Intestinalworm · Dec 30, 2022

2003 Discovery 2 Td5

I have a new carbon brushbox for my alternator that I want to install. I also want to fully drain my coolant, flush, and then fill with new OAT coolant and distilled water: OAT concentrate to DW = 50:50.

Now I understand there is a threaded plug behind the alternator so that you can drain coolant out of the engine at the lowest point?
Is it correct then that if I remove this threaded plug then I can drain out all the coolant in the engine - c.13L???

If instead I only drain coolant via the 13mm drain plug under the radiator (have to remove the two underbody plastic shields first) then only 8L of coolant will drain out (you don't drain out coolant in the lower part of the engine block - a further 5L)?

If I do remove the threaded plug behind the alternator, does it have a replaceable washer or do I use blue thread sealer when putting it back in?

Am I missing anything here?

Thanks for any help on this one.

Intestinalworm · Dec 30, 2022

Well, just took the two original black plastic underbody shields off (one in front of the damper and the other just behind it) - both of the plastic shields held on with 5 x 8mm hex screws with large washers - screw into yellow "grommets" fitted into the sheet metal (I somehow had two screws/washers missing and two yellow "grommets" missing!). Was able to maneuver the shields out by hand with a bit of bending around the various obstacles. Should be okay to reinstall the shields later - does anyone know where to get the screws/washers/yellow "grommets" - my OCD is getting to me!

While the shields are off (never off before unless a mechanic removed them at some point in the past - and never replaced the correct screws!) I might check out the transmission fluid lines that go to the radiator!

I remember somewhere it said you needed to jack up the body to get the plastic shields out.

Anyway, I also have access to the cooling system drain plug now as well.

Beneagles · Dec 30, 2022

^ in the UK they are available from motor factors, motoring retailers such as Halfords, main Dealerships....and of course ebay.

No idea about Oz

NPG · Dec 30, 2022

Intestinalworm said:
2003 Discovery 2 Td5

I have a new carbon brushbox for my alternator that I want to install. I also want to fully drain my coolant, flush, and then fill with new OAT coolant and distilled water: OAT concentrate to DW = 50:50.

Not familiar with the quality of Australia's tap water but distilled water is generally not a good idea for cooling systems. Soft water is your best option here.

Stanleysteamer · Dec 30, 2022

NPG said:
Not familiar with the quality of Australia's tap water but distilled water is generally not a good idea for cooling systems. Soft water is your best option here.

Could you enlarge upon this please?
I have very soft, and slightly acidic water in France and hard water in the UK.
My (very) basic common sense tells me that it wouldn't be a good idea to put acidic water in my engine but nor would it to put hard, i.e. calcium ridden and alkaline water in it either, so if I cared I'd put de-ionised water in so that it don't attack any of the metals involved.
As it's a closed system I expect that neither would do very much harm before they ran out of either acidity or alkilinity or calcium to block stuff up and do damage, especially as antifreeze comes with inhibitors in.
Hence my request.

Intestinalworm · Dec 30, 2022

NPG said:
Not familiar with the quality of Australia's tap water but distilled water is generally not a good idea for cooling systems. Soft water is your best option here.

Melbourne (Victoria, Australia) takes its tap water from controlled-catchment areas; the water is soft and is regarded among the best in the world. Notwithstanding that, I will dilute the OAT 50:50 with distilled water, not a huge deal really, but given that distilled water is cheap to buy I thought it best to do it properly.

Intestinalworm · Dec 31, 2022

Beneagles said:
^ in the UK they are available from motor factors, motoring retailers such as Halfords, main Dealerships....and of course ebay.

No idea about Oz

Does anyone have a part number for the original 8mm metal hex screws /washers/yellow 'grommets'?

I noticed that one screw that was missing was replaced with (but plain at the top - no Phillips screw indent as shown in the one below):

Intestinalworm · Dec 31, 2022

If instead I only drain coolant via the 13mm drain plug underneath the radiator (the two underbody plastic shields are now removed) then only 8L of coolant will drain out? If I remove the threaded plug behind the alternator however, then all the coolant drains out - all 13L of coolant? Is that correct?

NPG · Dec 31, 2022

Stanleysteamer said:
Could you enlarge upon this please?

Sure Stan

Besides the lack of minerals and other impurities, what makes distilled and de-ionised water different from tap water is the low concentration of ions, precisely because distilled and DI water is purified. It is worth noting that these ions come from dissolved salts and inorganic materials, also known as electrolytes.

