2012 VP 300 C-A Exhaust manifolds getting too hot - DTC 441 & 442

Lou C

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Wow that’s really interesting! I’m going to get one of those!
 

Donald0039

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When filling the cooling system, it can be tough to get all the air out. Generally speaking you want the RPMs up to about 1500. Some engines can be really hard. Back in the late 90s/early 2000s there were some "blue" 5.7L engines that the factory would send us special thermostats with some holes drilled in them to try and help get the air out, still had problems and the factory wanted me to run the engine at 4000 RPMs while filling! No way I'm standing next to a engine running that fast with no load! That's how people get hurt.

Bought one of these and never had a air problem again.


Not this exact brand, but looks pretty close.
I have one of those but what would I need to do? Cooling System is full, maybe with some air pockets. Drain the system and fill using the vacuum filler?
 

muc

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I drained mostly empty first. A couple of reasons. If the tool starts sucking coolant it will make a antifreeze mist that I don’t want to breath. Also it really slows down how fast you can draw a vacuum and my labor charge was more then the cost of coolant. Plus new coolant is better than old coolant.

The advice I give here is based on my many years as a tech. My employer charged above market rate for my time because they felt I was above average due to my skills. This forced me to think about what’s best for the customer. An example of this is something as simple as a dead battery. Customers would want to know why I didn’t “just recharge it”. I would have to explain that by the time I got done with charging and testing their old battery. I could have installed a new battery for the same or less cost. “Do you want a new battery or a recharged used battery for the same price?”

So take my advice with a grain of salt, My customers paid for top of the line service and I tried my best to deliver.

To run one of these Venturi vacuum pumps requires a pretty large air compressor I usually used the shop compressor but one time I had to go to a remote location and brought my little 5hp craftsman compressor. It barely got the job done, had to draw some vacuum, let the compressor catch up and draw some more a few times.
 

Donald0039

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I drained mostly empty first. A couple of reasons. If the tool starts sucking coolant it will make a antifreeze mist that I don’t want to breath. Also it really slows down how fast you can draw a vacuum and my labor charge was more then the cost of coolant. Plus new coolant is better than old coolant.

The advice I give here is based on my many years as a tech. My employer charged above market rate for my time because they felt I was above average due to my skills. This forced me to think about what’s best for the customer. An example of this is something as simple as a dead battery. Customers would want to know why I didn’t “just recharge it”. I would have to explain that by the time I got done with charging and testing their old battery. I could have installed a new battery for the same or less cost. “Do you want a new battery or a recharged used battery for the same price?”

So take my advice with a grain of salt, My customers paid for top of the line service and I tried my best to deliver.

To run one of these Venturi vacuum pumps requires a pretty large air compressor I usually used the shop compressor but one time I had to go to a remote location and brought my little 5hp craftsman compressor. It barely got the job done, had to draw some vacuum, let the compressor catch up and draw some more a few times.
I understand what you are saying. My issue right now is finding the coolant. My local dealer does not stock it so I ordered a case from them. I have ordered some online but they are out of stock now.

Maybe I could drive out the air by rev'ing the engine several times?
 

muc

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I understand what you are saying. My issue right now is finding the coolant. My local dealer does not stock it so I ordered a case from them. I have ordered some online but they are out of stock now.

Maybe I could drive out the air by rev'ing the engine several times?
Don’t rev the engine. Slowly increase RPMs. Check the small hose I mentioned earlier. That’s there to bleed the air out.
 

muc

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I should have said the only reason the small hose is there is to bleed the air out.
 

Donald0039

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I should have said the only reason the small hose is there is to bleed the air out.
I will check the small hose. Then 1500 RPM for 2 minutes will drive any trapped air out if that way is going to work? Faster? Longer time?
 

Lou C

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I will check the small hose. Then 1500 RPM for 2 minutes will drive any trapped air out if that way is going to work? Faster? Longer time?
I will check the small hose. Then 1500 RPM for 2 minutes will drive any trapped air out if that way is going to work? Faster? Longer time?
I should have said the only reason the small hose is there is to bleed the air out.
Ah I knew they must have had a way to do that given the design of the exhaust manifolds
 

muc

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I will check the small hose. Then 1500 RPM for 2 minutes will drive any trapped air out if that way is going to work? Faster? Longer time?
That's where to start, some need longer some need faster. Sounds like idle speeds are not enough. And do this in the water or at least make sure the engine is level.
 

