Running hot

kloudie1 · Oct 29, 2021

Yes and a known good pressure cap . Then if he still has overheat problems, troubleshooting can start from there. Is it a Yanmar?

dlochner · Oct 29, 2021

Yes the advice is sound.

The 50/50 mix of antifreeze has a greater heat capacity than either water alone or AF alone. This means that it takes more heat energy to raise the temperature of the coolant 1° than it takes to raise water 1°, thus the engine coolant will run cooler and the engine will run cooler and at its designed temperature.

Additionally, AF contains rust inhibitors and other stuff to keep the engine's innards happy and functioning.

jssailem · Oct 29, 2021

All U Get said:
Am I giving him the best advice?

It is “all U get”.
Running hot.

Is a relative phrase.
Taking out the thermostat sounds like an action to treat a symptom. Start simple and work towards the involved. @kloudie1’s advice to use coolant and confirm the pressure cap is operational is spot on.

Let the results of this action lead you further. Getting the proper thermostat installed will better support the engine.

DeniseO30 · Oct 29, 2021

Would you share what this engine model is that you have in common with the other person?
Yanmars of course are notorious for exhaust elbow problems

dlochner · Oct 29, 2021

DeniseO30 said:
Would you share what this engine model is that you have in common with the other person?
Yanmars of course are notorious for exhaust elbow problems

The problems described, excessive over heating and scale in the motor could be symptoms of problems with the exhaust elbow, but in this case it almost certainly the result of using plain water as coolant. When it was overheating, the owner probably took the thermostat out to prevent overheating, thinking that free flow of water through the block would cure the problem, it didn't.

Restrictions in cooling water flow through the heat exchanger caused by scaling or restrictions in the exhaust elbow may be contributing, however, until the proper coolant is in the system the problem won't go away. Additionally, clogged elbows are caused by running the diesel too cold with unburned and partially burned fuel condensing on the inside of the elbow. A motor running hot would tend not to have crud built up in the elbow. If either of these were causing the problem, there would be a reduction of water flow out the exhaust. That was not reported as a symptom.

The fastest cheapest solution is to buy a gallon of appropriate antifreeze and a proper thermostat. Drain the water, add the coolant and see what happens. If adding AF does not resolve the issue, then other parts of the cooling system need inspection.

DeniseO30 · Oct 29, 2021

dlochner said:
The problems described, excessive over heating and scale in the motor could be symptoms of problems with the exhaust elbow, but in this case it almost certainly the result of using plain water as coolant. When it was overheating, the owner probably took the thermostat out to prevent overheating, thinking that free flow of water through the block would cure the problem, it didn't.

Restrictions in cooling water flow through the heat exchanger caused by scaling or restrictions in the exhaust elbow may be contributing, however, until the proper coolant is in the system the problem won't go away. Additionally, clogged elbows are caused by running the diesel too cold with unburned and partially burned fuel condensing on the inside of the elbow. A motor running hot would tend not to have crud built up in the elbow. If either of these were causing the problem, there would be a reduction of water flow out the exhaust. That was not reported as a symptom.

The fastest cheapest solution is to buy a gallon of appropriate antifreeze and a proper thermostat. Drain the water, add the coolant and see what happens. If adding AF does not resolve the issue, then other parts of the cooling system need inspection.

"Correction"
no need for mansplaining lol

I was just suggesting you could share what engine it is so others with that engine, could gain some additional knowledge.
Cheatalcium & soot build up for a constant problem with raw water cooled exchanger engines, it's just the nature of the cooling system; taking superheated gases and super cool them almost instantly; creates lots problems.

I was reading another thread last night the person just went out and bought a new heat exchanger instead of cleaning it! .. okay

dlochner · Oct 29, 2021

DeniseO30 said:
no need for mansplaining I was just suggesting you could share what engine it is so others with that engine, could gain some additional knowledge.
Calcium & soot build up for a constant problem with raw water cooled engines it's just the nature of the cooling system; taking superheated gases and super cool them almost instantly; creates lots problems.

He doesn't have a raw water cooled motor, or else the question of AF would not be raised. Yanmars are typically not raw water cooled.

Dismissing an explanation of something which one clearly does not understand as "mansplaining" limits one's ability to learn from others with perhaps more experience.

Scott T-Bird · Oct 29, 2021

DeniseO30 said:
no need for mansplaining lol

Ha, I got a real kick out of this! Mansplaining is our forte! Dave, I think Denise was being light-hearted about this. It was a simple question ... Do we know the engine model (or if it is a yanmar) in Tom's Pearson? Also, I have anti-freeze in my Yanmar and I also have a raw water pump, with raw water passing thru my mixing elbow. So it is not "raw water cooled" ?

(Are we splitting hairs?)

DeniseO30 · Oct 29, 2021

Just to be clear
I am talking about which the op is also talking about (and still doesn't want to share what engine it is)
raw water cooled exchanger engines,

sail sfbay · Oct 29, 2021

All U Get said:
............I told him this would all go away if he added the 50/50 mix and a thermostat. Am I giving him the best advice?

Just to add to what kloudie1and dlochner said you can advise owner of the importance of antifreeze mixed with mineral-free water:

Reduces the freezing point of the cooling system
Acts as a lubricant for the water pump
Contains different chemicals to maintain the pH levelm and to keep the various engine materials from corroding

And after adding 50/50 antifreeze / mineral-free water in a 50/50 mixture as jssailem indicated and the engine is still overheating then this troubleshooting article might be referred to Troubleshooting a Marine Fresh Water Cooling System | PerfProTech.com

DeniseO30 · Oct 29, 2021

This winter I'll probably get some help and remove the heat exchanger manifold off my Yanmar 3GM30 (I'm collecting parts)
I was looking at the o-rings and it dawned on me that the heat exchanger tube stack on this Yanmar (and probably others goes in and back and then out again separating the upper and lower tubes and making a S circuit .. also explaining to my inquiring engineers mind why these engines run so cool when they're operating properly, but if left the clog up it's a nightmare!

