2006 5.0 Volvo Overheating

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At The End Of Summer I Was On Boat Trip And On The Way Back In The Deleware Bay I Was At Medium Throttle At About 3500 Rpm When The Starboard Engine Burnt Thru The Rubber Exhaust Hose On The Left Top Side Of The Engine And Started Blowing Water In The Engine Hold So I Had To Call Seatow.
I Took The Boat To A Local Monterey Dealer (don't Know If They Knew What They Were Doing, The Engine Got So Hot It Melted Both Of The Temp Sensors On The Risers And No Alarm Sounded. The Temp Gauge On The Dash Stayed At Normal Temp For That Engine.
The Only Thing The Dealer Did Was Replace The Senders And The One Exhaust Bellows Hose And Said It Was Fine, No Codes In The Ecm ????
I Am Very Worried About This Happening In The Future.
Any Help Would Be Appreciated.
Julius

 

[bruceb58]

Re: 2006 5.0 Volvo Overheating

It is possible you picked up a plastic bag on your drive that temporarily blocked your water pick-up. When was the last time you changed the water pump impeller? I would definitely do that. It is an easy job.

 

[havasuboatman]

Re: 2006 5.0 Volvo Overheating

When an engine gets that hot, everything is most definately not "ok".
You need to find out which sender activates your warning buzzer and test it. You also need to get behind the motor and give the hose that wasn't replaced a squeeze. If it feels soft, it has to be replaced too. I find it impossible to believe there where no codes in that engines stored memory.
Take your boat to another boat shop. If you don't want to do that, I strongly reccomend that you back the boat into the water and fire it up. Just let it run a little while, watch the temp gauge and keep your hand on the exhaust riser that burned the bellows.
I have seen boats that caught fire from burning thru those exhaust hoses.
You are right to be worried.

 

[rodbolt]

Re: 2006 5.0 Volvo Overheating

you most likly have a clogged manifold or manifold to riser joint.
would not be the the first boat I ever saw with the riser temp alarms not wired correctly when it got rigged either.
with the temp guage at normal but both risers temp switchs melted I would look at seawater pump and manifolds.
manifolds on that motor in saltwater typically live about 4 years max.
with the key on engine off ground a riser temp switch lead and see if the alarm actually sounds.