The Old Car Files: Exhaust Hole

 This is the first in what I expect is going to be a recurring topic.  Today's post is brought to you by my 2003 Honda Element which I purchased used in 2006. 

When I was a kid, I heard that a car is considered antique when it reaches 20 years old. Cars have improved their quality and longevity since then.  Nowadays, based on my sampling of Google results, it seems ~25 years old is the threshold for considering a car a classic and ~40 years for an antique.  This car has spent it's 19 years in New England.  Winter snow and road salt is harsh on vehicles causing them to deteriorate faster than they would in say, Southern California.  New England car years are like dog years, so by that measure, my E is a New England antique!

While the E is old, it is still in pretty good shape and only has about 100K miles. Because there is no currently available vehicle that is its equivalent in terms of versatility and practicality, I'm determined to keep it on the road and do as much of the work on it myself for fun and learning.  I have no mechanic experience, so I'm learning as I go.  [Flex alert! 💪] Over the past eight years I have replaced the front control arms, shocks, rear brake rotors/calipers, radiator, water pump, belt tensioner, tie rod ends, rear sway bar bushings and repaired a muffler flange and saved many thousands of dollars doing all the work myself with aftermarket parts. I tried to do my own alignment after the tie rod end replacement but couldn't get it dialed in properly.  I had to take it to a mechanic so it could be aligned via machine [Flex fail 😥]

For the past few months, I'd been noticing an exhaust smell in the cabin when I was at stoplights.  At first, I thought it was just exhaust coming in through the rear moonroof which I usually keep cracked open during the summer.  But the problem continued into the Fall after I closed the moonroof, so I started to suspect I had an exhaust leak somewhere.  An initial check of the exhaust covering what I could see and feel under the car without pulling out tools didn't turn up any leaks.  I procrastinated some more.  I finally had enough free time to dig into it this weekend.  

I pulled the header cover off and inspected the headers as best I could.  I had about 30 seconds to look for a leak from when I turned on the car until the headers were hot enough to burn me.  I didn't see or feel any obvious leak.  

Learn from my mistakes tip- after I had already risked burning myself and was researching how to fix my problem, I saw a neat trick in a Youtube video:  Hook a shop vac set to blow to the exhaust pipe (with the car off, obviously).  You can then feel for leaks or spray soapy water and look for bubbles without risking burning yourself!

Next, I jacked up the car and put some jack stands underneath it.  I turned on the motor again and climbed under and felt around for the leak and found it this time.  Exhaust was escaping around a shield on the down pipe between the header flange and the catalytic converter.  That's a good news / bad news situation.  The good news is I wouldn't have to deal with the rusty bolts on the header and risk snapping one off in the engine block.  The bad news is a catalytic converter is expensive to replace, so I was going to have to come up with an alternative fix plan.  I don't have a welder... yet... so the obvious solution of welding a plate over the hole was out.

I pre-emptively ordered this stuff as soon as I found the hole with same day delivery from Amazon [commission earning link]:

 

Then I set to work cutting off the welded-on shielding so I could access the hole to patch it.  As car repairs typically go, this was easier said than done.  I was on my back on a creeper barely able to squeeze under the car on the jack stands and there was no room to maneuver an angle grinder with cutoff wheel.  The flange bolts holding the cat and exhaust in were very rusted and would have to be cut off, so dropping the exhaust out of the car would require replacing all those bolts and a couple gaskets and I didn't want to spend that money if I didn't have to.  So, I used an oscillating multi-tool with metal cutting blade and was finally able to cut the two side welds securing the shield to the pipe.  It still didn't come loose.  It turns out they welded the center of the shield to the pipe as well, right in the area where the leak was coming from.  I was able to pry it off, but it pulled out a nickel sized piece of rusted tube with it, so now there was a big hole in the exhaust.  The JB Weld crack sealer wasn't going to fix that.  Interestingly, this exhaust tube leading to the cat was double-walled.  That probably explains why the original hole wasn't obviously loud like most holes in exhaust systems.

Back to the Internet for more research.  I found another JB Weld product that could handle the high temps around the header [commission link]:

   

My local O'Reilly had this in stock, so I ran out and got this so I could put my car back together tomorrow before I needed it for work on Monday.

The hardest part was next.  I needed to grind down the welds so the wrap would go tightly around the pipe.  The angle grinder would've made quick work of this, but since I couldn't get it in there, I struggled with a rotary grinder, the oscillating multi-tool and hand file.  My safety glasses kept fogging up so I couldn't see.  My arms were killing me from having to work at awkward angles above my head.  I was covered in rust debris from the grinding and other rusted out bits under the car.  After an hour or so, I had them ground down good enough for my standards.  I used a wire wheel to clean up the pipe as much as possible in preparation for the wrap.

Here is a photo of the hole and cleaned up pipe ready for wrapping. 

The exhaust wrap went on fairly easily, though it was a little shorter than I would like.  I couldn't get as many wraps over the hole as the instructions recommended.  I used a heat gun to cure it a bit and then turned the engine on and idled for 20 minutes to heat cure it further.  I then went out for a twenty-minute drive to pick up a Powerball ticket for the $1.9B estimated jackpot to raise the exhaust temperature further and finish curing the patch.  

Even if I don't win the Powerball, I at least beat the exhaust hole.  The patch held perfectly, and the exhaust leak was gone.  We'll see how long it lasts.