The lack of ions tends to make the water react more easily with carbon dioxide present in the air, producing carbonic acid and thus changing the pH from 7 (neutral) to somewhere close to 5 (i.e. about 100 times more acidic than pure water). Carbonic acid is known to accelerate the corrosion rate of mild steal by enhancing the cathodic reaction. For instance, it is well known that DI water has severe corrosive effects on materials such as carbon steel, copper and cast iron while it is perfectly safe to use with aluminium or stainless steel.

Note also that a good quality OAT at 50% concentration as recommended by LR provides adequate protection against corrosion, scaling, etc. when mixed with tap water. You can always monitor the pH of coolant by using pH test strips. Ideal values should be between 7 & 9.

Intestinalworm · Dec 31, 2022

NPG said:
Sure Stan

Besides the lack of minerals and other impurities, what makes distilled and de-ionised water different from tap water is the low concentration of ions, precisely because distilled and DI water is purified. It is worth noting that these ions come from dissolved salts and inorganic materials, also known as electrolytes.

The lack of ions tends to make the water react more easily with carbon dioxide present in the air, producing carbonic acid and thus changing the pH from 7 (neutral) to somewhere close to 5 (i.e. about 100 times more acidic than pure water). Carbonic acid is known to accelerate the corrosion rate of mild steal by enhancing the cathodic reaction. For instance, it is well known that DI water has severe corrosive effects on materials such as carbon steel, copper and cast iron while it is perfectly safe to use with aluminium or stainless steel.

Note also that a good quality OAT at 50% concentration as recommended by LR provides adequate protection against corrosion, scaling, etc. when mixed with tap water. You can always monitor the pH of coolant by using pH test strips. Ideal values should be between 7 & 9.

Yes, hardness and pH linked - very soft water can undergo a rapid pH change (to acidic or alkaline); hard water on the other hand is buffered (with carbonates?) and will maintain a stable pH unless a sizeable amount of acid or alkali is added (simplified explanation). Incidentally, I do know that some pharmaceutical plants have suffered very expensive corrosion in their water-for-injection plants; the almost 100% pure water seems to leach-out ions from the stainless steel!?

Might have to re-visit my corrosion textbooks! DI water is good in a lead-acid battery (stop potential electrode fouling), but maybe not needed (not a good idea?) in the coolant system - especially given that tap water here is good quality.

Intestinalworm · Dec 31, 2022

Stanleysteamer said:
Could you enlarge upon this please?
I have very soft, and slightly acidic water in France and hard water in the UK.
My (very) basic common sense tells me that it wouldn't be a good idea to put acidic water in my engine but nor would it to put hard, i.e. calcium ridden and alkaline water in it either, so if I cared I'd put de-ionised water in so that it don't attack any of the metals involved.
As it's a closed system I expect that neither would do very much harm before they ran out of either acidity or alkilinity or calcium to block stuff up and do damage, especially as antifreeze comes with inhibitors in.
Hence my request.

Just an aside, but the Haynes manual (hardcover paper) you recommended some time ago is just great!!! Got a second-hand copy in fantastic condition, but the pages are browning a bit. So many books turn to dust due to crumbling nitrate-treated paper - wonder if they have a cheap way of arresting this yet?

NPG · Dec 31, 2022

Intestinalworm said:
Yes, hardness and pH linked - very soft water can undergo a rapid pH change (to acidic or alkaline) relatively quickly

100% - it takes about 2 hours for distilled water to absorb all the carbon dioxide it can from the atmosphere and achieve its final pH.

Intestinalworm said:
Incidentally, I do know that some pharmaceutical plants have suffered very expensive corrosion in their water-for-injection plants; the almost 100% pure water seems to leach-out ions from the stainless steel!?

Corrosion or metal leaching are not uncommon especially with water of high purity. With stainless steel, this is very low but if not acceptable, synthetic polymers such as Teflon would be the option.

Intestinalworm said:
Might have to re-visit my corrosion textbooks! DI water is good in a lead-acid battery (stop potential electrode fouling), but maybe not needed (not a good idea) in the coolant system - especially given that tap water here is good quality.

Why use distilled when you have that kind of water running through your tap

Stanleysteamer · Dec 31, 2022

wow!
thanks for all that!!
so best to shove the hard water in from our domestic supply in the UK then!
Ta mates!!!

Intestinalworm

Well-Known Member

Intestinalworm

Well-Known Member

Beneagles

Well-Known Member

NPG

Well-Known Member

Stanleysteamer

Well-Known Member

Intestinalworm

Well-Known Member

Intestinalworm

Well-Known Member

Intestinalworm

Well-Known Member

NPG

Well-Known Member

Intestinalworm

Well-Known Member

Intestinalworm

Well-Known Member

NPG

Well-Known Member

Stanleysteamer

Well-Known Member

Similar threads