Heat exchangers in general are designed, to come apart and clean, the exception would be the type you see on solar equipment and some on-demand water heating units.

Mostly what we are dealing with is "tube in shell" or "tube stack in manifold" applications.

dlochner · Oct 29, 2021

DeniseO30 said:
Just to be clear
I am talking about which the op is also talking about (and still doesn't want to share what engine it is)
raw water cooled exchanger engines,

I'm sorry, but could you explain what a "raw water cooled exchanger engine" is? I've not heard this term before. I know what a raw or seawater cooled motor is, and I know what a freshwater cooled motor is, and I know what a dry stack is.

Seriously, the forum sees many people who have incorrect, partially correct or no understanding of boat systems. It is the culture here on this forum to share our knowledge. Many of us are willing to take great effort to provide correct and accurate information, that's why Tim asked his question here and he's a knowledgeable guy. For the question he asked and the manner in which he asked the question, the particular brand of motor is not all that relevant. It would make no sense at all to advise someone to add AF to a raw or seawater cooled motor, you might just as well pour a gallon jug of AF into the water.

Tim's friend, the one he is asking about, clearly doesn't know what AF does and does not understand the chemistry of cooling liquids at even a most basic level. The longer answers given provide him with explanations in different manner so that he can help his friend stop wrecking his expensive motor.

At a personal level, understanding why and how something works is far more valuable to me than simply knowing a fact, it is far more valuable to understand the benefits of and the mechanisms by which AF works than to simply know that I should put AF in my freshwater cooled diesel.

If you should find my sometimes lengthy responses annoying, irrelevant, or "mansplaining" then feel free to skip over them. No need to read them and complain.

DeniseO30 · Oct 29, 2021

Raw water Imo, is usually fresh water, sea water is usually salt water, but both are raw water pumped into something, either the engine itself or the heat exchanger cooling circuit that is designed to cool.

The closed circuit system of an engine in essence has radiator has replaced with a heat exchanger or a keel cooler,

All this can lead to the question

" what is a heat exchanger?"

they can be all kinds of configurations.

a radiator is a water-to-air, an air conditioning unit is refrigerant air or air to refrigerant depending on the cycle it is in, a water collector using solar as the medium called a solar collector is also a heat exchanger.
Then we can go into automotive with transmission oil coolers or engine oil coolers they are also a heat exchangers often oil to air or oil to water.

kloudie1 · Oct 29, 2021

Yanmars (GM, HM, and a few others) have a peculiar thermostat arrangement in that it opens and closes two different ports instead of one as in a "normal" engine.. If the thermostat is removed on those engines, they may run hotter than with the thermostat in place. Attached shows that with the thermostat out, the bypass is wide open, reducing flow through the heatex. The main flow to the heatex is upward

DeniseO30 · Oct 29, 2021

Kloudie this is a great example why it's always good to name the type engine model number being discussed. what is unique to one is not necessarily unique to another,
thank you so much for this! I had no idea about the thermostats yanmar used in their engines until now!
:beer:

DeniseO30 · Oct 29, 2021

dlochner said:
I'm sorry, but could you explain what a "raw water cooled exchanger engine" is? I've not heard this term before. I know what a raw or seawater cooled motor is, and I know what a freshwater cooled motor is, and I know what a dry stack is.

Seriously, the forum sees many people who have incorrect, partially correct or no understanding of boat systems. It is the culture here on this forum to share our knowledge. Many of us are willing to take great effort to provide correct and accurate information, that's why Tim asked his question here and he's a knowledgeable guy. For the question he asked and the manner in which he asked the question, the particular brand of motor is not all that relevant. It would make no sense at all to advise someone to add AF to a raw or seawater cooled motor, you might just as well pour a gallon jug of AF into the water.

Tim's friend, the one he is asking about, clearly doesn't know what AF does and does not understand the chemistry of cooling liquids at even a most basic level. The longer answers given provide him with explanations in different manner so that he can help his friend stop wrecking his expensive motor.

At a personal level, understanding why and how something works is far more valuable to me than simply knowing a fact, it is far more valuable to understand the benefits of and the mechanisms by which AF works than to simply know that I should put AF in my freshwater cooled diesel.

If you should find my sometimes lengthy responses annoying, irrelevant, or "mansplaining" then feel free to skip over them. No need to read them and complain.

Did not complain was being light-hearted I'm sorry humor escapes you... BTW you still haven't named the engine you were talking about

dave_and_dd · Oct 29, 2021

Additionally, in my limited experience, running an engine without a thermostat takes longer to come up to operating temp, is not good for the engine, and can increase clogging of the mixing elbow.

Dave in Charlotte Harbor

Ralph Johnstone · Oct 29, 2021

DeniseO30 said:
Yanmars of course are notorious for exhaust elbow problems

How can you say that ....................................

?

DeniseO30 · Oct 29, 2021

Ralph Johnstone said:
How can you say that .................................... ?

View attachment 199629

Pictures like that come up a lot discussing Yanmar ex elbows! Thing is it, can be cleaned from the exhaust outlet side but you need some pretty heavy duty steel brushes and acids but it's worth trying to keep them clean for what these things cost!

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