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BlackNBlue97 09-07-2012 09:55 PM

Exhaust leak?
My 97 TJ 4.0L makes a sputtering sound when climbing a hill at 35-65 MPH. It sounds like exhaust, but the emissions inspection guy said if there was a leak, it wouldn't have passed. Sounds like it is coming from driver side front and "echoing off the pavement." I can't reproduce the sound sitting still and revving. Any ideas?

I've been thinking about a new exhaust to give it a little "throat." Any suggestions for good sounding and efficient exhaust systems. Keep in mind I live in a suburban county which requires annual emissions inspections.

johnxjeep 09-08-2012 06:16 AM

Check up under there and see if your header is cracked.
Mine was making a similar noise and ended up being a cracked exhaust header.

xjcountry 09-08-2012 02:33 PM

Check your exhaust manifold bolts,some tend to break off or even back themselves out especially the very last one,or one closest to firewall. i had a yj that the bolt broke off and a tj that the bolt or stud just coming loose making it sound like an awful exhaust leak.

FlyingMonkey 10-03-2012 11:54 AM

My wifes LJ is doing the same thing and today when I was doing her oil change I hunted it down and 1 of the coupler bolts is missing from the front pipe, connecting pipe to manifold. Been searching online and cant find the bolt size anywhere. Dont want to take 1 of the others out if I dont have to since its kind of a pain to get to them with the cats in the way. Anyone know the bolt size by chance?

Maverick906 10-03-2012 01:28 PM

My sister recently bought a jeep with an exhaust leak. Turned out to be the weld around the O2 sensor behind the cat failed. As for brand of new exhaust, Flowmaster 40 sounds great around town but on the highway at high rpms it sounds a little ricey.

shatteredsoul 10-03-2012 04:11 PM

Monkey, have a look at part # 03127 on Advanced auto. The bolt should be 3/8"x 1 3/14".

Also the 4.0 exhaust manifolds are notorious for getting cracks around the welds. Mine sounded like a small lifter tick/peck under load and was cracked almost all the way around the collector.

JBTJ 10-03-2012 04:14 PM

With the engine running, dribble some ATF down the throttle body, may have to keep the RPM's up a bit. It will smoke like hell but it will show you a leak if you have one.

FlyingMonkey 10-04-2012 10:05 AM

Put a 3/8-16 x 2" bolt with lock washer and flat washer on it today and leak gone. Was hoping it wasnt a cracked manifold, so i was pleased when the leak was gone. Bolt must have just fell out on her sometime.

shatteredsoul 10-04-2012 02:26 PM

I just realized I typo ,the size should have been 3/4" not 3/14", anyway glad you got her fixed.

FlyingMonkey 10-04-2012 03:08 PM

Yeah I figured it a typo lol, thanks.

Top it off she had thrown a code for the O2 sensor and that has went away after the 5th start since fixing exhaust leak.

The time now is 09:55 PM.

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