Possible exhaust leak?

[devvy]

My 95 5.0 has bbk long tube headers, bbk catted x pipe and a pypes catback. ever since i remember it has had this extremely annoying "lawnmowery" sound at low rpms, like a ticking type of sound that gets higher with the rpms. Recently, another sound was added, a little rattle, also heard with raised rpms at around 3k. i dont see anything loose. I've checked for vacuum leaks and i'm fine. I've tightened my exhaust bolts. One thing I noticed is I could feel air coming out of the bottom of the egr, not sure if thats normal or not. I've attached a few clips where you can hear the sound. Any ideas what it could be? I'm extremely tired of hearing it. Any ideas would be appreciated.

Also, for checking exhaust leaks, do I just plug one tailpipe up and run smoke thru the other? Or what's the general way to do it?

 

[GTamas]

Others here are much more experienced than me, but it do sound to me like an exhaust leak. Probably somewhere around the headers? Cylinder head to headers gasket?

 

[ttocs]

best way to check that I know is to remove the headers and look at the gasket. You will see if it has been leaking. Sucks of course esp with long tubes but if you want to be sure put some new ones in while your there and at least you know that is not an issue, or should not be assuming it goes back together correctly

 

[shovel]

Got something that blows air? (shop vac with a blow outlet, electric leaf blower.. ) wait till your car has cooled off and then duct tape it to your tailpipe. depending how powerful your blower is you might need to tape shut the other tailpipe too. No need to do a thorough job of it, even just stuff a sock in or whatever.

Then you can feel for leaks everywhere and take as long as you want and not burn your hands.

There shouldn't be leaks around the EGR tube but it's stainless steel and brittle and people often crack it while removing it. If it's cracked you can tig weld it or have it tig'd by someone - I had mine welded for 20 bucks which I consider a good deal as I'm not able to do that work myself.

 

[devvy]

best way to check that I know is to remove the headers and look at the gasket. You will see if it has been leaking. Sucks of course esp with long tubes but if you want to be sure put some new ones in while your there and at least you know that is not an issue, or should not be assuming it goes back together correctly

I would but I'll have to see if there's a somewhat easy way to do that after I check all my other options. Long tubes were a literal hell to get in there and I am not gonna be doing that again so we'll see.

 

[Daryl]

Worst comes to worst, take it to a muffler shop and have them run an exhaust leak check. That sputtering sound could be coming from any number of places. If it turns out to be the exhaust header gasket, have THEM R&R. They can probably do it without removing the header as long as the old gasket material comes out in 1 piece or can be putty-knifed clean. Then it’s just a matter of sliding the new gasket in, getting one bolt started (I recommend ARP while you’re at it), line it up, get a 2nd bolt started, the remaining bolts will line up and go in.

Not fun at all and definitely a huge hassle, but with 2 guys on it and on a lift, shouldn’t take more than couple hours. Well worth it IMO to let the pro’s tackle it with their equipment, tools and “tricks of the trade”! I’m sure they’ve come across this or similar before and can bang it out, thereby saving you the hassle and headache/stress.

Good luck and keep us posted!

 

[RossA81]

As others have said that sounds like a header gasket leak. Open the hood and lean in and crack the throttle a few times from the throttle body(enough to put some load on it) You should be able to hear if it is coming from one side or the other.

Ross