Bought new 4.3 block, do I need new exhaust too?

[brsox88]

So my 4.3 block cracked due to not being winterized by previous owner (milky oil started coming from the header/valve cover vents) so I bought a new block from RapidoMarine and have a local marine mechanic coming to help me do the change over, timing, etc.

My question is, should I buy all new exhaust manifolds and risers even if the engine ran very smooth and quiet before? Like wouldn't I have heard something if water was trying to re-enter the engine? Or can I just give it a very good cleaning and look over?

 

[Bondo]

Ayuh,.... The manifolds can be blocked off, 'n pressure tested with air,...

The risers can be inspected, 'n or replaced if issues are found,....

 

[Scott Danforth]

acetone test works too

 

[brsox88]

Thank for the answers so far, do you guys know of an easy guide to test with the ways you mentioned? I assume I just block off one end and fill with acetone to see for leaks, sounds expensive as its like $8 a quart where I am.

 

[tlewis1]

Check in the Adults Only section there is a method for testing the manifolds

 

[tpenfield]

I am thinking if the engine block cracked due freezing, the manifolds probably did too. :noidea: