Should I replace my exhaust manifolds?

[CurrentObsession]

I have a 12 year old 350 cid thunderbolt engine on my 23' bowrider. I have run it in freshwater since purchasing it last year, but I believe it has been in brackish water most of its life. Does it make sense to proactively change them out prior to failure, or should I just stick to the moto of "If it ain't broke, don't fix it"?

 

[Bondo]

Re: Should I replace my exhaust manifolds?

I have a 12 year old 350 cid thunderbolt engine on my 23' bowrider. I have run it in freshwater since purchasing it last year, but I believe it has been in brackish water most of its life. Does it make sense to proactively change them out prior to failure, or should I just stick to the moto of "If it ain't broke, don't fix it"?

Nope, but I'd pull the risers off 'em to Inspect 'em...

Then decide if new 1s are needed...

 

[CurrentObsession]

Re: Should I replace my exhaust manifolds?

What dpo I look for? Are the "risers" the actual cast manifiolds?

 

[Bondo]

Re: Should I replace my exhaust manifolds?

What dpo I look for? Are the "risers" the actual cast manifiolds?

Ayuh,... The Manifolds bolt to the motor,...
The risers bolt to the manifolds...

The gasket surfaces between the 2, tend to rust, 'n erode...
Those gasket surfaces determine whether there's any life left in 'em...

 

[Don S]

Re: Should I replace my exhaust manifolds?

If you are not sure about the condition of the gasket surfaces between your manifolds and elbows, post some pictures of them.

 

[arks]

Re: Should I replace my exhaust manifolds?

....and if you find them OK, be sure to use new matching gaskets and 'rod out' the cooling ports before re-installing them. Rodding will knock off any loose scale.
One other thing- Soak those manifold bolts with penetrating oil before putting a wrench to them. Nothing ruins a day more than having to replace a broken stud.