Closed cooling question

"on a 1993 mercruiser 454 in a

"on a 1993 mercruiser 454 in a 76 searay, is it possible to do away with the closed cooling system? the boat will only be exposed to fresh water.."

"yes you can, even if only use

"yes you can, even if only used in fresh water, the boat will hold a little more value and the engine will last longer, and you wont have to worry about the engine block cracking and costing you $5000 + to replace it.

but if you dont want it.. send them to me here in NH.. I'd love to put them parts on my engine."

"Kevin, I'd be careful.

"Kevin, I'd be careful. Big blocks have closed cooling systems that use anti-freeze. Anti-freeze has better heat transfer properties than water. That means anti-freeze will cool the engine more efficiently than pure water.

Anti-freeze will also inhibit corrosion of the block and manifold(s), and as the name states will prevent the engine from freezing should you live in a climate where it gets cold enough to freeze in the winter.

I have to disagree with Brian, your engine will not last longer given the additional risk of over heating or freezing, nor will the re-sale value improve. People pay more to have closed/fresh water cooling on marine engines."

"Sorry I guess I wasn't cl

"Sorry I guess I wasn't clear, and my light, gentle sarcasm didn't come through enough.. ( not so much a bad thing )

I'm ALL for keeping the Closed Cooling system.

I didn't want to say it, and to be nice it wouldn't be smart to remove the closed cooling.

And keeping the closed cooling, as Henry said, is more efficient in cooling, thereby keeping the engine temp more stable and more fuel efficient than without ( as fuel efficient as a big block can be.. )"

"[b]quote: "is it possible

"quote: "is it possible to do away with the closed cooling system?"

For every reason that you would have to remove a closed cooling system, there are likely ten reasons in favor of keeping one.
Removing a working system is a very counterintuitive way of thinking, IMO!

."

"Kevin,

I am not sure if th

"Kevin,

I am not sure if this can be done or not, but the specific heat capacity of fresh water is a fair amount better then ethylene glycol (is that what your running?).

Water has a specific heat of 1, while that of ethylene glycol at 50% mix is about .80 to.85 and with 100% mix about .60 to .65, with running temps of 120-160 degrees. Of course, the benefit of ethylene glycol is the corrosion protection.

Fresh water also should be much lower in temp then the return of the closed system, so you would gain heat capacity there too.

Some other "boat guys" can probably answer better if you can do this or not. I bet Kghost or Guy has done something like this?

Thanks,Jasson."

"That is a moot point as a int

"That is a moot point as a internal combustion engine needs a certain amount of temp to run correctly and not need excess fuel.

Virtually all fresh/raw water cooled engines run a 143 degree thermostat. Virtually all closed colling systems run a 160 dgree thermostat.

The reason for the 160 degree thermostat has something to do with the antifreeze in water mix I think but I will confirm tomorrow and repost. Definatly there is a certain temp requirement for something to occur.

So as we may all know from years gone by, before the advent of smog and emissions almost all engines ran a 180 degree thermostat. and of course virtually all marine engines do not have any smog or emission controls.

There is a reason for this, engine oils, fuel mixture/atomization and a whole lot of R&D says that they like/have been designed around temps between 150 and 190. (water/coolant temperature)

I am no scientist nor do I have the facts (right now) but in a nut shell that is it.

So the need for better cooling is not justified by changing a perfectly good cloosed cooling system over to fresh water cooled unless it is for a personal choice or convienence only.

the closed cooling system is to prvent salt water intrusion into the block for longevity reasons only. Not because it keeps it warmer or cooler.

If it does over heat, find the problem.

anyway that is my opinion."

"Oh and I wil repeat Brian,

"Oh and I wil repeat Brian,

If you do remove it feel "free" to send it over to one of us. Brian lives close but maybe my place may be the best location................LOL"

"Jasson,

Anti-freeze, or en

"Jasson,

Anti-freeze, or engine coolants, containing ethylene glycol not only have a lower freezing point, but also a higher boiling point.

The heat transfer characteristics of a material in the liquid state are superior to that of the same material in a gas state (all other factors being equal). Thus a liquid that remains a liquid longer will be more efficient at removing heat from an engine block."

"[b]Ditto Henry's comment!

"Ditto Henry's comment! He is correct about the E/G!

Before chastising me for this, hear me out please!
Somewhere in the mix years ago, the ethylene glycol engine heat exchanger systems became known as "Fresh Water Cooling". Perhaps this occurred during the advent of what I call, a "Closed Cooling System", whereby salt water boats were being fitted with these to protect the engine not only from freeze damage, but for eliminating salt water corrosion and extending the life of the engine block and cylinder heads!

To me, the term "Fresh Water Cooling" (one of my little pet peeves) is a misnomer at best! Believe me.... there is nothing fresh about Ethylene Glycol and H2O...
Ya can't drink it... ya can't bath in it!
But the industry ran with it!

