2009 C2S 164K miles

A few weeks ago, I was down in Cape May NJ .... got in my car to come home and the car sounded very different. It sounds like I cracked a header, muffler or something. The sound is like a smoooth truck. It is not real loud but yes, it is louder. I can even hear the burbling when coasting and just, ever so slightly, touch the gas. I definitely did not hit anything. It is coming from the driver's side but not obvious where it is. It does get louder when heated up, but not by much.

Question: How do I diagnose where the problem is?

I have the Sharkwerks cross pipe, and a few weeks before this happened, I had the muffler off to do my spark plugs. So, I thought it was the clamps that attach the muffler to the cross pipe... I just went under and tightened them up. No difference. So, I thought one or two of the bolts that hold the Sharkerks muffler to the catalytic converters sheared... those infamous three evil bolts.... so I ordered new bolts and a new gasket just for the heck of it.... for both sides since I am in there... about $50 total so no biggie. So I did an oil change today and with the car jacked up, the three evil cat bolts look fine. They are rotted, but look like they held. When I did the Sharkworks pipe many years ago, some bolts broke others did not so I replaced only the broken ones. The headers look fine from what I can see laying on my back... of course I can't see everything. I think I have to pull the bumper and mufflers off to really get the best view.

Advice?

Peace
Bruce in Philly

 

Gaskets? Throw it up on jack stands and start it up. See if you can find where it’s coming from. Might have just “blown a gasket”.

 

Usually exhaust leaks are pretty loud but you most likely have a simple exhaust leak or maybe a cracked weld somewhere. on a lift it will be very obvious.

 

If it gets louder when the car warms up, I’d suspect a crack somewhere. My guess is a header.

 

Fabspeed makes the best exhaust gaskets. I keep a couple sets in the cabinet for whenever I have to remove a header or muffler to do something. Put things back together with stainless bolts and copper flanged lock nuts and use some anti seize on the threads. The oblong nuts will hold even with the anti seize and you'll ge able to get them apart again.

If you have factory mufflers, they're not stainless steel like the aftermarket ones are. With the mileage on your car and using it year round in PA where there's snow and salt, I'm guessing you have a rusted pinhole in one of them. If the sound is rattly and not poppy or puffy sounding, that's more likely in the cats where the wraps are fracturing inside and vibrating.

 

2009 C2S 164K miles

Found the exhaust leak... a bracket weld broke from the pipe but oddly, there is a perfect hole underneath. Why? This is not a rust hole. Did Porsche have a hole for a bolt and then decide welding was better?

I purchased new brackets to attach the muffler to the center pipe as I discovered it was blowing a ton of air..... so when I disassembled everything, I saw the crack and the big soot marks.

Tough finding a welding shop... Bavarian in King of Prussia could not do it until Monday but they referred me to a guy in Media who will do it tomorrow morning for me... yeeehaa!!

Oh, and I replaced that rotting heat shield I found when I did my plugs. Occasionally I would hear a buzz back there and I thought it was the heat shield but it most likely was the broken weld. I had to remove the ignition coils to get out the shield. Those heat shields are actually two layers of aluminum.... I wonder why it was engineered this way?

Very fiddly but it was cool because I spitted out some new cuss words. No, these weren't old unused cuss words but brand new to me. I found when I get really angry and frustrated working on my car, I start speaking in tongues.... apparently the ancient language I channel are rare cuss words used today. I love working on my car.

Peace
Bruce in Philly

 

Can't tell for sure Bruce, but it looks like it broke (including the hole) right along the weld line. And from your other post - I had a frog like that in 7th grade Biology class all staked out on the board.

 

Actually think mine is separated in the exact spot but don’t recall a hole. Will look at it over the weekend. Been meaning to fix it but haven’t gotten around it.

 

Call Rick!

 

Here is the weld work.

Brad Fab in Media PA. Highly regarded by Bavarian, a BMW shop.

Interesting, Steve noted that the hole is common... not caused by rot... something about how it was welded and use of mid-grade, thin stainless tubes. The weld somehow interacts with the tube and... well, the weld did not crack.... the tube cracked along the weld line. Weird. That hole you see is exactly the shape of the original weld... plus there was a creeping crack I was not aware of.

Lesson: If your weld cracks, you probably have a hole too.

Steve didn't weld it the way I would have thought. First he cut the bracket near the crack then used the small section of the bracket as a patch over the hole and welded all around. Then removed and re-welded the good bracket, then welded the two ends of the bracket together. $125. And he let me put on a welder's shade and I watched him weld up close. He said "get in here if want to see anything". Coool.

Peace
Bruce in Philly

 

Well it is all repaired and the car is put back together..... boy is this thing quiet.... I kinda miss the noise.

Peace
Bruce in Philly

 

Glad it worked out and it's all back together

 

A drill can always fix that...

 

Update 1.5 years later.

Well.... getting more exhaust noise. So I figured the other muffler now failed. Nope... same muffler. The noise is not too bad, but She doesn't like it when I pull into the garage. So.... My new next door neighbor restores cars! Wow, great luck, and he has a MIG welder. He said he will not help me, but he would TEACH me! Wooohooo!!!! I got to swing a big, stiff welding hose. Yea! I never welded before... this is gonna be great!

So I pulled the muffler and discovered a weld done by the pro welder noted above, cracked. I don't know why... anyone?

My neighbor showed me how to weld on some 22 gauge panel metal from an old VW. With a wire brush on a drill, I polished off the paint, then set up the welder, then went to it. Now we hoisted my muffler up on to the welding table where I took a grinder and cut the weld line so I could go deep and hit the pipe and hole under there. Then I started to weld.

Boy do I suck. That is OK, my neighbor made sure I got good penetration and went slowly. No pulling or pushing, I just made a row of "dimes", 1-2 second bursts. Then went back over and hit some missed spots. The weld I did looks like pure hell... but I don't care, I got to weld, something I never did before, and repaired my car for free. No one will see this mess, but it sure looked like it worked. I hit it with some black, high temp paint.

Will it crack like the pro's work? Time will tell.

Peace
Bruce in Philly (now Atlanta)

 

Those welds aren't "stack of dimes"