Exhaust leak fix? - Buick Lesabre 02 95k with ticking noise

[BuickGirlFromMars]

11509051 is the bolt part number

 

[BossHog39]

Never said anything about bolt being missing I said because you had the downpipe welded to cat replacing the downpipe with the flex joint is no longer a bolt on application below is a pic from my engine swap 4.5 years ago red square is the flange that bolt to exhaust manifold and right behind this flange is a steel & stainless steel flex joint(as can be seen in my previous post) the inner steel pipe breaks over time and cause exhaust leaks

 

[chibuick]

Yes.
Also since we are on the topic of vibration when accelerating, can you turn your attention to your torque axis mount when on the lift. Its the one near the oil pan (there is a large bracket off the oil pan for it)

View attachment 44673

it should look like this (near the crankshaft)

Also take a look at the trans mount near your radiator(also mounted low and near that circle in your pic) and the trans mount near your driver side wheel. Send pics if you can. There is also one on the subframe (the thing holding the engine and transmission) near the steering rack. If you send pics of them I can tell you any thoughts about them. Its a good thing to check while its in the air.

To remove the front and rear flex-plate dust covers, will I need to remove those cooler lines to the transmission, or is it just a few bolts? The GM instructions didn't specify how to remove the front and rear.

 

[chibuick]

Never said anything about bolt being missing I said because you had the downpipe welded to cat replacing the downpipe with the flex joint is no longer a bolt on application below is a pic from my engine swap 4.5 years ago red squareView attachment 44679 is the flange that bolt to exhaust manifold and right behind this flange is a steel & stainless steel flex joint(as can be seen in my previous post) the inner steel pipe breaks over time and cause exhaust leaks

Thanks, understood, I was talking about a different bolt now for the flex plate front and rear dust covers. Checking the flex joint that you've highlighted here is still on the list to diagnose as well. Thanks!

 

[BossHog39]

Thanks, understood, I was talking about a different bolt now for the flex plate front and rear dust covers. Checking the flex joint that you've highlighted here is still on the list to diagnose as well. Thanks!

if you can get it up to get under there best way to do it is while its still cold that pipe get very hot very quick alone with the cat so while car is cold start it and reach up in there and feel around the flex joint with your hand see if you feel exhaust coming out through the stainless steel braiding I would bet that inside pipe has broken. Or if you have access to a smoke machine run it up tailpipe that would tell you real quick to and if not leaking there it would show you where it is as for the flex plate cover two 10mm bolts remove it

 

[BuickGirlFromMars]

To remove the front and rear flex-plate dust covers, will I need to remove those cooler lines to the transmission, or is it just a few bolts? The GM instructions didn't specify how to remove the front and rear.View attachment 44680

There is a single push pin that holds the lines to the same place
the big circle is the pin you need to remove to move the cooler lines out of the way, the pin is removed by raising the head of the pin (small red circle) with a trim removal tool or a flat head screw driver. once that is pulled out, the other end of the pin collapses so it slides out. It kinda works like the pins which retain the wheel well covers.
this is smaller but it shows how it works

Then you can pull the covers out of the way from behind it.

 

[chibuick]

Hope you all had a great Thanksgiving - I still have not been able to check on this. Just got some new jack stands but will also need to buy a floor jack or wait on my friend to use his, but not sure when he'll be available. I also don't have a flat paved place to work on the car unless I use my friend's garage. This part sucks about living in an apartment with no parking.

Might be a while before I post an update, unless Home Depot will let me jack the car up in their parking lot if I buy my floor jack there? lol. Getting cold here though, might be rough in the winter.

 

[chibuick]

I was able to jack the car up today and grab some pictures of the flex plate with the dust cover off. I went for a test drive without the cover and the noise persists, so thinking this must be the exhaust flange bosshog39 pointed out earlier. I got some pics of that too and noticed it doesn’t seem I have that same steel/stainless steel flex joint. Looks solid to me - maybe that’s the cause of the noise? What do you guys think? Thanks.

 

[BuickGirlFromMars]

i dont see any issue with your flex plate from what i can see either. buick stopped using a flex pipe on 2000+ park avenues and thus all lesabres didnt have them either

Its possible yours isnt in good shape or that the flange to the manifold isnt properly sealed/connected, but id like to know what your exhaust hangers are looking like at this time? Swung forward, back, or straight down?

 

[chibuick]

does this help?

 

[BuickGirlFromMars]

does this help?

hmm. those all appear normal.
There is a heat shield that covers the steering rack between the exhaust and the rack, is that tight

 

[chibuick]

hmm. those all appear normal.
There is a heat shield that covers the steering rack between the exhaust and the rack, is that tight

I'll take a look at that once I jack it back up this week. Thanks for all your responses for this!

