Exhaust Leak
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Exhaust Leak
I have a 1977 F150 4x4 351m.
It has, over time, developed a really loud exhaust leak. I believe that the noise is coming from around the driver's side manifold either where it mounts to the cylinder head or where it attaches to the exhaust pipe.
My question is, what is a good way to isolate an exhaust leak?
I also have a question about exhaust gaskets on these trucks. Where the manifold connects to the exhaust pipe there seems to be a ball/cup type joint. Does this joint require a gasket of any kind or does it just use clamping force alone to seal it? The reason I ask is the parts store doesnt show a gasket to be there.
It has, over time, developed a really loud exhaust leak. I believe that the noise is coming from around the driver's side manifold either where it mounts to the cylinder head or where it attaches to the exhaust pipe.
My question is, what is a good way to isolate an exhaust leak?
I also have a question about exhaust gaskets on these trucks. Where the manifold connects to the exhaust pipe there seems to be a ball/cup type joint. Does this joint require a gasket of any kind or does it just use clamping force alone to seal it? The reason I ask is the parts store doesnt show a gasket to be there.
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I just went through this on my '78 F150...I have the 6.6L 400M. Mine was loud too plus I could smell exhaust in the cab and when standing over the engine bay. It was pretty obvious the gasket was fried. Plus, the state inspector confirmed my suspicion with a big fat rejection sticker...haha
Turns out, the excessive heat also burned up the #8 spark plug and boot.
It took me half a day to get it of, clean it up, and replace it w/ a new gasket and Ultra Copper sealant.
I scratched my head over the ball too but ran into a knowledgable builder at NAPA who assured me no gasket went between the manfold outlet and the exhaust pipe inlet flange.
While I had the manifold off, I did replace the studs on the outlet and used new nuts. I also replaced the 2 studs on the head along with all new bolts to secure my new gasket.
Turns out, the excessive heat also burned up the #8 spark plug and boot.
It took me half a day to get it of, clean it up, and replace it w/ a new gasket and Ultra Copper sealant.
I scratched my head over the ball too but ran into a knowledgable builder at NAPA who assured me no gasket went between the manfold outlet and the exhaust pipe inlet flange.
While I had the manifold off, I did replace the studs on the outlet and used new nuts. I also replaced the 2 studs on the head along with all new bolts to secure my new gasket.
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Yea, i checked my ford parts catalog and it does not show there to be any gasket between the manifold and downpipe. I too am smelling something burning when im driving.
I got under the truck tonight and saw a small wrinkle in the exhaust manifold gasket underneath the manifold where it mates with the cylinder head. I suppose that could be it.
I got under the truck tonight and saw a small wrinkle in the exhaust manifold gasket underneath the manifold where it mates with the cylinder head. I suppose that could be it.
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I too went thru the same thing with my 77,302, and headers. Thought it was between the headers and exhaust pipe, so bought gaskets and bolts and fixed that, but that wasn't the leak. It was left side by the firewall and on the bottom where the headers bolt to the head that the gasket blew out on the bottom side. Not all that hard to replace the gasket and that fixed the issue. Just couldn't see where it was leaking before. Made a heck of a noise though.
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From: Pa
The old piece of hose can help a lot in finding an exhaust leak. I've found leaks by feeling around the flanges with the motor running for leaks also. Best to start with a cold engine using that method though. If you replace gaskets be shure not to bend or otherwise screw them up during the install or you will get a leak.
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Thanks for all the replies.
I replaced the manifold gasket on the side that i thought the noise was coming from. It might have helped just a little, but there is still a really loud exhaust leak. I put a wrench on everything to make sure there wasnt something loose in the system. I hope there isnt a crack in the cylinder head around an exhaust port or something.
I do plan on getting headers and a whole new exhaust system for the truck. I just dont have the money right now as im still in college
I replaced the manifold gasket on the side that i thought the noise was coming from. It might have helped just a little, but there is still a really loud exhaust leak. I put a wrench on everything to make sure there wasnt something loose in the system. I hope there isnt a crack in the cylinder head around an exhaust port or something.
I do plan on getting headers and a whole new exhaust system for the truck. I just dont have the money right now as im still in college
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