Donald0039

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Got to the boat today and one of the caps in the cooling pressure test kit fit so I did a cooling system test.

Lost 2 lbs in 30 min.

Expansion tank was down only 1 PT from last test run where is overheated.

So one of my thoughts for a potential problem was I had lost a lot of coolant during the last test run through the heat
That's where to start, some need longer some need faster. Sounds like idle speeds are not enough. And do this in the water or at least make sure the engine is level.
Got to the boat today and one of the caps in the cooling pressure test kit fit so I did a cooling system pressure test.

Lost 2 lbs in 30 min.

Expansion tank was down only 1 PT from last test run where it overheated.

So one of my thoughts for a potential problem was I had quickly lost a lot of coolant during the last test run through the heat exchanger and it overheated due to being low on coolant. I now do not think that is a possibility.

Now I am thinking air in the system and the pint of coolant that the expansion tank was low was due to air in the exhaust manifolds. Probably some more air in the exhaust manifold but not sure.

I am thinking the loss of 2 lbs in 30 min is OK and not a leak I need to be concerned with.
 

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muc

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I am thinking the loss of 2 lbs in 30 min is OK and not a leak I need to be concerned with.
If this was a pressure test on a full and cold system. No it's not OK, you have a leak.
 

Donald0039

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If this was a pressure test on a full and cold system. No it's not OK, you have a leak.
Ok, while it's a leak I need to deal with it's not the cause of the overheating as long as I keep my eye on the coolant level. Is air in the cooling system the problem?
 

muc

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Ok, while it's a leak I need to deal with it's not the cause of the overheating as long as I keep my eye on the coolant level. Is air in the cooling system the problem?
The problem with air in the system is that it degrades the coolant you're using. What you have now lasts about 5 -6 years before it stops protecting against corrosion. Keep adding air to it and that life starts dropping. All depends on how long you want to keep the boat. I used to joke with customers that bought a new boat every two years that they really didn't need to any maintenance at all!

What does the heat exchanger anode look like?
 

Donald0039

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The problem with air in the system is that it degrades the coolant you're using. What you have now lasts about 5 -6 years before it stops protecting against corrosion. Keep adding air to it and that life starts dropping. All depends on how long you want to keep the boat. I used to joke with customers that bought a new boat every two years that they really didn't need to any maintenance at all!

What does the heat exchanger anode look like?
I agree the leak does need to be dealt with but what is causing the overheat? Once I resolve the overheat I am plan to pull the heat exchanger and get is tested and possibly repaired. Or replaced.
 

Donald0039

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The problem with air in the system is that it degrades the coolant you're using. What you have now lasts about 5 -6 years before it stops protecting against corrosion. Keep adding air to it and that life starts dropping. All depends on how long you want to keep the boat. I used to joke with customers that bought a new boat every two years that they really didn't need to any maintenance at all!

What does the heat exchanger anode look like?
I am thinking my next test is to try and get rid of any trapped air by running the engine at 1500 for 2 or 3 minutes.

If the goal is to get rid of the trapped air is it best to run with the cap for the expansion tank off.

With a leak potential in the heat exchanger I guess I don't want to pull a vacuum on the cooling system to fill it that way.
 

Lou C

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Even if the engine doesn’t overheat due to the design of the exhaust manifolds if the air pocket just happens to be right near the location of the temp sensor then you can get those codes I’m guessing. So for it to not have any codes you probably can’t have any leaks at all in this system. I’d take an IR temp gun and take readings all over the manifolds till you find the area that is close to the temp your fault code is telling you…that might be where there is either an air pocket or a passage partly blocked by corrosion.
Sigh
Lost simplicity…
Volvos previous exhaust was a simple manifold & elbow fed by one hose. When it’s time for replacement (here every 5-7 years) you bolt up an aftermarket Barr Marine system for $725 parts cost & go boating. These new systems are pushing people out of boating. I know a few people that when faced with the cost of replacement (Mercruiser $4500 for a V6) just sold the boat & got out of boating….
 
