Long story short, I've had my exhaust tightened up by 3 different people. Today I had a muffler shop do it and use red locktite on all of the bolts. Within 40 miles of driving, I heard it starting to come loose again.

It's been loose at the manifold, the bottom of the cats, and where the mufflers bolt on. The exhaust is bolted together with two-bolt flanges with a gasket. (Injen SES with Ark Resonated HFCs)

Since the exhaust is all stainless, the muffler shop didn't want to or couldn't weld it. So what's my next step? Do I need to find someone who can weld stainless? Should I have a shop just put a tac weld on the bolt and nut? Why is this happening?

 

get some lock washers... problem should be solved at that point

 

+1 Stage8

 

So do I use a lock washer under the nut with a stage 8 bolt?

If so, what are the best lock washers to get?

Does stage 8 make long enough bolts? I think they need to be 50 or 60 mm...

 

Lock washer, cotter nut or crush washer.

Just fyi Red lock tite is strong until heat is applied. That's what makes the red compound, well the red compound, it's meant to fail as soon as heat is applied for removal...

Exhaust is a high heat area so using red is useless.

 

Double nut? Grade 8 bolts can be found at home depot/lowes for a few bucks. I used to use them all the time for exhausts. Grade 5 would work also

 

Lock washer will solve the problem

 

use existing hardware, just add lock washer

 

+1 what he said!

 

Sorry for asking to be spoon fed here guys, but I really don't want to have to deal with my exhaust coming loose another 3 times. It would be nice to enjoy a properly performing car for more than an hour.

So what style of lock washer do I use? Link would be great. I've read the ones that work on spring principle don't last due to being heated up and cooling down over and over, but I've only found that in one place.

Also, should I just put the washer on the nut side, or the bolt head side as well?

 

So I guess a split washer is as good as any other.
Another potential problem I noticed. The bottom of the driver side cat seems to angled upward slightly. So the mating pipe flange doesn't want to naturally be flush with it. It can be forced into place and bolted together though, but this seems to be the first joint that comes loose.

Is this angle semi-normal or does this indicate a problem with installation or with the part itself?

 

Not all parts are designed to work with eachother.
Lock washers should have solved the issue

 

I don't think any exhaust system would line up straight on with the cat. It's angled up toward the car. Even the exhaust from ARK isn't angled down to meet the cat.

I'm thinking of getting 60 mm bolts, using a split washer, two nuts, and then slightly deforming the bolt thread just for overkill. I'm just curious if I should be complaining to ARK about the angle of the flange or if things just sometimes work out this way with the angle, or if this likely means the cat wasn't installed properly.

 

this

 

Are you guys talking about split washers when you mention lock washers?

 

Well, lock washer or not, this doesn't address the problem entirely. And I would, with a high degree of certainty, guess that the crooked cat is the cause of all your problems.

Think about it.... hot/cold cycling, vibration from exhaust/engine, torque over from engine/trans twisting the exhaust, I mean, what more abusive environment would there need to be to loosen/crack/break a pipe? Add to that a malformed exhaust junction, or course something's gotta give!

Hell yes, I'd complain to the maker of that cat. It's obviously junk if it doesn't allow the Y-Pipe to mate up EXACTLY where it should be.

Proper fit exhaust systems should NOT require lock nuts to keep them tight.

IOW, junk that sh*t and get yourself some Berks.

 

It's coming loose in spots other than that junction as well, but that does seem to be the first place it loosens up.

ARK isn't known for junk and is pretty expensive, that's why I'm hesitant to blame that cats. Installation seems pretty damn simple, but is there anyway it could be culprit here?

I'll try to get pictures later this week.

 

I called it junk because of what it's doing, not whether they are known as a junk dealer or not. It is either the wrong cat or it's a manufacturer defect.

And, yes, it could.

 

So I emailed ARK last night with these pics. Anxious to see what their reply is.

 

Update: So since I needed a retune due to it being initially tuned with an exhaust leak, I had the shop also tighten the exhaust. I went a bit overkill with the hardware, but it now seems to be holding just fine.

I used: flange bolts, washer, lock washer, flange nut, and lock nut.