Coolant flush with Sodium Carbonate solution

[superheat6k]

I have found a service manual published by an industrial user of 6B series Cummins engines that sets out a detailed procedure for flushing the freshwater side of the engine using a solution of Sodium Carbonate ~ 500g : 22 litres of water.

Drain flush out, fill and then run the engine until thoroughly warm with the pressure cap off.

Then flush twice with freshwater, and repeat if water still running dirty.

Once clean & clear drain again then replenish with recommended 50% diluted EG based anti freeze.

I know mine need a good flush from the muck that came out when I suffered a brief overheat when the alternator pulley caused the belt to jump off.

Anyone done this ?

Anyone know a reason not to do this ?

Is there any reason NOT to use OAT anti freeze on a 1990 engine ?

Thanks

 

[VicS]

I have found a service manual published by an industrial user of 6B series Cummins engines that sets out a detailed procedure for flushing the freshwater side of the engine using a solution of Sodium Carbonate ~ 500g : 22 litres of water.

Drain flush out, fill and then run the engine until thoroughly warm with the pressure cap off.

Then flush twice with freshwater, and repeat if water still running dirty.

Once clean & clear drain again then replenish with recommended 50% diluted EG based anti freeze.

I know mine need a good flush from the muck that came out when I suffered a brief overheat when the alternator pulley caused the belt to jump off.

Anyone done this ?

Anyone know a reason not to do this ?

Is there any reason NOT to use OAT anti freeze on a 1990 engine ?

Thanks

Can't really think why not to use sodium carbonate. I assume that's crystals, eg washing soda which is the decahydrate, not soda ash ... there's a big difference.

Personally would probably use Holts Speed flush !

OAT antifreeze is not used in older vehicles because its not compatible with the old soldered copper and brass radiators. New ones are aluminium and plastic. At least that my understanding. Probably no reason not to use it in your Cummins, but why not use the conventional stuff ?

 

[superheat6k]

The stuff referred to was specifically Sodium Carbonate, which is Soda Ash ! Apparently a major ingredient in washing soda.

The stuff is cheap as chips, but not if it starts dissolving bits it shouldn't !

The reason for using OAT AF was the 5 year rather than 2 year additive package life.

 

[VicS]

The stuff referred to was specifically Sodium Carbonate, which is Soda Ash ! Apparently a major ingredient in washing soda.

The stuff is cheap as chips, but not if it starts dissolving bits it shouldn't !

The reason for using OAT AF was the 5 year rather than 2 year additive package life.

Soda ash is anhydrous sodium carbonate. Washing soda is sodium carbonate crystals, which are 63% water, Na₂CO₃.10H₂O

 

[thinwater]

OAT antifreeze is not used in older vehicles because its not compatible with the old soldered copper and brass radiators. New ones are aluminium and plastic. At least that my understanding. Probably no reason not to use it in your Cummins, but why not use the conventional stuff ?

No, no truth in that.,

There were some elasomer compatibility issues with 2EH, which have been resolved with small additions of silicate or other formulation changes. Not an issue with HD formulations anymore.

 

[thinwater]

The stuff referred to was specifically Sodium Carbonate, which is Soda Ash ! Apparently a major ingredient in washing soda.

The stuff is cheap as chips, but not if it starts dissolving bits it shouldn't !

The reason for using OAT AF was the 5 year rather than 2 year additive package life.

The recommended change interval in MARINE applications is still only 2 years because of concerns over slight seawater (salt) contamination. This is in the manual. 1 part per thousand exceeds the condemning limit for engine coolant.

(I developed formulations for many years)

 

[VicS]

No, no truth in that.,

There were some elasomer compatibility issues with 2EH, which have been resolved with small additions of silicate or other formulation changes. Not an issue with HD formulations anymore.

So no reason to use the conventional AF at all then ? even in older vehicles ?

 

[RichardS]

The recommended change interval in MARINE applications is still only 2 years because of concerns over slight seawater (salt) contamination. This is in the manual. 1 part per thousand exceeds the condemning limit for engine coolant.

I have to disagree with that analysis I'm afraid.

Firstly, the only source of contamination of sodium chloride into the coolant is from the heat exchanger. However, the coolant system is pressurised relative to the seawater system so unless the heat exchanger or exhaust system at or after the injection point is blocked sufficiently enough to raise the pressure in the seawater system above that of the coolant system there is not going to be any transfer. In any event, in that unusual situation salt transfer would be the least of your problems.

Secondly, let us look at the figures .... not to 100% accuracy but close enough. My coolant system is 8 litres including the calorifier and expansion tank. A concentration of 1 ppt is equivalent to 8 grammes of salt. The concentration of salt in seawater is about 3.5% so the amount of seawater needed to contain 8g of salt would be around 230 mls. Now, in the case of my engine, 230 mls is the difference between the normal level of coolant in the expansion tank and the coolant actually spilling out of the top of the tank. Of course, in normal usage for the vast majority of boaters, the level of coolant drops slightly over time due to evaporation rather than it spilling over into the bilges.

In conclusion, I would recommend all boaters to change their OAT coolant at around 5 years as I do unless you have a serious problem with your coolant system which will be obvious and far more pressing.

Richard

 

[thinwater]

You don't have to agree. This is engine manufacture policy.

Obviously the source of risk is leaks. 25 ppm chloride is the condemning limit (ASTM D3306) for new coolants. That takes 8 grams of leakage in your system, which you could not notice (you have either math errors or misunderstood what I said). If you are sure you have no leaks, roll the dice. But have you ever tested for chloride? It these low levels it will not cause obvious corrosion. Rather, chloride is well known to cause microcracking of copper tubes.

Yanmar says annual (p33). This is a long-life coolant spec (p13). They give a higher condemning limit (<100 ppm for the water, which would be about 55-60 ppm for the resulting coolant).
https://www.yanmar.com/media/global...tionmanual/6HA2M-WHT_WDT_OPM_0A6HA-G00501.pdf

 

[RichardS]

You don't have to agree. This is engine manufacture policy.

Obviously the source of risk is leaks. 25 ppm chloride is the condemning limit (ASTM D3306) for new coolants. That takes 8 grams of leakage in your system, which you could not notice (you have either math errors or misunderstood what I said). If you are sure you have no leaks, roll the dice. But have you ever tested for chloride? It these low levels it will not cause obvious corrosion. Rather, chloride is well known to cause microcracking of copper tubes.

Yanmar says annual (p33). This is a long-life coolant spec (p13). They give a higher condemning limit (<100 ppm for the water, which would be about 55-60 ppm for the resulting coolant).
https://www.yanmar.com/media/global...tionmanual/6HA2M-WHT_WDT_OPM_0A6HA-G00501.pdf

Ah .... I see. When you stated the limit of "seawater (salt) contamination of 1 part per thousand" I assumed that you meant 1 ppt of salt in the coolant as that is normal scientific dilution notation. If you meant 1 part of seawater per thousand of coolant then my calculation was clearly a long way out!

Richard