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Exhaust woes!

E

ecameron87

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About 10-12 months ago I rebuilt the exhaust on my 72 K5. I installed Hooker headers and Flowmaster Delta 40's. It is dual exhaust with 2-1/2 inch pipe.
As you can guess, I cannot get the headers to stop leaking and it is very loud! I have tried Percy aluminum, copper, cork, paper, and pure silicone for gaskets. It didn't leak when I had manifolds. I am now using OEM original manifold gaskets with "Red" high-temp silicone. This last fix works better, but still leaks.

My question is, what methods do you guys use to find where the leaks are coming from? Does anyone else have any more techniques for leaky headers that I haven't tried?

I have searched the forums and have seen this problem everywhere, but nobody comes back and tells us what cured their leaks.

I am at wits end with this thing and am ready to go back to manifolds unless someone has a miracle cure.
 
Have you checked the headers for warping? I know headers leak fairly easy, but I've found that copper gaskets with [SIZE=-1]some rtv high temp copper sealant fixxes the problem.[/SIZE]
 
Have you checked to see if all the welds on the collectors are fine. I have never had a problem with percy's stuff. I have used them all and they were the only ones that would work on my Mustang GT. I would say that they are warped or they are leaking at a weld before I would say it is the gaskets. Are the bolts staying tight? Stage 8 makes locking header bolts.
Since it is a 72 I would use a gasket buffer and clean up the mounting areas of the header and head since you have had so many gaskets on it.
Just my .02

Erik
 
I always cut away the extra steel btween the exhaust ports so each one will seal individually to the head.I also use stock exhaust manifold gaskets (FEL-PRO)and have never had my headers leak.Good luck!:D
 
I have the felpro stock exhaust manifold gaskets on right now with high temp red silicone on them. I might try cutting the flange up as well. Any other ideas? Anyone know how to find where the leak is coming from?
 
make sure the heads are dead flat and so are the headers, if not then they will always leak. GM makes a stainless steel manifold gasket, it is a 2 or 3 layer gasket and will not rust. I have never had them go bad. Try those because I would not use anything else. Any GM parts guy that knows anything knows about them. Since headers like to come loose use the stage 8 locking header bolts.

If you feel like it isn't the header on the head, check the collectors. Sometimes with collectors when you torque on the engine the collector will separate some and get loud. As far as the rest of the system we always use muffler cement on every seam. Works great and never have problems.
 
Is it leaking from the head area or collector/exhaust pipe area? If by the heads, I ended up having to double the gasket on one side. The only thing I could do to stop leaking was using 2 thick Mr. Gasket header gaskets. High temp and Copper would still leak. Also you must constantly check and tighten the bolts on headers. If you use a gasket sealer use the copper stuff. Tighten the bolts, let the engine get warm and cool then retighten your bolts.
 
ditch the silicone, cut the flanges on either side of the 2 center ports, and you shouldnt have a problem.

O cut here O O cut here O

also, what are you using for bolts?
 
My ramhorn manifolds were cracked so I picked up some used regular ones and some new gaskets.

That was in 93 and I have not touched them since :D

I think the longest lasting fix is manifolds :p:
 
What BeaterK20 said has always worked for me with headers and SBC. And other engines for that matter. and Felpro gaskets.
 
ecameron87 said:
Anyone know how to find where the leak is coming from?
Click to expand...
Stick a hose in your ear and start pointing it at crap. :dunno: Kind of stethoscopic in a way...
 
I am using bolts with 7/16th head and an allen wrench hole in the head as well. I will go ahead and try to cut the flange and use manifold gaskets with no silicone. Thanks for the help.
 
And if your still having probs, PM me and your welcome to swing by my place off Rita Rd. And I'll give you a hand ( or at least a beer )
 
hey man sorry to hear your having problems. my boss has a 4 wheel drive 79 dodge truck with a 440 and he had this same problem. after many gaskets, tubes of hi temp he found out that whenever he really stomped on it the motor toqured so much that one header would hit the frame!! so he put a chain on the motor mount and new gaskets and he fixed it!! also to tell where a leak is coming from look in the general area the leak is coming from and look for carbon build up. a leak that has been there for any amount of time will leave quite a mark. also if you don't see any black run your hand over the exaust about an inch away with the engine running and when you hit the leak you will feel air blowing on your hand be carful don't burn yourself. its best to do this on a cold engine. good luck let us know what fixes it!
 
dude make sure after you change the gaskets that you warm the motor and then re torque the bolts thats what i have done with all my stufff and i also use MR. gasket ultraseal gaskets i never have leaks oh yea i have hooker headers also.
 
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