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Donald0039

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Even if the engine doesn’t overheat due to the design of the exhaust manifolds if the air pocket just happens to be right near the location of the temp sensor then you can get those codes I’m guessing. So for it to not have any codes you probably can’t have any leaks at all in this system. I’d take an IR temp gun and take readings all over the manifolds till you find the area that is close to the temp your fault code is telling you…that might be where there is either an air pocket or a passage partly blocked by corrosion.
Sigh
Lost simplicity…
Volvos previous exhaust was a simple manifold & elbow fed by one hose. When it’s time for replacement (here every 5-7 years) you bolt up an aftermarket Barr Marine system for $725 parts cost & go boating. These new systems are pushing people out of boating. I know a few people that when faced with the cost of replacement (Mercruiser $4500 for a V6) just sold the boat & got out of boating….
The issue is on the closed cooling side and I see no indication of any corrosion as the coolant looks in new condition. And the temp sensor in exhaust manifold is along the top surface where an air pocket is likely to be.

Remember it's happening at the same time on both exhaust manifolds so some type of blockage due to corrosion in the exhaust manifolds on both sides with closed cooling is unlikely.

Air pockets could be on both sides as the exhaust manifolds are identical and at same height.
 

muc

"Retired" Association of Marine Technicians...
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Even if the engine doesn’t overheat due to the design of the exhaust manifolds if the air pocket just happens to be right near the location of the temp sensor then you can get those codes I’m guessing. So for it to not have any codes you probably can’t have any leaks at all in this system. I’d take an IR temp gun and take readings all over the manifolds till you find the area that is close to the temp your fault code is telling you…that might be where there is either an air pocket or a passage partly blocked by corrosion.
Sigh
Lost simplicity…
Volvos previous exhaust was a simple manifold & elbow fed by one hose. When it’s time for replacement (here every 5-7 years) you bolt up an aftermarket Barr Marine system for $725 parts cost & go boating. These new systems are pushing people out of boating. I know a few people that when faced with the cost of replacement (Mercruiser $4500 for a V6) just sold the boat & got out of boating….
You have this backwards. Liquid transfers heat better than air/vapor.
 

Lou C

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Messages
11,798
You have this backwards. Liquid transfers heat better than air/vapor.
I Thought that's what I said...if there are air pockets not filled with coolant, then you have hot spots...
 

Lou C

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Messages
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The issue is on the closed cooling side and I see no indication of any corrosion as the coolant looks in new condition. And the temp sensor in exhaust manifold is along the top surface where an air pocket is likely to be.

Remember it's happening at the same time on both exhaust manifolds so some type of blockage due to corrosion in the exhaust manifolds on both sides with closed cooling is unlikely.

Air pockets could be on both sides as the exhaust manifolds are identical and at same height.
An exhaust elbow that was used in salt water can look great on the outside but could be all rotted out under the hoses where you can't see and the ONLY way to tell if your cooling passages are open is to take it apart, if you are suspecting a blockage due to hot running temps. In your case the manifolds are on the AF system but the elbows, are still raw water cooled, if they are getting clogged, maybe that is contributing to your elevated temps.
look at these Merc dry joint elbows, they look fine except for what's hidden under the rubber exhaust hoses:merc dry joint elbows after  4.5 years in salt water.jpg
and here is an OMC one piece V6 manifold I used to have on mine after 5.5 seasons in salt water, compared to new....not too bad but you can see one of the 4 exit ports is blocked with corrosion. Probably about 200 hrs of use. By 7 seasons it would have caused a major exhaust overheating problem.
OMC batwings after 5.5 seasons vs new.jpg
So in your case I'm just guessing of course but trapped air and/or corrosion could be the cause, even if they look good outside.
With the old style Volvo and Merc wet joint exhaust as soon at they started to show rust stains on the outside you had to take em apart because that meant they could be leaking on the inside which on those systems would put water into the center exhaust passage.
In fresh water regions this is mostly a non-issue from what I hear but here in the salt pond it is regular maintenance, or else you risk engine damage from rotted out exhaust parts and safety risk due to burning up the rubber exhaust hoses.
 
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