Cracked Manifold - Mercruiser 5.7L 260 HP Safe? Replace Both?

[rocklydockly]

I have a '95 Rinker with a 5.7L Mercruiser I/O 260HP. The Starboard Exhaust Manifold is cracked along the outside face between the two center exhaust ports. I can see evidence of water coming through (rust) and once the boat is warm while under way, I do take on water from the crack. I've not seen it, but I've seen the water and now today I've seen the crack.

Perhaps a stupid question, but can I take it out as is for this weekend? What are the risks, both safety and what else might I break?

Second question do I replace both sides as its just a matter of time, or do I wait for the other side to have a problem too?

The replacement job looks relatively easy to access, I'm guessing the bolts are a bear to get off do to the exhaust heat. I'm relatively handy with automobiles. Is this something a backyard mechanic should attempt?

Anything else I should be looking at. I think the crack developed at the end of last season and the boats probably been out 6 times with the crack. I'm sure like anything that is broken, that it is getting progressively worse.

Thanks in advance for any advice.

PS Know anybody with reasonable price for quick shipping of parts?

 

[wca_tim]

Re: Cracked Manifold - Mercruiser 5.7L 260 HP Safe? Replace Both?

You're playing russian roulette every time you go out... all it takes is one good leak on the inside and youre engine could be toast...

do yourself a favor, bite the bullet and replace both sides, manifolds and risers...

 

[rocklydockly]

Re: Cracked Manifold - Mercruiser 5.7L 260 HP Safe? Replace Both?

Thanks, I realize that this is good advice. Since posting, I've been searching the threads (I know not the right order of things.) The advice out there is consistent and clear regarding fixing it right and doing both sides.

Where do you suggest I order the parts assuming that I attempt the job myself.

I have a lot of room in the engine compartment and it looks pretty straightforward. Each manifold looks like it will be about $150 plus shipping, and I haven't quite figured out the risers yet. I think I saw a total Sierra package w/ 2 manifolds, 2 risers, all gaskets for about $425 + shipping.

Any thoughts on the difficulty? Is this my excuse for buying some pneumatic tools and a compressor or is that overkill?

 

[rather_be_boatin]

Re: Cracked Manifold - Mercruiser 5.7L 260 HP Safe? Replace Both?

I just did this job, sounds like your looking/priced out aftermarket. Everything I read/heard about aftermarket was they will only last about 2 years. I went with Mercruiser risers/manifolds and it was about $800 total for the 4 parts and gaskets. Easy enough job to do, forget air tools and just get a seloc manual and a 0-200" 3/8's tourque wrench.