exhaust leak or something else?

E

eufo

New Member

Feb 18, 2006

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Miami, FL

Jul 17, 2006

#1

• Jul 17, 2006

• #1

i've got an odd thing going on with my car... at first i thought it was an exhaust leak, now i'm not so sure... to preface this, all times mentioned are with the windows up and a/c on... radio off to listen closely...

since i've been driving the car daily (about a week or so) on the freeway it was making what sounded like an exhaust leak under load coming from the engine area... i didn't think much of it and figured i would reseat the headers eventually or tighten them up...

yesterday was extremely hot outside... i drove the car into work (30 miles), and didn't hear the supposed exhaust leak at all! nothing! just pure exhaust from the pipes... which i was extremely happy with... but confused...

today it was cooler when i left for work... and the exhaust leak sound was back... all the way up here to this part of town... i stopped at home depot on the way in... afterwards it started getting really hot out again... as i drove from home depot to work i could tell it was getting hot, because i was burning up... suddenly the engine began idling a bit different (lower) and the "exhaust leak" disappeared as suddenly...

i'm worried there is something else going on here... not an exhaust leak at all... could i be hearing detonation??? if so, what might the outside temperature have to do with it? bad IAT sensor? any ideas?

 

94-302-vert

Active Member

Aug 16, 2004

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NE CT

Jul 17, 2006

#2

• Jul 17, 2006

• #2

I have an exhaust leak that I hear for the first couple minutes then it goes away... Started after doing my clutch and I haven't gotten around to tightenting the H-pipe yet.... So don't rule that out....

Detonation should get a lot worse as it gets hot and humid out, never better...

 

E

eufo

New Member

Feb 18, 2006

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Miami, FL

Jul 17, 2006

#3

• Jul 17, 2006

• #3

94-302-vert said:

Detonation should get a lot worse as it gets hot and humid out, never better...

Click to expand...

given everything else equal, that is true... but i'm wondering if the ambient temp is somehow creating a timing change that could be creating detonation under certain conditions...

 

E

eufo

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Feb 18, 2006

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Miami, FL

Jul 17, 2006

#4

• Jul 17, 2006

• #4

side note: EGR eliminated improperly (capped off), 93 octane BP Ultimate, 12* ignition advance

 

bill302

Active Member

Nov 2, 2005

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alabama,gadsden

Jul 17, 2006

#5

• Jul 17, 2006

• #5

i would check and tighten the header bolts and see what that does...i had the same problem that changed with motor and outside temps and i had 1 loose header bolt....tightened it and it was fixed....

 

BlackVert

15 Year Member

Oct 3, 2003

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Bethesda, MD

Jul 17, 2006

#6

• Jul 17, 2006

• #6

as the engine and pipes get hot they tend to expand. that may close up a small leak that is open when they are cooler.

 

E

eufo

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Feb 18, 2006

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Miami, FL

Jul 17, 2006

#7

• Jul 17, 2006

• #7

yeah, i'm going to go ahead and tighten up the header bolts... is this better to do when the engine is still a little warm or wait until its completely cooled off?

 

bill302

Active Member

Nov 2, 2005

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alabama,gadsden

Jul 17, 2006

#8

• Jul 17, 2006

• #8

a little warm wont hurt as long as its not hot enough to burn you...

 

BlackVert

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Jul 17, 2006

#9

• Jul 17, 2006

• #9

i think it's a 3/8" wrench

 

S

stangz4life

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Apr 8, 2002

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tampa,fl

Jul 17, 2006

#10

• Jul 17, 2006

• #10

yes i would deff go with what blackvert said.when you first start driving everything is cold as you drive the headers and whole exhaust system gets extreamely hot and im sure it expands a lil bit to seal up what lil bit of a leak you prob have.if possible try to do as warm as possible.

 

BlackVert

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Jul 17, 2006

#11

• Jul 17, 2006

• #11

i would say do it as cold as possible before it expands. that way you'd have more room to turn the bolt more

 

9

95vert354

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Mar 19, 2006

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Jul 17, 2006

#12

• Jul 17, 2006

• #12

If your driving and you think you here it leaking try a down shift and let the motor slow it down ,giving it no gas. Most times if it is an exhaust leak, especially at the header ,you will get a popping or slight backfire through the exhaust. If it does you'll know for sure it's a leak.:SNSign:

 

S

stangz4life

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tampa,fl

Jul 18, 2006

#13

• Jul 18, 2006

• #13

hm i was always told that you should do tighten when hot ..just like header bolts.

 

BlackVert

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Jul 18, 2006

#14

• Jul 18, 2006

• #14

stangz4life said:

hm i was always told that you should do tighten when hot ..just like header bolts.

Click to expand...

you're probably right, it just seems to make more sense to me the other way ...

 

1TallMF

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Apr 17, 2006

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Montreal

Jul 18, 2006

#15

• Jul 18, 2006

• #15

I was thinking cold makes more sense too, but I have heard the old tighten-when-hot ritual. Seems to me if you tighten when hot, it will just shrink as it cools down, decreasing the tightness

 

94-302-vert

Active Member

Aug 16, 2004

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Jul 19, 2006

#16

• Jul 19, 2006

• #16

I belive in retighten when hot...

Ever notice that the oil filter comes of 100 times easier if the engine is warm?

Heat allows the clearance btween the bolt and head to topen up, plus the bolt grows in length allowing more room to tighten...

 

BlackVert

15 Year Member

Oct 3, 2003

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Jul 19, 2006

#17

• Jul 19, 2006

• #17

yeah ... that makes sense ... i guess ... the block expands more than the bolts so the holes are bigger ... making it easier to get the bolts in farther ...

 

VibrantRedGT

"STANGNET'S PENGUIN SMACKER"

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Boca Raton, Florida

Jul 19, 2006

#18

• Jul 19, 2006

• #18

Paul, does it make the sound in neutral too (no load)? Exhaust leaks if bad are usually constant. Under a load more vocal obviously. I was trying to rule out detonation. Ticking noises in hot conditions under load could be lifters, exhaust, detonation, injector, etc. Need to rule out a couple of these.