keel cooler coolant filtration

I thought that I had all bases covered. I then discovered that the construction vehicles are all using filters in their closed coolant systems (keel cooling).......

A bit of googling:...all articles are pretty much agreeing that these coolant filters are as important for the longevity of the engine as the fuel filtration and fuel polishing...

another search: unable to find any filters that relate to keel cooling, only found filters for industrial cooling systems and trucks with air cooling (small amount of cooling liquid).

So the questions are: are these filters relevant for a keel cooled engine, what brand/filter are recommend and how would these filters be installed on a keel cooled engine?

Singleprop said:

So the questions are: are these filters relevant for a keel cooled engine, what brand/filter are recommend and how would these filters be installed on a keel cooled engine?

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The prudent mariner will refer to the manufacturer's documentation. Some filtration systems add supplemental additives to the coolant, some manufacturers strongly oppose supplementing what is already in the coolant product they recommend using. Different designs, different metals, different internal conditions and localized temperature gradients require different treatment - or not.

The existence of a keel cooler doesn't change much besides the plumbing. If the manufacturer of the engine doesn't say anything other than use clean water and a non-corrosive antifreeze then you can pretty much do what you want. Just be aware that most filters contain a supplemental cooling additive and that product may or may not be compatible with the coolant you are currently using.

There are ways to test the coolant for problems, buy the kits and learn to use them.

Hi Rick, your reply is in line with most marine forums, they seem to ignore that there are other issues than the coolant mixture.. like rust flakes in the cooling pipes. The manufacturer recommendations has to be followed as much as possible but when using a welded keel cooler this is seldom possible.

I would say that since our engines are twins of the industrial engines, then our engines should have the same generic illnesses and therefore this should be a concern.

What solutions are out there? Delfin usually has a good answer....

Singleprop said:

... they seem to ignore that there are other issues than the coolant mixture.. like rust flakes in the cooling pipes.

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That should be less a problem than bird nests in the masthead light. Why would there be "rust flakes in the cooling pipes"?

If you homebuild a keel cooler out of steel pipe you really ought to have sense enough to clean it out before filling the system with coolant. A proper coolant mix will prevent corrosion in the pipe ... that is a major part of the coolant's job anyway.

High pressure team plants require water cleaner and more pure than anything you can probably imagine and that water moves through good old fashioned steel pipes at elevated temperatures for years without the system collapsing from "rust flakes." It really sounds like someone has spent a bit too much time yakking and drinking beer on the dock and not enough studying real life applications.

rust flakes ARE in the system because the builder did not cover the build after welding it...........so there is no question that I need the coolant filter system because of this....

Singleprop, I recently purged my system with a vacuum cleaner and replaced the t stats. A little rust color but over all not to bad. I would just dump your old coolant replace. Think about the filter for a minute. If you install one and it clogs up your going to overheat, yes no. I would purge it until you have clean fluid.

I'm with Swampu on this one ..... just flush your cooling system out if you're that worried .... a few flakes of rust wont stop you in the water , but clogged filters will .

... but you will need to wait for Marin to weigh in on this as usual.

As fas as I can evaluate they are using are by-pass filters, which only cleans a portion of the fluid.
A blocked bypass filters would not be a show-stopper while a full flow filter would be a show-stopper.

Singleprop said:

rust flakes ARE in the system because the builder did not cover the build after welding it...........so there is no question that I need the coolant filter system because of this....

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There is no question that you should chemically clean the piping and use a corrosion preventative coolant.

It is not difficult to flush and clean such a small system. The chemicals and techniques to do that safely and very effectively have been around for more than a century. If you are worried that much about "flakes" use a strainer, not a filter but simply cleaning is a no brainer.

If it is a steel pipe system, flush a bit of dilute muriatic through it, rinse with a weak Drano solution followed by clean water, add coolant and call it done.

that is good news.

Have any of you read the discussions in the truck forums about these filters and why they use them?

