I have a '99 F250 Super Duty with the 5.4. I have an exhaust leak and I'm confident it's right at the joint where the up-pipe (Y pipe?) connects onto the back of the exhaust manifold. On the driver's side, for what that's worth. I could hear the air pissing out from that side of the motor and I thought (feared) it was the manifold itself either cracked or the gasket between it and the block.

But then I reached my hand in/around the back of the manifold where it bolts to the up-pipe and I could feel the air jetting out. Couldn't see any damage, however, as luck would have it the air is escaping in between the block and the exhaust.

So. I removed the two bolts/studs that hold the up-pipe to the manifold and am surprised that there is no gasket between the two. Autozone confirms that there shouldn't be. Is that right?

If not, then (unless there is a crack on the manifold that I can't see) I assume the connection just loosened up between the pipe and manifold over time and now it's leaking a little? The remedy then would be to clean both surfaces and bolt it back up?

Thanks in advance,

Jay

 

Correct, no gasket. Just tighten the nuts evenly but don't get crazy. Last thing you want to do is break a stud.

 

Thank you. Quick question: What do you use to screw in the stud/bolt with the rectangular end?

 

The stud into the manifold? It's not supposed to be a rectangle, it should have a head on it to allow the use of a small socket, if I remember correctly.

 

Thanks man. Good point. Just looking at both now and you're right, the busted one I took out has a small hex on it - the ones I got from RockAuto has a rectangle... I'll just wrench em' in.

 

You can use a "shock absorber socket" on the studs with the double D, rectangular, end they come in a couple sizes any auto parts store should have them.