Exhaust Manifolds

[WSUDERMAN]

Instead of bringing the old topics to the top, Thanks to all who replied to my other posts…<br />I was doing the annual maintenance to get my boat ready for the upcoming season (Yes here in sunny Phoenix we get to start early). After completing all the work, I did a test run and noticed some water beginning to accumulate in the bilge. Boats in the garage so I look around and found a 4” long crack in the exhaust manifold. It starts at the joint with the elbow and runs almost straight down the manifold. Upon further inspection it looks as if this crack has been there for a while, lots of rust, mineral deposits (we have very hard water) and paint flaked off around the crack.<br />I hope to have it off the motor tonight for a better inspection.<br /><br />Here is the question, Can I have this welded up? (Assuming the inside water jacket is not compromised)<br />What are the risks?<br />OR Should I just get a replacement?<br /><br />It’s a OMC/GM 305(5.0l) motor<br /><br />Wes

 

[Walter]

Re: Exhaust Manifolds

I believe the manifold can be welded...just needs to be pre-heated. I had this done on my MerCruiser. However, a few years later the same manifold failed and trashed my engine. The interior water jacket allowed water to leak into the number 2 cylinder... Therefore, based upon my experience...I suggest replacing it.<br /><br />For what it's worth...<br /><br />Walt

 

[DJ]

Re: Exhaust Manifolds

I would REPLACE it. You don't want to risk the engine. You can usually find aftermarket replacements. Try this website.<br /> www.part-man.com Ask about Osco manifolds.

 

[WSUDERMAN]

Re: Exhaust Manifolds

Thanks for the input Walter and djohns19! And thanks for the link. Looks like i will be in the market for a new manifold.<br /><br />I was wondering if I will need to replace both manifolds because of flow-rate differences between the Aftermarket manifold and the stock one.<br /><br />I don't have enough cash to replace both sides so if this is a must, i might have the crack welded and save up to replace them next season...