.php?...2017&hl=pcv

(Just the pic in post #1, and the OP's label is correct, (1) is the PCV valve - rest of thread is strange....)
 

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Discussion Starter #8
The PCV valve seems to be on there fine. I mean I wouldn't call it tight. But its not loose either. Is it ok to take the PCV valve off with the car running?

And upon closer inspection, the sound might actually be from the exhaust manifold... Although the PCV valve and exhaust manifold are very close to each other so I can't exactly pinpoint it. If it was the exhaust manifold I'd just need to tighten up the couple of bolts and it should seat up fine to the head right?
 

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It's more the tubing from the PCV to the intake manifold that causes problems. It sees a lot of muck and acids from engine combustion, contaminated oil, etc., so it tends to crack or rot out.

If the manifold is loose, you can try tightening it. The real fix would be to remove the Y-pipe, remove the manifold, and replace the gasket. Problem is, if rust or crud has crept into the space between the manifold, gasket, and head -- or the gasket has eroded in the hot gases -- tightening it may not altogether seal it.

There's always the fun chance that the manifold is cracked (the crack might close up as the manifold expands under heat).

If from a cold start, you strongly smell exhaust at the back of the engine, then PCV valve/tubing is leaking or the manifold and/or manifold to y-pipe connection is loose.

I could smell the exhaust on the 94 with the loose manifold, but by the time I could get out of the car, lift the hood and look under, the leak would be closed up. I finally discovered it when I removed the upper and lower intake manifolds and could see the carbon tracks from the leak.
 

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Discussion Starter #10
Wow removing the y-pipe? I didn't think this would be that serious. Well I know I don't smell any gas at start up. And it definitely takes more than a minute to stop sounding like that (as yours did). I don't know what to do...
 

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Another question - is the sound definitely like an exhaust sound? Like the exhaust note of a Harley?

Or is it a clattery, loud ticking? If the latter, you might have a hydraulic lifter that's leaking down. Once it pumps up, the clattering will quit.

If it's both (clatter and exhaust note), you might have a sticking exhaust valve. Not a common thing on the Vulcan. But, neither is a hydraulic lifter problem either.

Since you're in Cali, you might look closely at your secondary AIR system... I know from experience that a hole in the air feed pipe to the exhaust manifold is very noisy. But the hole also usually causes a SES/CEL light to illuminate. (Mass. cars have the secondary AIR system as well, at least the 98 does -- I don't see it / haven't found it on our 04.)
 

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Discussion Starter #13
Ok so I recorded a video clip so you could here the sound. I don't have a camera so I unfortunately had to use my webcam. Here's the link:

http://www.youtube.com/watch?v=AxgMRLl-gxo

You might have to turn the volume up alot to really hear it.

Obviously my car doesn't sound like that when I revved it those two times, but the camera just picks up sound weird. However, the truest sound comes towards the end of the video.

And...I think I smelled a little gas this time.

FML.

What do you think?
 

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If the most characteristic capture is at 0:33, then I'd guess, and it's only a guess (and assuming it all goes away when the engine warms up):

exhaust manifold to Y-pipe loose

exhaust manifold to head loose

y-pipe to catback loose (under car)

The good news is -- guessing again -- that a cracked manifold would not have such an obvious open-exhaust sound. At least, not a crack small enough to close up when the manifold heats up and expands.

Your sound is an open exhaust sound. Here's a similar sound (at 0:29) from an engine with NO pipes or muffler (on my favorite piston-powered aircraft): http://www.youtube.com/watch?v=vyuCGuP6TNQ.

Or 0:28 here: http://www.youtube.com/watch?v=Ihgz7opXci4...feature=related
 

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Discussion Starter #15
Well that is somewhat good news.

Just letting you know, a while back my car was straight-piped with no muffler or resonator. I got a fix it ticket and so back on went the muffler and resonator. When it was straight-piped, the exhaust was cut right after the cat and the straight pipe was welded on. Could this have anything to do with this at all? Could it have to do with the cat or are you pretty sure its likely the manifold?

And also, I only have single exhaust so as far as I know I have no y-pipe...
Thanks for all your help by the way.
 

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No y-pipe? Something has to tie the exhaust from bank 1 to the exhaust from bank 2, unless you have 2 completely separate exhaust systems, two pipes, two sets of cats...

I'd take a close look at where the exhaust was cut and welded.

A cat with loose guts will rattle (internal baffles / catalytic medium container rusted, burned or broken), but I can't imagine a way to both have open exhaust and then have it go away when warmed up on the cat, which can get VERY hot.
 

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Discussion Starter #17
Ok you win on the y-pipe thing. I guess I'm thinking more in the terms of a "post-cat" y-pipe that splits into two and eventually two mufflers, tips, etc. I'll have to slide under there and take a look at how well it was all re-welded. Otherwise, do you think a small exhaust shop would be the ideal place to go for something like this?

Like I said, there's no CEL so its hard to pinpoint the true problem.
 

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QUOTE (wildaaron @ Apr 9 2009, 03:03 AM) index.php?act=findpost&pid=716449
do you think a small exhaust shop would be the ideal place to go for something like this?[/b]
One means of diagnosis is not open for you -- looking for steam or visible exhaust. We in the Northeast are of course blessed with 8 months or so of weather that brings us all the benefits of cold ranging from bitter to merely 40s bone-chilling. In Long Beach, you're stuck with all that lousy sunshine and warmth, so there's no simple visual diagnosis open to you...

As for the shop: sounds like a plan. That or an independent repair shop. Or a community college.

That fact that there's no CEL/SES suggests that the exhaust leak is beyond the sensors, though as I said, the loose exhaust manifold on my 94 did not result in a code.

Re: the latter. Tell the shop there could be a leak at the top of the exhaust manifold in the bank closest to the firewall. (Which is where mine was. It wasn't visible from the top thanks to the intake manifolds and it wasn't visible from the bottom when the car was on a rack, thanks to the exhaust manifold itself.) They will have to use a mirror.

They could also check (as could you) by getting a socket on the manifold nuts and seeing if any are able to be turned suspiciously easy. Without removing the upper and lower intake manifolds, you'll have to work blind on most of them. Go to Rock Auto or ebay to see the fastener configuration for the exhaust manifold for that bank.
 

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Discussion Starter #19
Alright well I'll have to take it in tomorrow before work.
First I'll have them just look at the exhaust underneath all the way through.
Then move on to the manifold from there. Ugh...
Thanks for the help.
 

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Discussion Starter #20
So I finally got around to taking it in...

There's a bolt thats loose on the exhaust manifold and he wants to replace the gasket while he's down there, as it could've been exposed to debris I suppose. And I have a leaking water pump. Both of which he showed me are in horrible places.

He said $800 for both because it would take a little disassembling of the engine just to get to them. Does that still seem kinda steep?
 
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