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

Donald0039

Petty Officer 3rd Class
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Jun 11, 2022
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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

"Retired" Association of Marine Technicians...
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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

Petty Officer 3rd Class
Joined
Jun 11, 2022
Messages
78
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

"Retired" Association of Marine Technicians...
Joined
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Messages
1,845
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

"Retired" Association of Marine Technicians...
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I should have said the only reason the small hose is there is to bleed the air out.
 

Donald0039

Petty Officer 3rd Class
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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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Nov 10, 2002
Messages
9,998
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

"Retired" Association of Marine Technicians...
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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

Petty Officer 3rd Class
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Messages
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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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Donald0039

Petty Officer 3rd Class
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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

"Retired" Association of Marine Technicians...
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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

Petty Officer 3rd Class
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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.
 
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