Boat not in the water yet - exhaust manifold overheat - DTC 441 & 442

Donald

Donald

Joined
Mar 21, 2004
Messages
29,615
Location
Near the beach in Delaware
It's good I like working on my boat. In my continuing saga I put my Chaparral in the water and and idled it at the dock. After 5 or 8 minutes I got red triangle alarm. Then rapid alarm. Got the Diacom and read the code. DTC 441 and 442. Exhaust manifold overheat. Volvo Penta V8 300-C-A closed cooling. I ran it on muffs the month before without issue but maybe not long enough. The boat had not been really run in the water (more than idle at the dock) since Sept 2020, last year it was a complete outdrive rebuild waiting for parts.

Took out sea water impeller and examined for cracks, damage and flexible rubber, looked fine so I reinstalled it.

Does anything think running engine of muffs with the water pressure and cold-ish temp water from a garden hose could mask problems in the sea water flow (partially clogged oil cooler) that would show up when the boat is in the water?
 
Is water circulating through the manifold? Could the sensor faulty..
 
Typically would mean your exhaust manifolds need replacement as they are clogged with rust etc.
From what I remember you telling me you have freshwater Cooling, unless I’m wrong but I’m almost certain the sea water, after it runs through the heat exchanger, dumps into the exhaust manifolds to exit the boat.
At least that is what a Mercruiser I had did many decades back.
Worse yet is if I remember correctly you have a 2011 boat which would likely mean that you have catalytic converter’s and clogged converters could be prime suspect too?
 
Last edited:
AZjeff said:
No help but props for hanging in there, that boat has been giving you a hard time. Is the second best day of your life in the future?
Click to expand...
Well wife is frustrated as we spent $50K on a boat we have not been able to use yet. But I like working on my boat so it's just another day working on something with an engine.
 
wpod said:
Is water circulating through the manifold? Could the sensor faulty..
Click to expand...
It's got a DTC for each side. So unlikely both sensors. I did not but will get my IR thermometer and read some temps.

It's got two temp sensors on each side one for exhaust manifold and one for the riser. Unsure if a DTC 441 saying exhaust manifold overheat is specific to exhaust manifold and there is another DTC for riser overheat or is a DTC 441 a generic for exhaust system overheat on that side.

The catalitic converter is inside and between the exhaust manifold and riser.

The service & workshop manuals are printed only available from the dealer. No PDF on the web.
 
The sea water circuit is a series (strainer, pump, heat exchangers, manifolds)-- any restriction slows down everything. Since you already know of one part that is "partly clogged" it is not helping. In salt water, the manifolds and elbows always clog up with rust, cleaning them out is routine maintenance until they rust through. Then it is time to Break Out Another Thousand.

Boats are the second thing on the Three F's Rule of things to always rent not buy.
 
alarmguy said:
Typically would mean your exhaust manifolds need replacement as they are clogged with rust etc.
From what I remember you telling me you have freshwater Cooling, unless I’m wrong but I’m almost certain the sea water, after it runs through the heat exchanger, dumps into the exhaust manifolds to exit the boat.
At least that is what a Mercruiser I had did many decades back.
Worse yet is if I remember correctly you have a 2011 boat which would likely mean that you have catalytic converter’s and clogged converters could be prime suspect too?
Click to expand...
It's full freshwater cooling. The block and exhaust manifold are cooled by normal engine coolant. The riser is sea water cooled.
 
mk378 said:
The sea water circuit is a series (strainer, pump, heat exchangers, manifolds)-- any restriction slows down everything. Since you already know of one part that is "partly clogged" it is not helping. In salt water, the manifolds and elbows always clog up with rust, cleaning them out is routine maintenance until they rust through. Then it is time to Break Out Another Thousand.

Boats are the second thing on the Three F's Rule of things to always rent not buy.
Click to expand...
I don't know anything that is partially clogged. Although I will examine the oil cooler. It's inline between the outdrive and raw water pump.
 
Years back, I had a 6 cyl Chevy I/O that started to over heat in the spring. The funny thing was, it could idle at the dock for an hour and the temp would be in the normal range. In the fall I winterized it like I did every year. But as soon as I pulled away from the dock, and gone about 300 feet, the needle was pegged. As best as I could tell water was coming out thru the prop, like it should. So i replaced the thermostat, and gave it another try. Same thing, hot in 300 ft. No water in the oil, and nothing unusual anywhere. So the last thing I did was to pull the water pump off the engine. Low and behold I saw the problem. I guess what happened was, over the winter the stuff I used to winterize the block must not have been the right mixture for the temp. I guess it almost froze solid and pushed the propeller off the water pump shaft, so just the shaft was spinning. And not enough water was being circulated thru the block for proper cooling. The pump in the out-drive would fill the block, but didn't have enough pressure/ volume to push it thru the block before it got too hot. I changed the pump and that solved the problem.,,
 
I may have found the problem. Or a least a problem. The coolant level in the overflow was low, maybe 1/2" so I figured it was low but OK and I would add the Volvo Penta VCS coolant when I finally found some. (Not easy to find). I added a gallon and it took the whole gallon. Level came to 1". Needs even more. The full mark is at about 3" on the overflow. I bought last gallon from one mail order company. Ordered two more gallons from another.
 
What fooled me a little with overflow is with a car the coolant is not up high like it is with the water cooled exhaust manifold and riser that go above the heads. So the coolant level really needs to be correct or close to being correct in a marine engine with closed cooling.
 
Last edited:
Donald said:
It's good I like working on my boat. In my continuing saga I put my Chaparral in the water and and idled it at the dock. After 5 or 8 minutes I got red triangle alarm. Then rapid alarm. Got the Diacom and read the code. DTC 441 and 442. Exhaust manifold overheat. Volvo Penta V8 300-C-A closed cooling. I ran it on muffs the month before without issue but maybe not long enough. The boat had not been really run in the water (more than idle at the dock) since Sept 2020, last year it was a complete outdrive rebuild waiting for parts.

Took out sea water impeller and examined for cracks, damage and flexible rubber, looked fine so I reinstalled it.

Does anything think running engine of muffs with the water pressure and cold-ish temp water from a garden hose could mask problems in the sea water flow (partially clogged oil cooler) that would show up when the boat is in the water?
Click to expand...
I never run my ob on muffs. Gotta lake nearby.
 
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