So, whether correct or not, I always refer to these as a "Closed Cooling system" or a "Closed System". (yes, I'm anal about this)

As for thermostat rating...... any open, or "raw water cooling" system that is in salt water must run the cooler 145* stat. This is due to salt crystallization that occurs when temps exceed this heat range. This crystallization adds to the build up of corrosion on the internal cooling jackets of cast iron engines and exhaust system, and eventually limits the ability for heat transfer.
So this crystallization is a concern in this area as well.
I'd recommend keeping the temps low if in salt water. Most good and thorough OEM manuals will give this recommendation as well.

Conversely, any open system that is used in lake, river or so called "fresh water" can use the warmer 160* and/or 180* stat. Engines prefer this temperature over the cooler temps.
I'd recommend running the warmer stats if you are not in salt water!
Any "Closed System" will be best if you keep engine temps between 160* + and 180*.

Circ pump: The engine's "Circ" pump (the belt driven factory engine pump) is still using the same HP to operate this pump, whether the system is a "Closed Cooling System" or a "Raw Water Cooling" system..... the engine load is the same.
IOW's, Both systems use the Circ pump for circulating the coolant through the engine.... whether the coolant is E/G or river/lake/sea water.
So neither has a benefit over the other in regards to this, IMO!

Now we factor in what Henry just tossed in the mix, and it only makes sense to stay with a closed system if it already exists.
Personally, I'd like to see ALL BOATS equipped with a closed system.
The draw-back would be, the shops would not be replacing engine$ in the $pring time!


Side note: Should you remove the "Closed Cooling" system, this engine circ pump now needs to be replaced with a marine version that has a different shaft seal AND has the bronze impeller.
The sea or raw water pump can likely remain the same.

A tip for some:
Pull your raw water pump impellers for the winter, and leave your drives fully DOWN for the duration as to protect your drive bellows.... you will extend the life of them.

."

"There was no disrespect ment

"There was no disrespect ment with my post above, BUT Henry your quote as it is typed:

"Anti-freeze has better heat transfer properties than water. That means anti-freeze will cool the engine more efficiently than pure water."

is wrong. Period! And think what you want, that is the science! That is the ONLY ONLY ONLY reason I posted my comment. BECAUSE, if I read that and didn't know better I might think that was the truth, which leads to a lot of bad information.

I come here (or any website like this) to learn more, and would hope others would like correct information.

Of course, I agree that eth. gly. changes the bp of water for a cooling system (it says that on the jug, ha-ha), but that was not originally mention. The original comment made no mention of change of state either. BUT then you deal with latent heat also, but that is another topic....(Mr, Boyd, There are other people that have engineering degrees too! but maybe not masters.)

I would like to think we would use this site to help make us smarter.

Poor Kevin, I guess this was not what you were asking for?

Jasson."

"Jasson, When discussing the t

"Jasson, When discussing the topic of a Ethylene Glycol in a Closed Cooling system, whether boat, car or truck...... why would anyone want a comparison between H2O and E/G and the heat absorbing qualities, or properties, between the two...... AND at the engine temperatures that we are discussing?
The E/G clearly outperforms H2O given the pressure, bp and temperature that one would want it to perform well at within the engine's system.

If you wish to examine this on the level of chemistry, and at lower temperatures, the info suddenly looses it's place and value here in a marine forum related topic.
And then to suggest that Henry's comment leads to bad information???? Hmmm.
Do you know something about E/G vs H2O as a coolant that the Big Three should have known years ago?

Maybe being "smarter".... (or as an intelligent person may say..... "more intellectually advanced") ...... would cause one to refrain from posting such a comment regarding a marine engine heat exchanger as the topic.

Hey, lighten up.... I'm just having some fun with you!!!!!
"

"And I'm just having some

"And I'm just having some fun with you. The science is the science!

Your right that there is no comparison, eth gly is right for a closed system. BUT, that was not the statement

AGAIN.......to make a broad statement that :

"Anti-freeze has better heat transfer properties than water. That means anti-freeze will cool the engine more efficiently than pure water."

is not accurate!

Then why aren't all boats closed system cooled? My engine is a "Big Three" fresh water?

If you want to change the question, then leave room for the answer. "

"It's now snowing here, gl

"It's now snowing here, glad I didn't use my boat this year.

Kevin, don't let this deter you from posting further questions, if nothing it's a little entertaining, and somewhat educational on a few levels.

Safe Boating !!"

"OK lets say this.

CLOSED C

"OK lets say this.

CLOSED COOLING = E/G mix and a heat exchanger.

RAW WATER = NO E/G or heat exchanger.

That statement of the temp bieng designed to keep salt from crystalizing is exactly what I could not remeber last night in my earlier post, Thanks.

