Chemicals for flushing out cooling system of indirect cooled engine

[vyv_cox]

BTW, cavitation is not a Formula 1 thing, it is an HD diesel thing. The pistons slap the wall and cause cavitation on the reveres side. In general, it is a problem only with wet sleeve engines that are run at high load factors. OA coolants do better than inorganics. It is a very uncommon problem in recreational boats, but not unheard of and is considered in the coolant spec.

I have many similar photos from engines all around the world, mostly large. Gas engines, diesel generators, etc. Some in Oman, where they chose not to use any coolant other than water, were particularly bad.

 

[Dull Spark]

Could Vyv please comment on my original proposal to drain down and flush with washing soda solution before draining it all out and refilling with proper antifreeze/coolant.

I'm concerned about the chemistry of washing soda and the engine/heat exchanger/calorifier internals.

Much appreciated.

 

[vyv_cox]

Could Vyv please comment on my original proposal to drain down and flush with washing soda solution before draining it all out and refilling with proper antifreeze/coolant.

I'm concerned about the chemistry of washing soda and the engine/heat exchanger/calorifier internals.

Much appreciated.

Sorry, I am not qualified or experienced in this technology. You might like to read this All You Need To Know About Coolants - Coolants Technology, Function, & Applications - Valvoline™ Global Europe - EN to understand more about it.

Googling gives me many DIY proposals including acids, alkalis and others. I doubt that any of them has much scientific basis. I have checked the SMS sheet for Valvoline cooling system cleaner, which tells me that it comprises ethylenediaminetetraacetic acid, tetrasodium salt in diacetone alcohol, definitely more complex than washing soda.

I think in this case it might be best to use the commercial stuff. Do Beta have anything to say on the subject? Maybe VicS can offer more than I can.

 

[thinwater]

inhibitors are not needed in high temperatures....is that what you are saying?
My experience in high temperature countries was coolant (antifreeze/water 50/50 mix) was required and recommended by the car manufacturers.
I also found that the recommended mix had better cooling than just water.

In fact, plain water is a better heat transfer agent, with three caveats:

• You still need corrosion inhibitors. Actually, the requirement is slightly greater and the best chemistry slightly different, but the same idea.
• Glycol increases the boiling point of the coolant Thus, if you don't have glycol you need to either reduce the thermostat setting and increase cooling, or increase the system pressure. If you put plain water in a car you will likely boil over for this reason. But many industrial engines are adjusted for this.
• Sleeve cavitation can be more severe. Glycol reduces the collapse impact and the system pressure must be higher. It can be designed for.

Glycol is not vital for the cooling purpose, but the engine must be designed for plain water for it to operate correctly. So from a practical perspective, you always need 50% glycol engine coolant.

 

[billskip]

Glycol increases the boiling point of the coolant Thus, if you don't have glycol you need to either reduce the thermostat setting and increase cooling, or increase the system pressure. If you put plain water in a car you will likely boil over for this reason. But many industrial engines are adjusted for this.

That seems to coinside with my experience of problems with imported engines from cooler climates...

 

[Roberto]

I am thinking of washing soda because I don't want anything too aggressive attacking the copper heat exchanger.

Any thoughts or advice?

Fwiw, here in France it's common practice for that purpose to use a cheap commercial product named "lessive st marc", non-foaming detergent whose main active component is sodium carbonate deca-hydrated which I just discovered is also "washing soda"; maybe not chemistry Nobel prize but surely it's efficient and -given its widespread diffusion- no ill effects are known. One engine maintenance book says to drain coolant, fill with solution with product above, run engine under load for about 10-15 min, drain etc and repeat until the solution comes out clear. Rince a few times with fresh water, drain and fill with new coolant.

 

[thinwater]

Fwiw, here in France it's common practice for that purpose to use a cheap commercial product named "lessive st marc", non-foaming detergent whose main active component is sodium carbonate deca-hydrated which I just discovered is also "washing soda"; maybe not chemistry Nobel prize but surely it's efficient and -given its widespread diffusion- no ill effects are known. One engine maintenance book says to drain coolant, fill with solution with product above, run engine under load for about 10-15 min, drain etc and repeat until the solution comes out clear. Rince a few times with fresh water, drain and fill with new coolant.

This post relates to vehicles, but to some extent boats too.

----

People do all sorts of things, but flushing with washing soda is a monumentally bad idea for vehicles with aluminum radiators. So bad you can Google it.

