Exhaust repair 08 OB

[brus brother]

Heard a small puffing exhaust leak on my 08 OB. It appears the source was inside a shroud at the y junction behind the rear cat where it splits to the 2 rear mufflers. Cost of the piece which contains the rear cat and the pipe is around $400. Local welder said for $150 minimum he would remove the shroud (there is one on top and one below} that protects/fortifies the Y joint and try to weld it. He was complimentary of Subaru exhaust metal and said he might be successful.

Furnace repair tech gave me high temp (500 deg) bright red silicone sealant in a caulking tube with a long nozzle. I was able to inject into the crotch area without removing the shroud and while the metal wasn't clean, it seems to have done the trick... for now. The price was right! I'm going to keep the sealant next to my duct tape for emergency repairs.

[Rooster2]

The shrouds are only for fire protection should you ever park in high dry weeds. With me, this never happens. So, IMO, I have removed shrouds and never replaced them when having exhaust work done. Your caulking may work for a while, but I would recommend going to a mom and pop type muffler shop, the kind that does torch pipe cutting, new pipe bending, and welding on of new pipe. For this type of repair, they would charge around $50, maybe less,  to simply replace the piece of bad pipe, or weld to cover the leak.

 

Don't waste your time trying to get this type of work done at the dealer, or any of the chain muffler shops. They all want to throw on expensive parts to fix the problem as in your $400 quote. You don't need to be replacing cats or mufflers.

[brus brother]

Agreed on the heat shields though Smokey the Bear might disagree.

In my case however, shroud might not have been the best terminology. As you can see, it's more of a brace/support at a Y junction behind the rear cat. As it is, there appears to have been a crack at the "crotch" of the Y and I don’t think it wants to be any less supported by removing the brace.

[brus brother]

Agreed on the heat shields though Smokey the Bear might disagree.

In my case however, shroud might not have been the best terminology. As you can see, it's more of a brace/support at a Y junction behind the rear cat. As it is, there appears to have been a crack at the "crotch" of the Y and I don’t think it wants to be any less supported by removing the brace.

Edited October 21, 2014 by brus brother

[Rooster2]

Yea, I now see what you mean. It is not a weed shroud, but a welded on brace to stabilize the pipes as one splits into two. IMO creating dual exhaust by splitting a pipe into two is all for "show," and does nothing for performance. If the car were mine, I would consider having a Mom & Pop muffler shop (like I described in a previous response) cut the pipe off at the "Y", then convert the exhaust system over to become a single pipe running back to the bumper. It would be the easiest solution. There is nothing illegal about doing this. All exhaust emission systems would remain in place.

[brus brother]

Yea, I now see what you mean. It is not a weed shroud, but a welded on brace to stabilize the pipes as one splits into two. IMO creating dual exhaust by splitting a pipe into two is all for "show," and does nothing for performance. If the car were mine, I would consider having a Mom & Pop muffler shop (like I described in a previous response) cut the pipe off at the "Y", then convert the exhaust system over to become a single pipe running back to the bumper. It would be the easiest solution. There is nothing illegal about doing this. All exhaust emission systems would remain in place.

Agreed but then I would lose the Vrooom Boy Racer look!

In the current configuration the pipe splits and then goes to two mufflers before it reaches the bumper.

So, for now the $5 tube of 500 degree high temp silicone is working and since the defect was just a crack in the weld at the crotch of the Y it seems structurally sound, not relying on the caulk for integrity.  I gooped in a couple of layers of silicone, allowing to dry between applications, hoping to get an additive sealing effect since I was unable to really clean the surface of the crack. If it fails, not much has been lost. There's more silicone left in the tube!

[Rooster2]

Agreed but then I would lose the Vrooom Boy Racer look!

In the current configuration the pipe splits and then goes to two mufflers before it reaches the bumper.

So, for now the $5 tube of 500 degree high temp silicone is working and since the defect was just a crack in the weld at the crotch of the Y it seems structurally sound, not relying on the caulk for integrity.  I gooped in a couple of layers of silicone, allowing to dry between applications, hoping to get an additive sealing effect since I was unable to really clean the surface of the crack. If it fails, not much has been lost. There's more silicone left in the tube!

Instead of using high temp silicone as a patch, I would suggest using JB Weld. However, it may be too late to use JB, as it requires super clean surfaces to bond to the steel of the exhaust pipe. Don't know if you could ever clean off the silicone well enough to get JB Weld to bond.

 

You could still go to the single pipe fix. Just keep the unused pipe attached to your car for the visual Boy Racer look. Only in situations where water vapor is seen coming from the exhaust pipe, would it look odd. Vapor coming from one pipe, and not the other.

[brus brother]

Instead of using high temp silicone as a patch, I would suggest using JB Weld. However, it may be too late to use JB, as it requires super clean surfaces to bond to the steel of the exhaust pipe. Don't know if you could ever clean off the silicone well enough to get JB Weld to bond.

 

You could still go to the single pipe fix. Just keep the unused pipe attached to your car for the visual Boy Racer look. Only in situations where water vapor is seen coming from the exhaust pipe, would it look odd. Vapor coming from one pipe, and not the other.

Well, since it was impossible to access and super clean the area for JB or anything for that matter (hindsight I guess I could have sandblasted the area) I am counting on the tenacity of the silicone to bond to the adjacent rusty exhaust pipe and seal the crack. I extended the silicone beyond the thin crack and am hoping that the flexibility of the silicone might work to my advantage.

If the bandage fails, I will arrange for a buddy with a lift to cut open the bottom brace enough to get rid of the silicone and weld the crack.

Likely, this methodology will not make it to the Subaru Repair Manual section of the site. I was just glad that there was a high temp silicone to try out.