Actually, I just didn't think this through. But it's nice to know there are some chemists out there. If the water was ultra pure, it would be pretty stable. What usually causes corrosion is dissolved oxygen.

But the main thought still holds...the problem is the amount of flushing, not whether the water is pure or tap.

Engineer here. This is indeed true. I'd like to add pure water is indeed less corrosive than water with impurities; however the effect is still measurable and it can actually attack nearly anything; especially at high temps and pressures. I like to think of it as having an abrasive force rather than an corrosive force, causing the water to retain impurities as a result of this. So using distilled water has no major advantage.

I have zero issues using Tap Water. But, if the Distilled Water is Mixed with Coolant it is no longer Distilled Water so it should not have the same properties as pure Distilled Water.

As a side note. I have a 1 Gallon Electric Water Distiller and have been drining moslty Distilled Water since the 1980s. So if I wanted to use Distilled Water to mix with the Coolant it would be even less of an expense for me then someone buying it Retail. I have no plans to use it in anything but the Car Battery if needed.

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84 300D, 82 Volvo 244Gl Diesel

hmmm. what's the electricity cost to run the distiller?

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Less then plugging in an Electric Car. Just kidding.

I don't know how to figure it out as I have never checked that Amperage while it is running so that I could calculate how the watts pre time period it uses.

I had one stop working and did not get another for over 3 Months one time and I did not notice any significant difference in My Electric Bill. Also My total Electric bill last Month was $58 and change.

There is also a convience Factor and not have do deal with finding as space for a bunch of Plastic Jugs or one big Bottle some place and there is no Fuel using trips to the Store just to buy Water.

Also My Wife and I put the Distilled Water in our own Bottles when we go some place so we usually don't by the typical Water Bottles that you see People on the Street Drinking From.

Between My Wife and I we drink 1-1.5 Gallons per day of the Distilled water. We Cook with Tap Water.

Back in the 1980s My Mother told Me there is somplace in France where People live a long time and they drink Distilled Water. But, that is not the main reason I switched. The City of Long Beach switched the Chemical they used to Purify the Water back then.
I don't like the Taste of the Tap Water and it give me a bit of gas to the extent I feel a little bloated;makes me burp.

When I drink Tap Water from the City My Mother used to live in it does not taste as bad and I don't have the bloating issue.

In short I think if you look at all of it I think the Cost evens out.

I bought the first Distiller from Sears (made in Japan) and it laste for something like 15 Years. The 2nd one I got from Sears was different and it only lasted a little more than 2 Years.

I had also bought My Mother the origanl one I got from Sears but She did not use it so I got it back and used that for about 10 Years till My Wife burned up the Cord. I repaird it but I bought an additona US made one.

I prefer the US made one as it works faster than the Japan Sears one.

I use Vinger to clean it but Citric Acid is what you are supposed to use.

The pic is not the exact one I have but looks almost the Same. The first one I got from Sears and the US made one look similar.

What burned out on the original one was the Temp Shutoff Sensor. When burned up it turns the Heater Element off permanently.

Attached Thumbnails

 

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84 300D, 82 Volvo 244Gl Diesel

I found a place that has the specs on the Water distiller.

750 Watts is also what I rememberd. One distiller takes 4 Hours to do 4 liters and the other takes less then 3.5.
With that you can determine the Watt Hours and I think your Electricity Bill may be in Kilowatts so you would need to convert Watt Hours into Kilowatts.
So if it runs 4 Hous that is a total of 3000 Watt Hours.

(Electric Space Heaters set on High are rated at 1500 Watts.)

Distiller specs
Power Input：: 110VAC 60Hz
Output Power : 750W
Volume : 4L
Distilled Water/per: 1L/H
Distilled Internal :All Stainless Steel
Over-temperature safety: power-off when temperature is 160 deg.C
Net weight : 4.5Kg
Package size:285*255*455mm
High Quality, Easy to operation
Produces water of the safest and cleanest condition

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84 300D, 82 Volvo 244Gl Diesel

The problem is the lack of FLOW in the flushing process.... due to the small exit venues usually available... hence my recommendation to take out the freeze plugs and use a directed nozzle on a flexible hose to get down to the bottom of the coolant cavity...and a vacuum inserted will help with muck too heavy to bring to the freeze plug holes .
If you have something like a concrete vibrator with a flexible enough end.... ideal for loosening that built up and concreted sediment.

If someone wants LOW Oxygen water... collect the house AC drip.... also a good reason NOT to use that to water plants... the opposite of hydroponics... which adds oxygen like an aquarium pump does for fish survival...

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

I agree. This engine has a serious flow problem.

In my experience keeping a stock W115 at operating temperature is impossible. Every one I've had will hit operating temperature (175) and sink down to about 160. If I open the heater valves it will momentarily drop to 125. I tried numerous new and used thermostats with the same results. Once the thermostat opens during warm up it immediately closes again as a surge of cooled water passes through. However it doesn't close as tightly and 160 degrees is where it ends up. This is all verified with a Fluke non contact thermometer. The gauge is dead on.

