Flushing the coolant/antifreeze part of the cooling system.

[sv.antea]

Looking for a product or chemical to flush the coolant /antifreeze part of the cooling system on Kubota based engine, block, pump (aluminum), exhaust manifold and all. Most internet discussions revolve around the raw water part, the inside of tubes in the heat exchanger. I used Barnacle Buster with good success to clean out the tubes in the raw water part of the heat exchanger (have lots left over), but the engine shows evidence of past overheating and salt water intrusion into the coolant/antifreeze circuit (form busted heat exchanger in the past?) - same chalky deposits.
Previous experience: A mysterious Yanmar overheating turned out to be caused by a thin film of something that came out of the antifreeze, coating the outsides of the heat exchanger tubes. Just read an article about the exact same thing, solved by immersing the whole heat exchanger in a bucket of something. Can't find it now. I am not about to take the heat exchanger out again. No way to see if this heat exchanger has the same problem, I just guess it does. Thanks Stan

[El Pinguino]

Interesting.... I have just been investigating solutions to a very similar problem that I have...

Found this ... https://trac-online.com/product/trac...er-®-ready-use

Doubt I will be able to find it in Chile... but who knows...

Hope this helps

Ping

[Lepke]

I use Rydlyme for both. It dissolves rust and other corrosion. When I had a yard I fixed a number of overheating engines where the owner or another yard never bothered to flush the coolant side, just changed parts - thermostat, pump, heat exchanger.

I'd use a couple gallons of Rydlyme (depending on engine size) and water, idle the engine for a couple hours as Rydlyme recommends. And in most places the Rydlyme and water can be dumped over the side. Never failed for me.
You might want to remove pencil zincs or aluminum. It's ok with an aluminum block and other parts made to run in coolant.
Rydlyme is usually on ebay or Amazon and commercial marine stores.

[thinwater]

[I spent a career in the business of making glycol (designed one of the larger plants) and formulating engine coolants (was active in standards committees).]


The deposits are most likely either silicate or calcium from hard water. Does the engine coolant contain silicates? Have you used tap water for blending or topping off, or have you used distilled water, as recommended in the standard? Though not well communicated, the standard for water used to blend AF is similarly strict to that used for battery top-off.


First, there are products used for this. I would NEVER use Rydlyme, since it is based on hydrochloric acid and it will be nearly impossible to flush to low enough levels to meet the engine coolant standard. Barnacle Buster, based on phosphate, is a far smarter choice for an engine. Rydlyme is fine for raw water systems, since it will be flushed in use. But I would NEVER use it on glycol cooled engine.


Second, you will need to flush many times. In general, engine manufacturers are not happy with flushing chemicals, since it is very hard to flush them well enough without disassembly. As a start, flush until the flush water is no longer acidic (measure it), then flush once with distilled water. That is what the spec calls for.

[a64pilot]

To really flush it all out, I run the engine with the drains open and a water hose that I control the flow to keep the system full.
I remove the thermostat to ensure full water flow without any heat, cause of course if your draining a gallon or two a minute and replacing it as fast as it drains, it’s not even going to get warm.

My guess is silicates too, and I’m not sure they are very easily removed. I dislike silicate containing anti freeze based on what it has done to some water pump seals in the past, and it’s just not needed.

Although I am no antifreeze expert I seem to gravitate toward HOAT anti freeze now where OAT used to be my favorite, and I never had any problems, but apparently many did.

[ggray]

I hadn't heard of OAT or HOAT, so looked them up.

I read that HOAT has added silicates, FWIW.

[thinwater]

Originally Posted by ggray

I hadn't heard of OAT or HOAT, so looked them up.

I read that HOAT has added silicates, FWIW.

The levels of silicate in NOAT and OAT coolants is 10-20 times lower than in conventional coolants. They learned that just a trace of silicate protected the hoses against damage from the OA.


You will not get silicate dropout with a HOAT coolant.

[ranger58sb]

Originally Posted by sv.antea

Looking for a product or chemical to flush the coolant /antifreeze part of the cooling system on Kubota based engine, block, pump (aluminum), exhaust manifold and all.

Cummins recommends the Fleetguard RESTORE product for periodic flushing of coolant systems in their diesels.

Don't know if that'd make it appropriate for a Kubota, though.

-Chris

[bailsout]

Freezing and overheating has never been a problem in the climes we sail. My buddy always uses “ emulsified oil” and distilled water. Never had any coolant system problems.

[a64pilot]

The old way to flush a system was a strong acid, followed by a neutralizer.
I just don’t find that necessary though unless you have a very, very rusty system.
When I bought my boat, it had light rust. A little rust sediment in the expansion bottle etc.
A vigorous flush with just clean water seems to have removed it all, of course you have to remove the expansion bottle and clean it out in the sink with a bottle brush.

[sv.antea]

Thanks to all of you for your suggestions. This engine is on friend's boat (he just bought) and he did not experience overheating. I had the engine out for few months for the aforementioned engine room remodeling and just did not feel like putting in fancy antifreeze without some kind of flushing prior. The owner already ordered Track's Descaler product, so we will use that and follow the instructions.
My own boat has a Universal M25, another Kubota, which I have installed in 1982, I am on second heat exchanger, but I never flushed the coolant circuit except with tap water. For better or worse, I never run the engine full tilt. I suspect it would overheat after 20 minutes. I will have some of the products (Barnacle Buster, Descaler, SewClean?) left over and will flush it belatedly one of these days.