Hiss coming from a Merc' Tracer

I know, I need to get the car in to a shop to have it checked out, and any suggestion here is going to be just a guess, and probably not even a close one.
BUT, you never know. And if I can get even just an idea of what the problem might be, then at least I can go in the shop not completely uneducated.
I have a '97 Mercury Tracer, automatic with 99,9000 miles on it. When it's running (so far as I know, in drive as well as in park,) there's a hiss coming from the engine. It's quite audible, and with the hood open, it sounds like it's coming from the back center, betreen the engine and the passenger area. Around where the oil dipstick is. I've looked and looked while idling, and I can't pinpoint it. I can't see any escaping fluid or steam, or anything to indicate where the hiss is coming from. But it stops as soon as I turn off the engine.
Any ideas? Thanks!! Liam
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exhaust leak???

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Hmm, I don't know. I'll look closely at the possibility. Would the hiss sound as prominent as it does from the top of the engine if it might be exhaust? Come to think of it...when it idles, I think I do smell exhaust....
Liam
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After thinking about it, the hissing sound may be a vacuum leak. I would start by looking at all your rubber/hard plastic lines first for a possible vacuum leak. If no joy, then look close at any exhaust paths from the top of the engine bay going back towards the firewall.

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"el lobo" wrote

And if you can't see anything, get a piece of rubber hose (vacuum hose works nice) a couple of feet long, stick one end in your ear, and wave/poke/prod the other end around the general area of the hiss. Shouldn't take more than a minute to zero in on it.
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"> And if you can't see anything, get a piece of rubber hose (vacuum hoseworks

That reminds me of the old broomstick in the ear tool. Listening for strange mechanical sounds.......
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Thanks! Great idea. =) Will give that a try. Liam
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Would you believe I can't find a darn piece of hose to use? Except maybe one from the engine somewhere. =)
Anyway, I've closed in on it otherwise, I think to just to the passenger side of center along the back of the engine area. Just barely closer to the firewall than to the engine I think. And if it matters, the hiss seems to last about 2-5 seconds after the engine has stopped. Think that can indicate anything?
Thanks for any suggestions. =) Liam
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I'm thinking vacuum or air leak (from the air intake). Check all of these. If it really is an air leak or vacuum leak it should be affecting your idle, but unless you have a tach you might not notice so easily.
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Looks like that's it. (Pardon my lack of proper termanology) There's a hose of some sort that comes out the top of the...engine I have no idea what part of it) and makes a 90-degree angle before heading off somewhere. There was a little slit in the hose right at the 90-degree bend. Can't afford a hose right now, so I did as good a job duct taping it as I could...and that stopped the hiss. AND, the other problem I indeed was having was that it was constantly sputtering and dying when idling in Drive or Reverse. That's stopped now. It still seems to idle a little low...but at least it no longer threatens to stall. (Perhaps changing the air filter will help?)
Thanks for the reply!! Liam
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On Tue, 25 Nov 2003 22:21:49 GMT, LRW wrote:

Definitely check the air filter if you aren't certain it is good and clean. It only takes a minute to check or replace, and only costs a couple dollars for a new one. A dirty air filter will only hurt, not help, the engine.
-D
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They're actually $10-15 on 3rd gen models.
Good thing I bought a bunch for $1.25 each when Kmart unloaded them :)
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It's possible that the computer was compensating for the vacuum leak, so now that you sealed it (or lessened it), it'll have to figure out what to do to adjust the idle to what it should be.
BTW, they tend to idle at 600-650 at in drive...not sure if that's what you're getting.
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