A weak, inhibited citric acid solution, generally with some EDTA is the standard method and has been for decades. You are trying to remove lime and other metal hydroxides, so a weak acid is what you want. Lactic and citric are least damaging to aluminum. Oxalic acid is also used. If you want to use an alkaline flush (no good reason to IMO), then look for borate. It is less corrosive and more effective, and is, in fact, part of the additive package of some inorganic coolants.

No doubt that product is cheap. It will clean some gook, but it won't descale and it can corrode metals.

https://beta.lakeland.edu/AboutUs/MSDS/PDFs/3266/Super Flush Radiator Flush (Prestone) 10-21-16.pdf
https://clrbrands.com/CLR/media/PDF...-Radiator-Flush-Cleaner-SDS-16-Jan-2024_1.pdf
https://clrbrands.com/CLR/media/PDF...uty-Radiator-Flush-and-Cleaner-SDS-2-1-22.pdf
https://www.crcindustries.com/media/msdsen/msds_en-1006067.pdf

 

[Roberto]

No doubt that product is cheap. It will clean some gook, but it won't descale and it can corrode metals.

Just relating a very common practice, all possibly exceptionally wrong, except that practice has shown no ill effects, anyway whatever people do or don't on their engines is up to them. No idea about aluminium radiators (and google), it's usually an alloy with more diligent owners.


A friend of mine uses a dozen different chemical products to fit seacocks to grp (several different types of sealants, primers, washing agents, degreasing agents, etc), given his specific industrial background I am sure it represents the state of the art in seacock fitting. Why not, though maybe 99.9% of seacocks are fitted using one cleaning agent, some Sika sealant and job done.

 

[thinwater]

Just relating a very common practice, all possibly exceptionally wrong, except that practice has shown no ill effects, anyway whatever people do or don't on their engines is up to them. No idea about aluminium radiators (and google), it's usually an alloy with more diligent owners.
View attachment 176494

A friend of mine uses a dozen different chemical products to fit seacocks to grp (several different types of sealants, primers, washing agents, degreasing agents, etc), given his specific industrial background I am sure it represents the state of the art in seacock fitting. Why not, though maybe 99.9% of seacocks are fitted using one cleaning agent, some Sika sealant and job done.

I think the fallacy is obvious.

a. Many people smoke cigarettes without ill effect. doing something wrong does not always have obvious,i mediate consequences.
b. Most people never flush a radiator, probably with even less ill effect. That is what the industry has concluded.

Notice that the coolant manufacturers don't make flushing chemicals. That should be a big hint. Mostly, they are all bad, should only be used when required, and don't DIY the chemistry.

Something to consider. Coolants work, in a way, like anodizing aluminum. They create passive films. When you use a flushing chemical you corrode the film away, and the coolant has to passivate it all over again. One of the main problems with changing coolant types is that they form different films. Sometimes, in the process of replacing the original film with the new film, a strip or spot of no-film (active metal) is created and pitting starts. I'm retired, but I will still tell you that switching types is almost always a pointless risk with no upside.

Or smoke cigarettes because all the cool kids do. The doctors don't know a thing.

 

[Dull Spark]

Many thanks Roberto, Vyv and Thinwater

Apologies for the delay in giving feedback. I had trouble connecting while I was on the boat.

To drain the Beta engine down, I had to poke a small screwdriver into the drain line. The stuff that came out had sticky deposits that tended to bulk up and that had already blocked the relief valve overflow pipe several times. (Goodness knows what gunge like that does to the internal passageways!) It was opaque and rusty/terra-cotta coloured. It looked fairly dirty.

I took a sample and added some washing soda. Within a few minutes some silt had precipitated out on the bottom of the bottle. The sample above was no longer dirty and opaque, but bright and clear. It looked the same as fresh coolant.

The precipitate is not sticky and while still in the coolant sample, flows like sand in an hourglass. I've topped up the engine with ordinary tap water with just a weak mixture of the OAT coolant while I decide whether to go for a complete change and ordinary inorganic coolant (as sold to me by Beta.)

I think that whatever I do, I will take Roberto's advice and use washing soda for a first stage clean out. I'm reassured by the free-flowing silt that precipitated out. I reckon it would flow out of the drain line without clogging. Next stage should be another tap water flush.

Then, when the system is properly clean is to decide which type of coolant to use: organic or inorganic. I now have 5 litres of both. Any suggestions?