Basically, dirt in the coolant clogs the passages inside the engine. In time this can create wear and hot spots in the engine, for example around the wet cylinders, with serious consequences.

To me, it seems that these filters could be a cheap insurance

How does a by pass filter work? Is there a valve you must turn or is the pipe bigger than the main pipe to account for pressure rise because of the filter? I think of the extra added on system as a liability, any time you add a T or an elbow or rubber boot to connect stuff your adding more point of failure and pressure to the system. I have 4 rubber connectors in my whole system

Singleprop said:

Have any of you read the discussions in the truck forums about these filters and why they use them?

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Oh, yeah ... those guys don't buy anything that isn't necessary.


Perhaps if you read the threads on oil change frequency and substitute coolant for oil in each post the "insurance" argument might hold more water.

Singleprop said:

I thought that I had all bases covered. I then discovered that the construction vehicles are all using filters in their closed coolant systems (keel cooling).......

A bit of googling:...all articles are pretty much agreeing that these coolant filters are as important for the longevity of the engine as the fuel filtration and fuel polishing...

another search: unable to find any filters that relate to keel cooling, only found filters for industrial cooling systems and trucks with air cooling (small amount of cooling liquid).

So the questions are: are these filters relevant for a keel cooled engine, what brand/filter are recommend and how would these filters be installed on a keel cooled engine?

Click to expand...

Boiler systems use bypass filters that should work. The steel pipe in your system is just an extension of the water jacket, and both are susceptible to rust. Of course this can be flushed and rust prevented with appropriate coolant, but I can't see where a bypass filter wouldn't be at least a theoretical improvement over not having one. This is kind of the same as the argument around oil bypass filters. I understand some folks think they are pointless, although I have yet to hear a convincing argument that oil filtered to a couple of microns isn't an improvement over oil filtered to 30 microns.

Ok mine is copper 4 runs of 8 feet 1 inch copper mounted on the bottom of the boat then through hulls to the water pump , I used Air preasure and pushed all the coolant out this winter then refilled it and ran it in the spring, What if anything should i do to protect the inside and the out side is raw and has a Zinc on it . I was told not to paint it with anything it cool's fine at it is set up. But i am always looking for additional information or things i should do.

honeybadger said:

Ok mine is copper 4 runs of 8 feet 1 inch copper mounted on the bottom of the boat then through hulls to the water pump , I used Air preasure and pushed all the coolant out this winter then refilled it and ran it in the spring, What if anything should i do to protect the inside and the out side is raw and has a Zinc on it . I was told not to paint it with anything it cool's fine at it is set up. But i am always looking for additional information or things i should do.

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I don't think you need to do anything other than keep the coolant fresh. I kind of like the extended life coolant, which is more expensive, but lasts 5 years (according to CAT). Since you don't have the steel runs of half pipe clean coolant seems to me to be sufficient.

This is what my keel cooler looks like....

RickB said:

There is no question that you should chemically clean the piping and use a corrosion preventative coolant.

It is not difficult to flush and clean such a small system. The chemicals and techniques to do that safely and very effectively have been around for more than a century. If you are worried that much about "flakes" use a strainer, not a filter but simply cleaning is a no brainer.

If it is a steel pipe system, flush a bit of dilute muriatic through it, rinse with a weak Drano solution followed by clean water, add coolant and call it done.

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like the old boiler screens I would guess...flanges with a screen between them for easy cleaning...some peopele add them downstream of their saltwater pump too to catch impeller pieces before they get into the heat exchanger tubes.

This is becoming a tempest in a teakettle ... just clean and flush the cooler and get on with life.

Your engines have steel and cast iron pipe and components, they are protected by the coolant and don't require strainers or filters or extraordinary efforts to function properly.

As far as truckers are concerned, I would take any advice they have about what you need with a small grain of salt. As far as "accessorizing" goes, they are the equivalent of SoCal debutantes. If there is a grain of truth and a layer of chrome involved, they will buy it and find a way to justify it.

