Mercruiser 5.0 freeze damage cracked manifolds ?

[Chudwick]

Hey fellas. I waited too long to winterize last season and cracked the block at the water jacket. I’m pleased to say that the repair was a success and it is no longer leaking. Well after some other non freezing repairs I have it up and running. It sounds fantastic on muffs in the driveway but there is quite a bit of steam when I’m running at 1500 rpms and up. It is pretty cold up here in jersey still but it has me a little nervous. The engine is a 5.0, the risers are running at about 65 degrees and the manifolds are coming in at 165 and 180. Water flow coming out the transom looks normal and the water is about the temperature of a nice warm shower. My concern is that the manifold/risers may have been damaged when the block cracked. They are the dry joint style manifolds so I understand them to be quite more sturdy than the old style. You guys think they’re cracked ?

 

[Bondo]

but there is quite a bit of steam when I’m running at 1500 rpms and up. It is pretty cold up here in jersey

Ayuh,...... The risers are dumpin' the water into a stream of gas that's 600* to 900* as it comes outa the manifold,.....

There's Gonna be steam,......

Local weather conditions also play a Huge roll in what you see,......

 

[Chudwick]

Thanks for the vote of confidence bondo. I’m going to run it and if it blows up I’ll give an update. I’m due for a repower anyway !

 

[Scott06]

Steam is normal, is the engine oil clean and not milky, just need to watch for water getting in the oil. My neighbor had the same thing a couple years ago, thought he as in the clear but afte 3-4 uses was getting water in the oil. Think it took a couple of uses to get the crack in the oil valley to open up.

 

[crazy charlie]

I would expect to see some steam .I would also not be surprised at all if you found more damage as you already suspect.You mentioned something about running 1500 rpm and above...If you are talking about on muffs ,it really is not recommended to run above 1100 rpm on muffs if you dont want to ruin your impeller which you may have done already.Charlie

 

[scoflaw]

Pull some spark plugs. Dry joint has nothing to do with withstanding freeze damage

 

[Chudwick]

I was going to take it out this weekend to test it out. Since I’m replacing the manifold I may as well dump the oil too to see if it’s milky now. It wasn’t before but the manifold wasn’t cracked then either.

 

[Chudwick]

I just realized this is a different thread. Yeah, port side manifold developed a crack I spotted yesterday. I was debating running for a couple hours with the cracked manifold to see what else would turn up after some hard riding but the guys talked me out of it.