5.0 exhaust tick, already replaced both manifolds

[masospaghetti]

I still have an exhaust tick, more noticeable when cold, also more noticeable with the windows open. Both manifolds were replaced with the cast iron style with new gaskets. I've hooked up the exhaust pipe to a vacuum (sucking, not blowing) and was not able to find anything under the vehicle, even with a stethoscope.

My engine has the internal EGR system. There's no visual evidence of leaks and the valve itself looks fine. There's no EGR pipe to crack and break.

What would you do next? Do all 5.0's just have this tick, no matter what? It's a 96 model, 151,000 miles...thanks guys/gals..

 

[vroomzoomboom]

might sound kinda dumb, but have you also checked your plugs to make sure they are fully seated in the heads? they might be loose enough to let compression by. also, plug wires sometimes can have a tick to them if they are cracked and arching. long shot, but who knows.

 

[masospaghetti]

Thanks for the reply. The plugs and wires are new but worth checking again.

It gets louder under load, which tells me its exhaust related.

 

[Turdle]

Suck a little seafoam up a vacuum line and shut off the engine. Let it soak for a while while you remove the serpentine belt. Fire up the truck and watch where the smoke comes out.

removing the serpentine belt will prevent the fan from blowing the smoke and hiding the source.

Which exhaust manifold gasket did you use? Did you get all of the old gasket off? leaving just a little will cause a leak.

edit, another question. did you replace the manifold with new or used? Tubular or cast? did you replace the with manifolds from a 96?

 

[masospaghetti]

I used the manifold gasket that came with the manifold. Dorman cast-style manifold to replace the tubular-style ones. They were bought new.

That's a good tip for the seafoam, I will try that.

I spent quite a bit of time cleaning the mating surfaces, I think I got all of the old gasket off.

 

[Turdle]

Actually, scratch my last post. Just remove the fan blade. You may need to run the engine for a bit, without the belt there will be no drive to the water pump. I think it will be ok for quite a few minutes without a fan, as long as coolant is circulating.