TheOldRaker

I just installed Banks shorty exhaust manifolds on my 07 F150, 5.4 Lariat. I got everything together, and failed emissions during inspection. Ended up tightening the flange bolts a little bit more, where the manifolds attach to the downtubes, and was at least able to pass emissions, but I still have a small exhaust leak. I was smelling exhaust when I used the heater, took it to a shop, and confirmed there was an exhaust leak on the passenger side downtube hookup.

The thing is, where the flange meets, the end of the manifold is crooked from the natural angle of the down tube. Meaning if you look at the flange from the wheel well, it's more closed on the outside, and a wide gap on the side of the engine. It's probably hard to visualize, but if the two flange bolts are front, and back, then the Right side of the flange is toward the wheel well, and the Left side of the flange is toward the engine. The LEFT side of the flange has a gap. It's almost as if the downtube needs to swing in towards the center of the truck in order to look straight into the manifold.

So far I've tried loosening all the Y Pipe fittings, and prying things around, but can't seem to get it to live in the correct place. I also tried jacking up the exhaust with a floor jack, but that didn't really rotate it to where it needs to be either.

Solution? I was looking at possibly just purchasing a stock header, and seeing if that fits. Maybe at least then I'll know if it's the Banks Header, or if it's my downpipe that is crooked.

OR

I purchase a flexible elbow, cut my downtube apart, and install a flexible elbow. Which i'm nervous to do, because it seems like this should just bolt straight together.

Looking forward to hearing what anyone things about this. Thanks in advance for any help here.

TheOldRaker

Well, I decided to try and simply reinstall this thing. The Banks manual says to bolt the header to your head first, so I didn't change that. I did unbolt every connection of the Y Pipe, and bolt the flange from the manifold to the down pipe together first. Then I moved the y pipe back to where it could connect with everything else. I took a test drive, but I wasn't sure if I was still smelling the exhaust or not. Gonna keep a nose on this and report back.

650NutKase

You did install the gaskets before the headers, correct?

TheOldRaker

Yes, the gaskets between the manifold and the heads, yes. That's all fine, no leaks there.

The leak is from the exit of the manifold, into the y pipe. I'm still not positive it's fully sealed.

Also, after posting this, I realized that I probably should have posted in the aftermarket section of the form. Apologies. Feel free to delete this thread if you need to.

dukedkt442

Is it a flat flange connection, or a ball and socket connect? If flat, shouldn't there be a gasket there too? If the flange from the gasket isn't at the exact angle of the factory manifold, yes you'll have a leak. The headers were probably designed to run with their pipes too, not the factory pipes. Loosen the pipe-header connection, and the pipe further downstream (perhaps at the slip-joint downstream of the cat), retighten the header connection, and then tighten the downstream connection.

Danencgso

How did you end up fixing the leaks? I just had new exhaust manifold put on in both sides and now have a small leak in the flange to the Y pipe. I can’t believe that the connection is just flange on flange with no gasket.

CplHicks24

I wondered too about the factory pipes as I am looking at getting a set of these. Good info.