kdailey4315
NAXJA Forum User
- Location
- Pacifica, CA
This is a video of a cold start. The noise does go away after a little while and it runs quiet and smooth.
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Piston Slap or Exhaust Leak?
- Thread starter kdailey4315
- Start date
This is a video of a cold start. The noise does go away after a little while and it runs quiet and smooth.
1990heepxj
NAXJA Forum User
- Location
- Apple Valley, Ca
an exhaust leak will make the sound always being warm wont make a difference
JJacobs
NAXJA Forum User
- Location
- Fort Collins CO
1990heepxj
NAXJA Forum User
- Location
- Apple Valley, Ca
read what he said under the video it says it goes away after a bit which an exhaust leak doesnt go away til you fix the leak
JJacobs
NAXJA Forum User
- Location
- Fort Collins CO
I know. You're wrong. Exhaust leaks routinely disappear when warmed up.
1990heepxj
NAXJA Forum User
- Location
- Apple Valley, Ca
huh, ive never heard of that or experienced it that way. ive had 2 diff exhaust leaks one started from a barely loose coupler while totally warm and my xj now has one 1.5 in. long crack in the header and the exhause leak is always there. there should be no reason for the exhaust leak to quiet down if its got air flowing through it should make the sound in my thinking.
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JJacobs
NAXJA Forum User
- Location
- Fort Collins CO
Perhaps you need to get some more experience before you offer advice on the subject. 
http://tinyurl.com/yelzktw
Seems common enough, huh? They won't always go away when warm, depending on where it is.
http://tinyurl.com/yelzktw
Seems common enough, huh? They won't always go away when warm, depending on where it is.
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1990heepxj
NAXJA Forum User
- Location
- Apple Valley, Ca
ok basically the difference is if its leaking from a joining spot or a crack. my bad but makes sense why mine has to bug the hell out of me always.
Yea it's not like metal expands at all after it warms up right? :kissyou:
1990heepxj
NAXJA Forum User
- Location
- Apple Valley, Ca
well i kinda just assumed by my wee little 2 experiences but mines got a hair line crack right on the header and its always there. drives me nuts but i gotta take the heat shield and fuel rail out to get to it which means doing that at an exhaust shop which im a bit lazy to do right now.
HenryKrinkle
NAXJA Forum User
- Location
- WI
Yeah, sounds like an exhaust leak. I just did my manifold: it would start REALLY bad and then get tolerable. It was cracked all the way around #4 and #5 where they are welded to the log. You could get underneath and try to see it smoking- works better when it's cold outside.
1990heepxj
NAXJA Forum User
- Location
- Apple Valley, Ca
well mine i see from the top its at the weld to the "log" on #4 tube
- Location
- Charlotte NC
WELD THAT MOFO! its that manifold.
kdailey4315
NAXJA Forum User
- Location
- Pacifica, CA
I drove it around a lot today. The noise doesn't go away when it's warm like I thought. It is loud as hell under acceleration and is "quieter" when not. I'm thinking it's an exhaust leak because I'm pretty sure I can hear the engine rev smoothly behind the noise.
I'll try to get a sound/video clip of it under acceleration.
I'll try to get a sound/video clip of it under acceleration.
sjx40250
NAXJA Forum User
- Location
- Alexandria VA
Under acceleration the engine is rotated and opens the crack because the crossover pipe doesn't rotate with the engine.
Noise presence will be dependent on crack location and temperature. It is not dependent on the failure mechanism, that is why sometimes it shows up after warming up or disappears after warming up. It is also common for the failure mechanism to be the same between vehicles causing repeatable symptoms. I thing you are both right.
Noise presence will be dependent on crack location and temperature. It is not dependent on the failure mechanism, that is why sometimes it shows up after warming up or disappears after warming up. It is also common for the failure mechanism to be the same between vehicles causing repeatable symptoms. I thing you are both right.
