exhaust leak under load

[guitardude2007]

my 1997 ranger 4.0l has an exhaust leak that ive been having trouble finding. it will only do it under load and not at idle or when revving in neutral. I have replaced both manifolds, gaskets, egr and egr to manifold pipe due to the old manifolds being rusted out/ cracked. everything is torqued. I have tried putting a rag in the tail pipe still cant find it. haven't had the chance to use a smoke machine on it yet. is there anything common on these engines to check for? I don't see any soot or anything anywhere. seems to be leaking from drivers side somewhere around the manifold area or at least that's what it sounds like when driving. this has done it even after replacing those parts. the egr valve seems to have a small crack where the fitting for the tube goes in but it is very small. maybe it could be there? I'm planning on replacing the valve anyways. hopefully someone has had this issue before and knows what it is because its really starting to get annoying. thanks in advance.

 

[WarHawk-AVG]

The bushing donut where exhaust manifold to the exhaust pipe going to cats and muffler?

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[guitardude2007]

nope doesn't seem to be. rechecked torque, listened with a scope/ hose and checked for soot nothing found. I even checked all the way back to the muffler everything is welded and no leaks found. I'm thinking the only way Ill be able to figure this out is to put it up on the hoist in gear and load it with the brakes.

 

[Mark_88]

I've heard a great deal of noise from a cracked EGR pipe so I would suggest maybe some liquid metal on that to see if it quiets it down. It doesn't actually take much of a hole to make it loud...so a small crack can let out plenty of noise...

 

[traacer]

I had the same problem, ended up being my header gasket. Replaced that and quiet as it should be.