RickB said:

This is becoming a tempest in a teakettle ... just clean and flush the cooler and get on with life.

Your engines have steel and cast iron pipe and components, they are protected by the coolant and don't require strainers or filters or extraordinary efforts to function properly.

As far as truckers are concerned, I would take any advice they have about what you need with a small grain of salt. As far as "accessorizing" goes, they are the equivalent of SoCal debutantes. If there is a grain of truth and a layer of chrome involved, they will buy it and find a way to justify it.

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It might be a small issue for you, but not for me....and the other replies are probably helpfull for others as wel....

What leads you to believe that your keel cooler pipes will continue to shed chunks of rust and scale after being properly cleaned and flushed? What makes it a large issue for you?

psneeld said:

like the old boiler screens I would guess...flanges with a screen between them for easy cleaning...some peopele add them downstream of their saltwater pump too to catch impeller pieces before they get into the heat exchanger tubes.

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That's an answer that I can use. Can you recommend a site that has pictures or info about this kind of screens?

RickB, your first reply was usefull, the rest of your posts are pretty useless and negative. In the interest of keeping this thread usefull for others that might have the same problem as I have, I would appciate if you do reply any more to this thread. I decide when I have enough information to make a decision, not you.

Singleprop said:

RickB, your first reply was usefull, the rest of your posts are pretty useless and negative. In the interest of keeping this thread usefull for others that might have the same problem as I have, I would appciate if you do reply any more to this thread. I decide when I have enough information to make a decision, not you.

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I will respond to any post I choose thank you. If you don't like what I write, ignore it.

I hope that reality based information is useful to others who don't succumb to the sky is falling approach to boat maintenance. If you keep fishing you will undoubtedly find someone who will suggest you waste your time and money in some fashion that appeals to you.

Since you seem to have some concern for providing others with "usefull" information, tell them what it is you are so worried about and why you believe your keel cooler will continue to shed crud? What part of cleaning it properly is so offensive that buying filters and screens is a better alternative? An explanation of that would be very useful to many of us.

Singleprop said:

That's an answer that I can use. Can you recommend a site that has pictures or info about this kind of screens?

RickB, your first reply was usefull, the rest of your posts are pretty useless and negative. In the interest of keeping this thread usefull for others that might have the same problem as I have, I would appciate if you do reply any more to this thread. I decide when I have enough information to make a decision, not you.

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sorry no....I've heard that some just make their own out of 2 flanges and a screen.

but I think Rick is right...clean and don't worry...inspect regularly...

As I said Rick. I decide when I have enough information. You don't have to call a stop to a thread just because you have passed your information and think this is the only valid answer. There are OBVIOUSLY others that can contribute. I am pretty sure that others will decide for them selfs when they have enough info.

You seem to have forgotten who told who to stop posting.

This is childish. Thanks.

I'm of the opinion that it's pretty hard for dirt to get into a closed system and once it's properly flushed and filled with the proper coolant, there should be no rust, so I can't see any value in running the coolant through a filter or screen.

We don't commonly see coolant filters on cars, trucks, or boats. If they were needed, they would be common.

on modern diesels they are a little more common as the cavitation problem has became a bigger issue...so coolant filtration to keep the silicate levels good have become more popular.

the previous owner/head mechanic of the assistance towing fleet I work for even put them on the gas engines.

psneeld said:

on modern diesels they are a little more common as the cavitation problem has became a bigger issue...so coolant filtration to keep the silicate levels good have become more popular.

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A more reasonable approach might be to change to a silicate-free coolant such as CAT's ELC extended life coolant. Such a choice would eliminate concerns about high silicate levels, problems with nitrates, and the added expense and complexity (read that as point of potential failure) that are associated with adding another component to the engine.

I know it is not much fun and doesn't provide anything in way of bragging rights or bling, but simply cleaning the cooling circuit, maintaining the pump, and using the proper coolant is about all you have to do to obtain long and trouble-free life from the jacket water cooling circuit of a recreational boat engine.