Some facts..

All marine engines either closed or raw have standard marine engine water circulating pumps with bronze impellers and appropriate seals to the best of my knowledge.

If not then I would suspect someone swapped it out at some time.

There is no real reason for a marine engine manufacturer to make this change. they all carry a marine rating.

Also I would not reccomend anyone running a 160 or 180 thermostat in a raw water cooled angine.

A 180 degree thermostat would result in the engine running at ~ 220 whne running hard at near full throttle for any length of time.

IE: when a 143 degree boat is run hard the temp typically reaches ~ 180 degree.

That is my opinion...........

Science !!! who needs stinken SCIENCE!!

School of HARD KNOCKS!~!!!!!!!"

"Stinken

Dutch Verb - to st

"Stinken

Dutch Verb - to stink

German Etymology - Old High German - stinken

Pronunciation ˈstɪnkən

Verb stinken (strong, third-person singular )

simple present stinkt

past tense stank, auxiliary haben,

past participle gestunken)

(intransitive) to stink

The internet can just be so darn helpful.."

"lively discussion. the closed

"lively discussion. the closed system stays. i worked in a radiator shop for a number of years. before 100,000 mi antifreeze or the 50/50 mix. every car we temperature checked. a particular car with straight anti freeze ran, at idle, about 5 degrees cooler with appx 40% water in the system. that was just my experience. i am in no way trying to match wits with anyone."

"Gotta add my two cents on thi

"Gotta add my two cents on this one.

Jasson is right on about the science; specific heat is specific heat and water is superior with that property to anything else most of us can afford.

When it comes to selecting parameters for the cooling system, one has to "balance things". As noted, the temperature range of operation is a big factor as is storage temp. add to that corrosion resistance and the efficiency of the engine versus its operating temp and you can readily see the Marine Engine Designer has some tough choices. Add to that the Corporate Desire to minimize Warranty claims while delivering a reliable product and the choices get harder.

The engine is most efficient at internal temps above 180. The tendency of minerals to precipitate out of the cooling media onto the cast iron increases with temperature. Add the variable of mineral content across the US, let alone the world, and most OEMs select the 140 range for the raw water systems. On top of that, the raw water systems lack the benefit of being pressurized, in a controlled manner, so lower temps are 'better', again.

The bottom line is there are many decades of track record on this topic. It is all supported and reinforced with science (or engineering if you prefer). I don't believe anybody that has contributed to this "collection of knowledge" would want to eliminate their closed cooling system."

"Personally, I just stick with

"Personally, I just stick with the bottom line. Closed Cooling systems help with longer engine life and better resale value. Most importantly, it make the engine look bigger and tougher and meaner and more expensive.....particularly if you are a "show-off".......like me."

"(This is all typed with a

"(This is all typed with a smile on my face!)

I did not make my original post lightly. I also directed it toward the author, since that should be proper etiquette (but I guess that is out the door now,ha). With facts to back it up the statement.

I am (was,ha) an engineer and worked in the paper industry for 15 years. I was a salesman selling a product that required water cooling (open and closed systems). In that last 5-7 years, we were removing water cooling (in some cases) and replacing with different methods of eth gly closed systems. I talked water cooling, heat transfers, thermal imaging with $60k cameras, etc, every day. The failures always came back to the basics, so I have been to your school too Kghost!

I am currently a small business owner with many (37 actually) refrigation units (coolers, freezers, etc), and am taking classes to get HVAC cert. (I'm a hands on person), with a lot of information on the specific heat of water.

I dont know much about boats (and learning), but I do know some about water cooling. I do know more then, "eth gly tastes sweet to animals."

My apologies to everyone I ment no disrespect, just thought it might be a piece of information that would be helpful.

(let the fireworks begin, haha)
Kghost-My 4.3L runs a 160 t'stat, and running temp is 175 all day long. Maybe you should call Merc and have them do a recall! (I am physically laughing typing that, so please take that in fun. I have a lot of respect for your knowledge, and you have prob forgotten more then I will ever know!)

Again, I come from growing up with a boat that was a 4 cyl, merc alpha 1, that for 12 years of ownership we ONLY changed the oil once a year. Never one problem. I miss that boat.......

"My pencil is on my desk, teacher!" "

"Kghost:

"IE: when a 14

"Kghost:

"IE: when a 143 degree boat is run hard the temp typically reaches ~ 180 degree."

Mine never gets above 150 F. even when I make a 10 mile run at 4,000 RPMs."

"Most are not as well kept as

"Most are not as well kept as yours.......

Mine actually reaches around 170 ish when trimmed ALL the way out going for the max, 4700-4900 rpms........I just cant seem to get beyond 53 mph with a aluminum prop.....and it gets warm.......


