Risers and manifolds - life expectancy in salt water question

luvinlife

I have a 2006 FV 270 with a Volvo 5.7 MPI. I replaced the risers and manifolds as a preventative measure in the spring of 2017 and have put about 200 hours on the engine in 4 seasons, slipped in salt water. Our season is 5 months here in RI. I fresh water flush intermittently, but not religiously. Thoughts on life expectancy? Time to replace again?  They look brand new externally. 

aero3113

@luvinlife , do you have dry joint or wet joint?

luvinlife

Good question aero but I don’t know. 

Handymans342

The exterior can look good. Its the inside you need to worry about

aero3113

Post a pic of your engine if you have, they’re pretty easy to identify.

aero3113

Also depends if your fresh water cooled (closed cooling).

reneechris14

Volvo is a wet joint and the risers and manifolds are raw water cooled, doing my 8.1 right now and I wish I could change to fresh water cooled as I'm in for $2500 for new ones. But to answer @luvinlife 5 years is the normal for this area. Mine were said to be 3 years old and did not look to good.

reneechris14

I probably should of went with mercuiser manifolds and risers as I believe they are a better set up.

andyd

Six years since replacing the risers. No idea of what the inside looks like but no apparent issues. My 2006 5.0 V-P motor has the Neutra-Salt system. However instead of using that I like to flush the risers with a fresh water/SaltAway mix by attaching a garden hose to the blue flushing port which is on the starboard front side of the motor. I run the engine at idle with the water running for 5 minutes. Hopefully I'm extending the riser's useful life, but honestly I don't know. Andy

J3ff

my risers on a fresh water cooled system looked pretty bad after 4 years!

rasbury

When I replaced my 06 parts, my elbows were shot- I replaced those and the risers.  Manifolds never see the water so if yours needed to be replaced then something else to that...even the risers didn't look bad and I'm sure they were never replaced.

oscar1

I replaced my manifold and rise after 8 year of seawater use in miami

aero3113

@oscar1 , do you have dry joint manifolds? The areas that the raw water passes through are much thicker with dry joint, they last longer then wet joint. 

aero3113

I’ve read with dry joint, you can wait till you notice your engine temp is a little higher than normal then replace.

aero3113

Here are a couple of screen shots showing the difference between the two types.

oscar1

the new one dry one style.

oscar1

oscar1

after 8 years of use in salt water in miami

andyd

"Rust never sleeps" - said some wise man.