Exhaust leaks at manifold and downpipe joint

[7veloce 0]

I have replaced the gasket but it still leaks at the front (two bolts side) and left side. The flange looks a bit warped. Is there a way to fix this problem without replacing the flange by using a hig-temp sealant?  Any recommendation on sealant/paste?  By the way, this is a stock fed exhaust system with cat. Tom/Coloado

[jonwat 422]

Smothering the gasket with exhaust putty before fitting & then using lock nuts to secure it may work for a while but the vibration will probably crack it eventually.

 

Which flange is warped, the manifold or the down pipe?

 

I think you need to get working with a file to flatten whichever it is.

[7veloce 0]

John,

 

The down pipe flange is warped as far as I can tell.

 

Tom

[7veloce 0]

The master tech person in my local muffler shop told me this morning to use Permatex® Ultra Copper® Maximum Temperature RTV Silicone Gasket Maker. Put the silicone on both side of the gasket and let it dry for 24 hours before putting the gasket on the down pipe.  He told me the Ultra Copper works for him everytime.  Well, I got one from AutoZone will try it after I return from my trip on August 9, if not before.  Will update on my results.

[Vulcan Grey 251]

If your fix doesn't work, the flange can be made flat again, either by machining or flat sanding if not too bad.

[7veloce 0]

Travis,Thank you for sharing your lotus pics.  I see my lagoon blue S1 with Victor's S2 and David's black Countach S.  Tom/Colorado

[Vulcan Grey 251]

Yep, this one.  Hopefully see you again at a cars and coffee when I put mine back together!

[rizla603104 76]

Whilst my issue was with my S4 - I was told that the only way to permanently fix bendy manifold flanges is to machine them. Otherwise you're always fighting with physics - and in the long run you'll be doing it every year.... Also the amount of flexing the manifold does both through heat and engine movement is pretty significant during use.

[7veloce 0]

Whilst my issue was with my S4 - I was told that the only way to permanently fix bendy manifold flanges is to machine them. Otherwise you're always fighting with physics - and in the long run you'll be doing it every year.... Also the amount of flexing the manifold does both through heat and engine movement is pretty significant during use.

 

Yes, I fully agree with you. However, I am going to give a try with the hi-temp Ultra Copper sealer in the morning and see how it work.  I will add a short flexible pipe to deal with the movement issues when I take out the down pipe to fix the flange. Tom

[7veloce 0]

Whilst my issue was with my S4 - I was told that the only way to permanently fix bendy manifold flanges is to machine them. Otherwise you're always fighting with physics - and in the long run you'll be doing it every year.... Also the amount of flexing the manifold does both through heat and engine movement is pretty significant during use.

Greetings from Bishkek, Kyrgyzstan.  I installed the down pipe gasket with Permatex® Ultra Copper® Maximum Temperature RTV Silicone Gasket Maker before I came here. Well,  It worked. The trick is to put the sealer on both sides of the gasket and let it dry for 24 hours before installing. 

Edited July 21, 2013 by 7veloce

[7veloce 0]

Permatex® Ultra Copper® Maximum Temperature RTV Silicone Gasket Maker did not hold up. It leaks again.  I will have to machine top side of the flange to fix it.  Tom/Colorado

[7veloce 0]

Permatex® Ultra Copper® Maximum Temperature RTV Silicone Gasket Maker did not hold up. It leaks again.  I will have to machine top side of the flange to fix it.  Tom/Colorado

I finally got around doing the downpipe and took it in to the machine shop last week.  It looks like I have to cut the pipes that above the flange in order to machine the surface flat.  Do I need to weld them back on afterward? I noticed SJ sports cars UK's downpipe for S1 has just a flat flange with out any short pipes. Any suggestions?   

[7veloce 0]

It worked by cutting off the pipes above the flange, leveled the flange, and bolted back up. Now, my SU AZX 1307 fuel pump is leaking under the front part of the body .  I am not sure what is going on. Took it out this afternoon and will take a look tomorrow.  Any suggestions are welcom.

[7veloce 0]

Replaced the SU fuel pump with a new one. Got thru the Colorado clean air emissions test without any issues. Now, I have a Collector's Plate and only need emissions test every five years. That is great news.

[Anthony Peterson 0]

Leaking flanges are a old problem and still a current problem on any piping system. I created a 2,3 and more bolt fix in my basement after constant leaks in my exhaust system. Once metal fatigue sets in, the force applied to keep flange surfaces mated becomes compromised leading to gases escaping and causing problems. I call my fix a C Flange Bracket.

This is not a spam and not a product available.  Its been on my truck for 2 years.  The best part is not having to weld anything.  An existing flange that is damaged can be removed and replaced with a C Flange Bracket.  Opinions welcomed.

Edited March 10, 2018 by Anthony Peterson
typo