I should have been more specific and sais under wide open throttle or close to it for long periods of time.

When trimmed as far as it can there is some loss of water from the outdrive and also at rpms above 4500 that motor makes some heat!!

I was also just making a speculative point.

Jason

If you run a 160 degree thermostat then I would say you have a CLOSED cooling system.

I personally am not aware of any nonclosed cooling systems that run 160 thermostats.

If so please give the year and engine serial number and I will look it up and confirm.

as stated the RAW water does not want above certain temps to keep the salt water from crystalizing.

If your engine is RAW water and has a 160 and it is not what is called for then someone put the wrong one in!"

"Yikes, what a tough crowd.

"Yikes, what a tough crowd.

Here is what I said:

"Anti-freeze has better heat transfer properties than water. That means anti-freeze will cool the engine more efficiently than pure water."

Here is the basis for my statements:

Mr. Thomley is correct; water with a specific heat of 1.0 is more efficient than anti-freeze with a specific 0.8 as a heat transfer medium.

Anti-freeze has a higher boiling point than water (the 'better' heat transfer property I was referring to). That is significant because steam (the result of boiled water) has a specific heat of 0.48 and that is much worse than anti-freeze's 0.8.

I think many would agree that the term efficiency when applied to engine cooling (as I did) would mean just that; cooling the engine. Yes, water is more efficient than anti-freeze at absorbing heat. But only until it starts to boil off. So in a situation where the combination of engine temperatures, coolant volume and velocity could create water boiling, anti-freeze becomes more efficient at cooling the engine because while being a less efficient heat transfer medium than water it is a far better medium than steam, or a water steam mixture.

Big blocks are generally put in big heavy boats. Our 496 pushes around a 12,000 cruiser at 20-25 knots at 3600 rpm as an example. The amount of energy required to do that and the resulting waste heat is significantly greater than a v-6 pushing a 3,000 pound bow rider to the same speed. That is why some boat engines can get away with raw water cooling and others can't.

Since we were talking about big blocks in the first place, I didn't think more elaboration was necessary. My apologies for not being clearer."

"Henry - your last explanation

"Henry - your last explanation helps but fails to account for the effect of pressure in the system, above atmospheric, which helps both 100% H2O and a 50/50 system.

Technically, you're still incorrect; heat transfer is quantified by specific heat. Here, science and math intertwine; since 1 is bigger than zero point anything, the point is made.

Here's a classic thermodynamics question for the interested to research: "What transfers more heat, a hot medium or a cold medium?""

"This has actually been a grea

"This has actually been a great post, people coming form different background with concerns for doing the proper maintenence.

Again Mr. Boyd, there was no disrespect. I'm sure with your ISO involvement and Masters Degree, you are much smarter then....("is this me or I, now this is going to make me look really dubb) I!

P.S.- You need to update your website. "

"RE:"Science !!! who needs

"RE:"Science !!! who needs stinken SCIENCE!!
School of HARD KNOCKS!~!!!!!!!"

Science reduces, not eliminates Hard Knocks. :- )

Re: "was (ha) an engineer" I'm a former engineer (BSEE and 2 patents)... My job got offshored...Still looking for that higher paying job I can re-educate myself for that was alluded to by BOTH the presidential candidates last election. Anyone out there know of one...let me know "

"[b]Quote: A 180 degree thermo

"Quote: A 180 degree thermostat would result in the engine running at ~ 220 whne running hard at near full throttle for any length of time.
IE: when a 143 degree boat is run hard the temp typically reaches ~ 180 degree.

If your temps are going much beyond your stat rating, then you may have other issues that need to be resolved, IMO.
Whether M/C, Volvo Penta or OMC.... it should make little difference if all else is working as it should be."

"It is more constructive to th

"It is more constructive to think of a T'stat's job as establishing as rapidly as possible and then maintaing the minimum temp at which the engine runs, not the max temp.
The max is limited by the (functional) capacity of the cooling system and the engine load."

"Robert.... certainly said a l

"Robert.... certainly said a little differently than I would have..... but yes, I agree!

The stat's job is to "hold back" coolant and release it on an "As Needed" basis as temperature is sensed!
The stat's ability to allow enough flow is very adequate providing that the Heat Exchange is adequate! (sea water flow, impeller condition, exhaust man condition, lake/river water ambient temp, hoses, heat exchanger, and so on!)
Not necessarily the other way around unless you have a failing thermostat!

So you likely have something else wrong if your stat will not maintain temp within reason.
."

Do water and oil mix? Wouldn&

Do water and oil mix? Wouldn't oil be better in a closed system than water/EG? What's the heat transfer parameter of cast iron vs aluminum? How many thingies in a doowa? Ta de ta da they're coming to get me ha ha ha ha.

He said "darlin' I can't live without you".
She said "prove it".