Build up in new (10k miles) Water pump - what causes this?

[Jeff K]

New cooling system, all parts less then 10K. (radiator, hoses , water pump etc.)

25797

What is this build up (looks like calcification) in the water pump. Can it be avoided?

I used proper coolant and distilled water.

Thanks
Jeff

[Jonathan]

Hey Jeff,

If the calcium/hardness you are seeing there didn't come in new with the replacement coolant, it might already have been in there. One thing found in boilers or other water systems is that if they are scaled up from previous poor water chemistry, once you add in a better quality, or pure water to the system, it will have the effect of slowly dissolving the scale on the inside of the pipes back into solution. What might then happen is it can scale out on a surface that is hotter than others or where the flow characteristics changes and lets it slow down.

Either that or what you had thought was distilled water might have had some hardness in it (or the concentrated coolant itself). Keep in mind that if you bring impurities in to the system they either need to be removed or they will build up and concentrate. If a liquid flashes off as steam it will generally be mostly the pure water portion and very little of the minerals. This won't always be the case as the force of it flashing out can mechanically carry out the minerals with the flashing water. So if you had overheating problems at some point and the system flashed off coolant which was replaced with new coolant, you might have been concentrating up the dissolved solids without realizing it.

[Jeff K]

Hey Jeff,

If the calcium/hardness you are seeing there didn't come in new with the replacement coolant, it might already have been in there. One thing found in boilers or other water systems is that if they are scaled up from previous poor water chemistry, once you add in a better quality, or pure water to the system, it will have the effect of slowly dissolving the scale on the inside of the pipes back into solution. What might then happen is it can scale out on a surface that is hotter than others or where the flow characteristics changes and lets it slow down.

Either that or what you had thought was distilled water might have had some hardness in it (or the concentrated coolant itself). Keep in mind that if you bring impurities in to the system they either need to be removed or they will build up and concentrate. If a liquid flashes off as steam it will generally be mostly the pure water portion and very little of the minerals. This won't always be the case as the force of it flashing out can mechanically carry out the minerals with the flashing water. So if you had overheating problems at some point and the system flashed off coolant which was replaced with new coolant, you might have been concentrating up the dissolved solids without realizing it.

Ok, thanks Johnathon. I'll clean it out and start with all new coolant.

[hmcelraft]

Be careful where you buy the new antifreeze. I would recommend a premixed 50-50 extended-life like Prestone.

[kings1527]

Be careful where you buy the new antifreeze. I would recommend a premixed 50-50 extended-life like Prestone.

That's exactly what I've used since I've become an owner and I've had great results with it. So easy to work with. Just dump it in and drive and haven't had any calcification issues after about 6k miles.

[David T]

That's exactly what I've used since I've become an owner and I've had great results with it. So easy to work with. Just dump it in and drive and haven't had any calcification issues after about 6k miles.

You should use soft water not distilled. If the water in your area is hard then use the pre-mixed 50/50 anti-freeze.

[Jonathan]

You should use soft water not distilled.

May I ask you David what the reasoning is behind that?

[hmcelraft]

After looking at the picture again it reminds me of the way a system appears that is fully exposed or had very little corrosive protection in it. Some people have made the mistake of mixing water with a 50-50 premix which can really lower the protection.

[David T]

After looking at the picture again it reminds me of the way a system appears that is fully exposed or had very little corrosive protection in it. Some people have made the mistake of mixing water with a 50-50 premix which can really lower the protection.

Distilled water is "hungry" for ions. It tends to want to dissolve metals to satisfy that. Soft water already has some minerals in it so it is more balanced. Too many minerals (hard water) and they also will come out and deposit themselves. Deionized water is OK too but ordinary soft tap water is fine. Anti-freeze does a few things. First of all at a 50/50 concentration it provides maximum freeze protection and boil protection (it lowers the freezing point of the coolant and raises the boiling point). It has lubricants for the seal in the water pump. It has buffering agents to maintain proper Ph (important to prevent electrolysis). It contains anti-foaming compounds to reduce aeration. These properties are all optimized for the 50/50 concentration. If you don't maintain that concentration or over a long time this "package" of additives gets used up. You should test the coolant every year for concentration and Ph and every 5 years change it.

[Mark D]

You should use soft water not distilled. If the water in your area is hard then use the pre-mixed 50/50 anti-freeze.


Distilled water is "hungry" for ions. It tends to want to dissolve metals to satisfy that. Soft water already has some minerals in it so it is more balanced. Too many minerals (hard water) and they also will come out and deposit themselves. Deionized water is OK too but ordinary soft tap water is fine. Anti-freeze does a few things. First of all at a 50/50 concentration it provides maximum freeze protection and boil protection (it lowers the freezing point of the coolant and raises the boiling point). It has lubricants for the seal in the water pump. It has buffering agents to maintain proper Ph (important to prevent electrolysis). It contains anti-foaming compounds to reduce aeration. These properties are all optimized for the 50/50 concentration. If you don't maintain that concentration or over a long time this "package" of additives gets used up. You should test the coolant every year for concentration and Ph and every 5 years change it.

There is nothing wrong with using distilled water to dilute engine coolant to a 50/50 ratio. Distilled water is not "hungry" for ions after being mixed with engine coolant. The ion related corrosion issue you described would only apply if using pure distilled water.

When you buy 50/50 premix coolant from the store it has been pre-diluted with distilled water to achive the correct ratio. When buying full strength coolant OEMs and coolant manufacturers recommend diluting using distilled water.