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Discussion Starter · #1 ·
hi everyone new here. Looking for opinions about an exhaust leak on my 02 ultra. You can hear it when accelerating. I thought it was the mid crossover pipe so I replaced it and no difference. Next I changed the complete egr valve and both egr tubes and no change.Changed the exhaust manifold gasket as well still same.Can't really feel anything down by the flex joint but it's hard to tell for sure. Is there any other places it can have a slight leak other than the things I have changed? Do those factory flex joints really ever cause a problem? Only thing I haven't done yet is replace the complete exhaust manifold and down pipe. Any ideas? thanks in advance
 

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I would get underneath and check the cases of the resonator and muffler. Those are usually the thinnest parts of the factory system.

I'd do that while it's cool, and use an inspection mirror for the top-side, if you don't want to unbolt it to drop it for a full look (the flange bolts can be a rusty pain). If you don't see anything, you can inspect while it's idling to narrow your search. Having the front on ramps, stands, or a lift will make this even easier to check the parts underneath, of course. It shouldn't require revving up to find a leak, so just be careful to check on a cold start and listen for it around various spots.

Good luck, and hopefully you can isolate it for minimal repairs.
 

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Discussion Starter · #3 ·
Thanks man. I will do that tomorrow. It honestly sounds like it's coming from the crossover pipe at the rear. I can grab the throttle and give it small revs and the leak seems to be in that area. That said when I changed the complete crossover it didn't change it any. Not louder or quieter. So guessing that must not be it. I even used high temp rtv on all the connections including the egr pipes. It's upsetting cuz this car is so nice. Such a small leak is such a huge pain to find.
 

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Ya, if you think it's engine bay-area after hunting around, you can let it cool all the way down & cold start to stuff your hand around to feel for puffs the first few seconds it's running. You can also try with leather gloves before the temp gets up there, to cover some possible spots until you locate it.

There's a few things I'd personally do to make it simpler, but those tend to be eliminating "extra" parts, so I'll hold off on that.
 

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Discussion Starter · #5 ·
I will try that in the morning. the parts I have put on it really didn't cost me anything because I have several lesabre parts cars I have been pulling from. That's a plus I guess.I just bought this car so don't know much about it other than it only has 90k on it and seems to be well cared for. I think it will be a great car if I can get this figured out.
 

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Rent, borrow or make a homemade smoke machine. Fill the exhaust with smoke and shine a light on the pipes. You should clearly see the leak.
 

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Here is another idea. Engine off plug one exhaust opening with a towel. Duct tape it in place. On the other exhaust opening attach a hose of a Shopvac to it. Make sure the hose is plugged in the exhaust side that it blows air. Use vinyl gloves and tape the Shopvac pipe to the other exhaust outlet. Now put an ounce of dish detergent soap in about 8 oz of water in a spray bottle. Raise car and hold it securely using jack stands or wheel ramps. Turn on the shop vac and spray all parts of the exhaust with the soapy water. When you see bubbles, there is your leak.
 

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Discussion Starter · #8 ·
thanks for the advice. I finally figured it out. I could only hear it inside the car. This was the most stupid thing but here it is. I just happened to notice the big rubber grommet that the shift cable runs through was completely out of the hole. I stuffed it back in the hole in the firewall and went for a drive and dead silent. I must of been just the exhaust and engine noise coming through the hole making it sound like a leak. I worked for a week trying to fix this and all it ended up being was something silly. Crazy
 
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