This drove me nuts on two cars and three engines until I finally did what the factory did with the W123 and converted to a three stage thermostat and housing. Now I hit 175 and hold it - just like my W123. In my current W115 the only way I can go over thermostatic is 75 mph fully loaded uphill in hot weather. Under those conditions I might hit approximately 195 for a short while but it comes back down immediately. In addition to all this I have a deliberately under driven water pump and a 5 speed which further slows the pump. Now I have good heat and less smoke.

I only mention all this because a hot running W115 is completely outside my experience. I suspect you have a serious blockage in the engine or radiator. A cool running engine in this chassis is the norm. I wish I had a magic solution for you but I think opening everything you can and manually removing sludge is your only course of action. If you have access to an IR thermometer you could check your gauge calibration and sweep the engine for hot spots. That could tell you where the problem is. If you're worried about heater core damage from further flushing just bypass it. Either way I would keep after it. The blocked parts of your engine are well above the average temperature of the coolant.

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1969 220D 5 Speed (OM616)
1983 240D 4 Speed
1985 300D Auto 376K
1985 300D Auto 275K

I have run 1 pound of citric acid in the cooling system heater fully on for 60 miles or 100km which maybe over several days and after a hose flush followed by 3 distilled water flushes I could not detect any further rust. This however were on 617 and 602 engines which both tended to get on the hot side but that treatment curred both engines. Perhaps your treatment using citric acid wasn't adequate just bringing it up to temp before flushing?

Are you catching the run off?

Redneck method would be to drain coolant, remove the thermostat, replace tstat housing, fill radiator through the disconnected upper radiator hose, Have another hose to direct water coming from engine, start cold engine and run it until the escaping water looked clean while continuously filling radiator with a hose. Drain, reinstall thermostat, add Zerex to 50% of system capacity, top up with water of your choice, drink a beer.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

Yes I catch the water that has antifreeze but after the third flush and for the final hose flush no I don't catch the rusty citric wash fluid.

I am going to offer a different comment. When I was a Kid and Teen in Californa People used only Water in their Coolent System unless they were going up to the Moutains; someplace where they expected it to get below Freezing.

They also did not do perodic Flushes on their Coolant Systems so scaly Rust would build up inside of those Coolant Systems.

If the Engine already is full of Scaly Rust flushing the Coolant System only loosens it and you can keep getting loose particles of rust for years afterwards.

It was not until the 1970s that using Coolant instead of only Water took hold.

So if your Block is rusted that Rust is going to continue to come out of it for a long long time.
With a Engine in that Condition it is OK to Pull the Radiator and have that tanked to clean it and OK to flush it with Water but you don't want to put anything in it that is going to loosen the rust.

If perodic flushes had been done that that might have prevented heavy Rust build up but if Water had been used as the only Coolant it is going to be rusty in the Block.

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84 300D, 82 Volvo 244Gl Diesel

you are never going to get this clean with the gravity drain method, what you need is to first remove the thermostat, and collect some bits and assortments from an auto parts store.

like a spare heater hose the prestone flush adapters that can accept a garden hose - remove a heater line and install your spare heater hose and cut it to install the adapter you bought, connect your hose to the hot side water line (washing machine line) and make sure hot water is flowing through. Open up the drains on the radiator and block

start the engine and flush it out till all you see coming out is clean water. You need a positive force behind the flush to get rid of this rusty water. Dont worry about the tiny amount of impurities in the tap water (unless you use well water) - if you are very strict on it you can blow air through the system to fully remove all water. Fill as you like.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

At radiator shops they have a hose connector with an air fitting to massively bubble feed the block...amazing what comes out with bubble activated water

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Thanks everyone for the new suggestions and replies. So a few followups/replies:

1) The temperature at low or moderate loads is super stable, as it is well controlled by the thermostat. I don't see the wide swings that were described above. Only at high load is the cooling system not able to keep up
2) The earliest 220Ds did not have oil coolers. So the cooling load on my engine is greater than on later engines. This suggests that MB identified a cooling deficiency and addressed it with oil cooling.
3) The W115 FSM says "when driving under load, in the mountains and bumper to bumper traffic...the coolant temperature readout may rise to the red mark (just below 250F) without any fault on the engine." They even bolded the statement "without any fault on the engine." So just because my engine gets very hot does not indicate it is out of the realm of normalcy for w115s.
4) The W115 FSM also provides recipes for coolant/water mixtures and one of the options is ~35% antifreeze. Although all of their mixtures include an additional "anticorrosion oil"... whatever that is.
5) I don't think my engine has the normal freeze plugs of other later engines. All of the ports on the sides of the engine have 17 mm allen fittings in them. None of them are simply plugs like I think you see in the om617.

I decided to roll the dice and do a second full treatment (degrease, citric acid, rinse, rinse, rinse...). This time, I am putting it all through the heater core as well (keeping my fingers crossed). I just started that today so it will be a few days before I know the outcome. As an aside, I do use a hose to push water fast through the heater core and block. As mentioned, the flow under gravity is too slow to carry much sediment. I will post again in a few days with another photo of the rinse water and see if any progress was made.

Thanks again!

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1968 220D, w115, /8, OM615, Automatic transmission.
My 1987 300TD wagon was sold and my 2003 W210 E320 wagon was totaled (sheds tear).