Header Leak?
Thread Starter
Racer
Joined: Jul 2008
Posts: 250
Likes: 6
Header Leak?
First off here is what I have. 1981 Automatic with properly working CCC system. No codes. All clear.
I have Flowtech long tube headers and a true dual exhaust. My passenger side has ALWAYS had a leak. I even replaced the headers that were on it with the flowtechs and I have the same leak. It's driving me nuts. I have even used double gaskets and there is no change whatsoever. I know its leaking from the bottom of the header because I used seafoam to make sure it was leaking...I figured that was the best way for me to see if it was really leaking. There is a temp switch on that side of the engine that the header is very close to but it doesn't look like its touching. Is it possible that this could be my issue or does anyone out the have any ideas that might help me?
I have Flowtech long tube headers and a true dual exhaust. My passenger side has ALWAYS had a leak. I even replaced the headers that were on it with the flowtechs and I have the same leak. It's driving me nuts. I have even used double gaskets and there is no change whatsoever. I know its leaking from the bottom of the header because I used seafoam to make sure it was leaking...I figured that was the best way for me to see if it was really leaking. There is a temp switch on that side of the engine that the header is very close to but it doesn't look like its touching. Is it possible that this could be my issue or does anyone out the have any ideas that might help me?
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
I learned this 35 years ago. Use stock exhaust manifold gaskets on your headers!!! With the stainless steal perforated gaskets, they seal every time and they never blow out. If it loosens up and a leak appears, just re tighten!
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
If it's your collector gasket, it's even easier!
With new or very good condition collectors, use NO gasket! Just snug the bolts without killing it causing warpage to the flanges and double bolt or loctite it good
You may have a tiny bit of leakage when it's cold but within 2-3 minutes the heat expansion will seal the collector
With new or very good condition collectors, use NO gasket! Just snug the bolts without killing it causing warpage to the flanges and double bolt or loctite it good
You may have a tiny bit of leakage when it's cold but within 2-3 minutes the heat expansion will seal the collector
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
I re read your post and just wanted to point out that your header might be hitting something? Make sure it's not bumping up against the starter or a knock sensor.... Anything that can keep that flange from laying flat against the head. They won't bend!!! In some rare cases I've seen guy cut the header flange in between each exhaust port.
Thread Starter
Racer
Joined: Jul 2008
Posts: 250
Likes: 6
I have thought about separating them by cutting most of the material between the ports. That would also leave room for the temp sensor. Everything else seals up great with no issues...driver's side, collectors, everything. It just sounds bad (to me). I like the idea of using the regular manifold gaskets as I have never tried that before.
Safety Car
Joined: Jan 2009
Posts: 3,736
Likes: 56
From: anchorage ak
First off here is what I have. 1981 Automatic with properly working CCC system. No codes. All clear.
I have Flowtech long tube headers and a true dual exhaust. My passenger side has ALWAYS had a leak. I even replaced the headers that were on it with the flowtechs and I have the same leak. It's driving me nuts. I have even used double gaskets and there is no change whatsoever. I know its leaking from the bottom of the header because I used seafoam to make sure it was leaking...I figured that was the best way for me to see if it was really leaking. There is a temp switch on that side of the engine that the header is very close to but it doesn't look like its touching. Is it possible that this could be my issue or does anyone out the have any ideas that might help me?
I have Flowtech long tube headers and a true dual exhaust. My passenger side has ALWAYS had a leak. I even replaced the headers that were on it with the flowtechs and I have the same leak. It's driving me nuts. I have even used double gaskets and there is no change whatsoever. I know its leaking from the bottom of the header because I used seafoam to make sure it was leaking...I figured that was the best way for me to see if it was really leaking. There is a temp switch on that side of the engine that the header is very close to but it doesn't look like its touching. Is it possible that this could be my issue or does anyone out the have any ideas that might help me?
Burning Brakes
Joined: Dec 2010
Posts: 945
Likes: 10
From: Winston Salem NC
I used copper gaskets on mine (Mr. Gasket #7153) with an embossed seal around the ex. port. I also used Stage 8 header bolts and got them really, really tight. No more leaks at the head.
Plus, make sure they are free hanging when you are bolting them up. Not connected at the collector, nothing.
Plus, make sure they are free hanging when you are bolting them up. Not connected at the collector, nothing.
Last edited by jcloving; Mar 20, 2014 at 09:26 AM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
2027 Corvette vs The World: Every Model vs Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
10 Things C8 Corvette Owners Hate (But Won't Tell You)
Joe Kucinski
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!
Brett Foote
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)
Joe Kucinski
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!
Michael S. Palmer
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!
Joe Kucinski
Thread Starter
Racer
Joined: Jul 2008
Posts: 250
Likes: 6
OK, flanges have been cut and header reinstalled with the collector just hanging, tightened it all up and then connected the rest of the exhaust. I will get it on the ground tomorrow and we will see if that does it. As always, very good advice from this forum.