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Unread 02-27-2013, 07:58 PM   #1
kjg26
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1993 YJ Wrangler 
 
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Cracked manifold?

I purchased a new exhaust manifold for my 93 from 1 A Auto. After pulling the Thunder it appears the manifold that is on there is 1 of the newer styles with the flex joint. I'm thinking my exhaust manifold may not be cracked or leaking it may just be a loud exhaust system. Is there a way to test if the exhaust manifold is cracked or not

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Unread 02-27-2013, 08:04 PM   #2
demonz0
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I would test by starting your Jeep after its been sitting/cold and run your hand all around exhaust feeling for the warm air puffs coming out. How I found both of my cracked manifolds.
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Unread 02-28-2013, 05:53 AM   #3
nembudonna
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I had to replace my head gasket and ever since then it's a little louder. I think mine's comming from where the exhaust pipe meets the manifold. There's no donut there.
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Unread 02-28-2013, 06:28 AM   #4
willawolfe
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I don't know exactly how to but you may look into using smoke. May just be a technique used to find vacuum leaks, maybe someone else could shed light.
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Unread 02-28-2013, 06:35 AM   #5
EABiker
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Quote:
Originally Posted by willawolfe View Post
I don't know exactly how to but you may look into using smoke. May just be a technique used to find vacuum leaks, maybe someone else could shed light.
Do a Seafoam treatment; you can clean up the carbon deposits and generate smoke for the leak test. Have someone cover the tailpipe with their shoe with the engine running; it will force more exhaust gas out of the leak.
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Unread 02-28-2013, 06:44 AM   #6
Que89YJ
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You need to disconnect rad fan. The pipe method its good at isolating any noise. Are you blowing an O2 fault?
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Unread 02-28-2013, 06:56 AM   #7
kjg26
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No fault codes. Just noisy. Disconnecting the rad fan will be easy with the taurus fan!!! So stop the fan. Shoe over the pipe and run seafoam through the vac system. Check for smoke...?
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Unread 02-28-2013, 08:06 AM   #8
Que89YJ
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You can do it with a cigarette or an insense stick. Just look for the smoke being push by a leak. If you had a diagnostic ttol that could read the O2 sensor voltage you would monitor the O2 sensor and spray with carb cleaner and look for the voltage spikes.
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Unread 02-28-2013, 12:23 PM   #9
TexasYJ
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One trick I have used in the past is to take a 4' - 6' length of 1/4" tubing, insert one end in your ear and use the other end as an audible "sniffer" to test around the joints of the manifold. Once you find the spot, you will be able to hear the noise through the hose. Cheap and dirty stethoscope. Be wary of fans and belts when using this techniques, though.
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Unread 02-28-2013, 01:17 PM   #10
Que89YJ
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That is the pipe method. It works really well because you can block all the noise out except what you have at the end of the pipe.
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Unread 02-28-2013, 02:49 PM   #11
TexasYJ
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Originally Posted by Que89YJ View Post
That is the pipe method. It works really well because you can block all the noise out except what you have at the end of the pipe.
Sorry, Que I missed your post regarding that method....
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Unread 02-28-2013, 08:21 PM   #12
Que89YJ
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I didn't explain it at all you did. Thanks. Swipe on the cells helps but is a pita besides nice know we are thinking the same thing!
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Unread 03-04-2013, 02:52 PM   #13
TexasYJ
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Originally Posted by Que89YJ View Post
I didn't explain it at all you did. Thanks. Swipe on the cells helps but is a pita besides nice know we are thinking the same thing!
Que, you an I generally tend to end up on the same page in most of our posts!
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Unread 03-04-2013, 03:49 PM   #14
Que89YJ
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Then I am in good company.
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