i have been driving the car every day, and i go through a lot of terrible roads, i figured it may have loosend the nuts on the head. 2 days ago it got louder and now pops a lot on decel. i know this is an exhaust leak, but i checked all the nuts are tight and the ss heats dont move at all, everything seems tight.

What I have done -

Connect shop vac to the tailpipe, using the blow port of the vac. Feel and listen around the heads for rushing air. Makes the job much easier than guessing where the leak is.

This method helped me get my exhaust on with no leaks after several hours of trial and error / frustration.

Edit - It seems plausible that you could blow yourself up if there is gas in the tailpipe and the shop vac motor makes a spark. Be careful. It hasn't killed me yet.

I'd be concerned about blowing debris into the engine past the open exhaust valves ...

Andy

Interesting point. Maybe step zero should be to install charcoal filters in each exhaust port.

Put the motor at TDC for each cylinder before you blow into it. Just used this technique yesterday to solve a EX leak problem.

this is going to sound weird... but i found an easy way was to turn on my engine. the oil burning off the heat exchangers caused small smoking oil, and the exhaust leaks would blow it past in tiny white puffs of smoke! i went "AHA! you sneaky bastard! i found ya!"

Ok, bad joke.

They are fairly audible and can be heard as a pretty audible clacking under the car. I've found cupping my ears, closing my eyes and moving back and forth on a creeper while the car was up on stands was easy to find out where it was leaking out at.

Another useful tip i found on the boards was to wet your hands and feel around next to the exchangers and gasket areas, which is actually very helpful.

It was my car and was very effective.

Use a tad bit of dextron tranny fluid down the intake to use the engine as it's own smoke machine.. Let the engine idle and look for the smoke.

It's difficult to distinguish an exhaust leak from the cooling air blowing past the cylinder heads. Plus when the motor is running, things get hot. The vacuum trick is really handy because it doesn't get hot and there is no cooling air to confuse the issue, and it's QUIET.

Seriously, on Johns car yesterday, once we hooked the blower up to the leaking cylinder there was no doubt whatsoever that we had found the leak. We instantly knew where the problem was and we also knew when it was fixed. So when we finally fired it up, it ran perfectly, just like we knew it would from the test.

Peraps I am missing the point of the vaccume trick. Are you taking the muffler off or just blowing the air up the tail pipe?

Zach

You could do it via the tail pipe, but it's much more effective if you can isolate each cylinder.

I connected the hose right up to the tailpipe. Air went to all cyls, so i could find leaks on all 4 simultaneously!

Interesting. I am convinced that I ahve an exhaust leak on my subaru, that only manifests once the engine is warmed up or under a lot of load. It has not been found with a smoke machine, but I think that is because the engine was not warm when they smoked it.

Zach

Ot but Zach have you seen the jeep nukizer715 one off jeep made?It's in the aug 2010 issue.

On topic, if the suby has the flexible joint that would be the first thing I would suspect if it is a older model.

I have always been able to see the black residue around the leaking joint on the ones I've had to find. The tranny fluid in the intake while it's idling sounds pretty easy except for the cars with o2 sensors and cats. I do like the idea of doing it cold though with the vaccum cleaner or maybe make a adapter and use compressed air, maybe you could warm it up first if it's heat related. A small piece of pvc held to the ear will make a good listening device to keep your head away from hot or oily parts also.

At idle, have someone hold a piece of cardboard or a block of wood on the end of the exhaust to parcially block exhaust. It might make the leak more pronounced and easier to find. I haven't really tried this but a watched an old guy in a muffler shop do it with some success.

I have been doing this for years!! I put a rag over the pipe and block it off. If there are leaks you will hear them and the car will continue running. If there are no leaks it will begin to die!

pretty sure it is comming from the passenger rear exhaust port. this is the port that was not flat oval shape. it had a high spot on the head so i used a die grinder and very gently tried to even it out. it is still a little high on that side, but i am nervous as shit to keep grinding in my head since the car is currently running.

i guess i should just live with it, im tired of breaking things, i just wanna keep driving. i also think it increased when i mis adjusted the valves on 2 cilinders. i will fix that tommorow, and mabey it will be less noticable. does that make sense
??

I watched a muffler be welded on with a torch. He then checked for leaks by running the torch around the welds. The flame burned yellow where there was a leak, if I remember correctly. Of course that may not be safe that close to the engine block?

If it was still a little high, I can promise you that is where your leak is.
Readjust your valves, and live with it.
You have a 2056 that needs building.
I will pester you about it until you build it, so you may as well start now.

Zach

That's a killer idea! You could eliminate the issue of blowing crap by the open exhaust valves by simply doing the opposite and applying vacuum to the tail pipe. If necessary, a little smoke could tell you right where the leak was.

well...

IT GOT EVEN LOUDER TODAY

i found it

that is the bottom of a bursh "High flow " muffler. It was purchased brand new last fall.

Wow.

I do drive a little spirited but ... Wow

If that was truly a new muffler last fall, I would be returning that puppy for a replacement.