 

[chibuick]

Update:

Had a mechanic smoke test the exhaust system and saw nothing come out, but he definitely heard the clicking while driving so I'm not crazy. He used his stethoscope and said he could hear a leak coming from this phalange but could not get smoke to come out of it. He thinks it's such a small leak but gets exacerbated when driving the car (I only hear it when the car is accelerating and moving 10mph+ approx).

So, he recommended leave as is until the leak gets worse and we can detect via smoke, but that the phalange is his best bet.

What do you guys think I should do, and if I wanted to replace that phalange / pipe would I just use the part# from the image BGFM shared #52270 and have a shop bolt/weld on for me? Thanks!

 

[BuickGirlFromMars]

Update:

Had a mechanic smoke test the exhaust system and saw nothing come out, but he definitely heard the clicking while driving so I'm not crazy. He used his stethoscope and said he could hear a leak coming from this phalange but could not get smoke to come out of it. He thinks it's such a small leak but gets exacerbated when driving the car (I only hear it when the car is accelerating and moving 10mph+ approx).

So, he recommended leave as is until the leak gets worse and we can detect via smoke, but that the phalange is his best bet.

What do you guys think I should do, and if I wanted to replace that phalange / pipe would I just use the part# from the image BGFM shared #52270 and have a shop bolt/weld on for me? Thanks!View attachment 46852

send pics of your exhaust hangers

and clicking in that area could be more than just there, it could also be the heat shield above the cat

It could also be other things, and if he heard it by probing the floor im inclined to think it could be the cradle the engine assembly

Do you have a socket and big breaker bar or impact? Iwould loosen the subframe ever so slightly, and retighten to spec to see if it changed anything. Also the transmission mount being shimmed is a verified repair in at least 2005 models for the same issue

 

[BuickGirlFromMars]

power steering lines could be smacking too

 

[chibuick]

Hey BGFM, I think I posted pics of the exhaust hangers in a previous post here and you mentioned all looked ok. The mechanic heard the leak coming from that flange while the car was in the air and he was under, but he couldn't get smoke to come out of it.

The clicking is directly proportional in volume and speed with my throttle, so it really sounds like an exhaust leak to me. The fastest I accelerate the faster it clicks, and disappears the instant I let off the throttle even if I'm coasting. I'm not sure what the cradle/engine assembly is nor about the transmission mount or PS lines.

 

[BuickGirlFromMars]

Hey BGFM, I think I posted pics of the exhaust hangers in a previous post here and you mentioned all looked ok. The mechanic heard the leak coming from that flange while the car was in the air and he was under, but he couldn't get smoke to come out of it.

The clicking is directly proportional in volume and speed with my throttle, so it really sounds like an exhaust leak to me. The fastest I accelerate the faster it clicks, and disappears the instant I let off the throttle even if I'm coasting. I'm not sure what the cradle/engine assembly is nor about the transmission mount or PS lines.

then its probably the flange, and you are right on the exhaust hangars lol I forgot this was the same thread I asked that.
The engine craddle mounts, all 6 of them, are responsible for holding your trans/engine to your car. If they were lose or old, the amount of movement that allows could 1) cause a noise 2) cause a ground out that provides the noise you do hear a way to be heard 3) flexes the exhaust more than it is meant to take, causing exhaust leak.

 

[90sbuickrescue]

I'm probably disagreeing with everyone in this thread by writing this, but to me an exhaust "ticking" is coming from a primary tube, not a tube with multiple cylinders fed into it. In other words an exhaust leak at a downpipe flange with all 6 cylinders going through it sounds very different than a blown out gasket on one cylinder between the block and manifold.

I was thinking about this earlier because my parts car that I just pulled the motor out of was ticking when I drove it off the trailer, as soon as it warmed up it went away though. Like in 15 or 20 seconds maybe. It's going to really irritate me if I install that motor without solving this though. I briefly looked it over but didn't see the telltale sign of soot around any of the manifolds or connections. The EGR tube could be doing it too, since that is fed by only one primary tube on the rear manifold.

If you could upload a video to youtube and then link it here, that would make the diagnosing easier too. (Although I have this right in front of me and still haven't solved it. Haha)

 

[chibuick]

Hmmm....so a video of me driving the car so you can audibly hear the leak? It really is only audible while driving the car over 10-15MPH. and with all the windows closed. But if that might be helpful I'll upload it.

 

[90sbuickrescue]

I think mine actually might be the crossover tube, the pipe that connects the manifolds together over the trans. Ticking is not going away now. I guess it's not too difficult or time consuming to pull the throttle body, intake tube etc off and take it apart, but I sure wish I had done that when the motor was out! Annoying.