My owners manuals specifically mention Zerex G0-5.

 

Is that $18.80 per gallon? Or 3 gallon? There is nothing to click on for more info on that site.

 

Per gallon. Slightly cheaper here:

Home Page > Search > Q1030004 > ES#2522045 Anti-Freeze / Coolant - Priced Each - Q1030004

They also sell the M/B Citric Acid cleaner for the complete system flush. This is the same cleaner that is used in the service department of the Mercedes-Benz dealership when a cooling system flush is being performed:

http://www.ecstuning.com/Search/Citric_Acid/ES1609953/

From section 20 of the M/B service manual....This has been referred to as the "Gold Standard" of radiator care!
20-015 tells you to:

Drain the cooling system of all the old coolant
Remove the thermostat and replace it with a "forcibly-opened" thermostat p/n 000 589 63 00
Connect a flushing connection pipe (a tee) p/n 117 589 00 90 00 between the upper radiator hose and the radiator
Connect a tap water hose to the tool fitting
Open the surge tank cap
Set the heater to defrost on cars with automatic CC so the aux coolant pump runs
Start the engine and run it at 2500 RPM
Open all drain plugs and turn on the tap water to maintain a full cooling system at all times while the engine is runniing
Flush for 5 minutes to remove all old coolant
Shut off engine, shut off tap water, and allow cooling system to fully drain
Install radiator and crankcase drain plugs
Dissolve citric acid powder in 5 liters of water
Fill cooling system with solution and top off with water, bleeding as necessary
Install surge tank cap and start engine
Run engine for 15 minutes at approximately 2500 RPM and blip throttle occasionally
Make certain that coolant is flowing through radiator and heater core.
Open cooling system drains again and turn on tap water to flush cleaning solution from cooling system
Start engine and run at 2500 RPM for 5 minutes to flush all cleaning solution from system
Shut off engine and remove special tool from upper radiator fitting
Reinstall normal thermostat
Make sure that all drain plugs are installed and tight
Remove the surge tank, flush it separately, and reinstall it

The conversion then is 1.1 lbs of citric acid to 1.3 gallons of water to mix it up initially... then you are adding water on top of that (not distilled water as this is just a flush). So it's really 1.1 lbs per the entire cooling capacity of the engine which is roughly 9.5 quarts (around 2.4 gallons).

In summation...

flush old cooling system with garden house and kit for 5 minutes to get all residue out

mix 1.1 lbs citric acid powder to 1.3 gallons of water and add to engine, adding water on top of that until cooling system is full

Run for 15 minutes at 2500 RPM

drain

flush with engine running at 2500 with hose running and attached with drains wide open

Seal everything up and refill with coolant and distilled water

Another view...

www.w124performance.com/docs/mb/OM60X/citric_acid_flush.pdf

 

I see that NAPA sells both the 50/50 and full strength...any preference?

 

No preference, but with the two prices you could figure out how much you are paying for the half a jug of distilled water, I'll bet you'll be surprised.

 

I think I am just going to drain and flush with engine running so T-stat opens up, etc. I noticed that the pics show changing out the t-stat and gasket. I don't think I will do that unless some really good reason. Car does not get hot, t-stat works fine, no leaks. I assume this is changed more for inspection than for anything else. I am going to buy Zerex GO-5, HOW MUCH SHOULD I buy? I think I will buy the 50-50 premixed, does it take 3 gals?

 

Coolant system takes just under 12 quarts, so you're good with 3 gals of mix.

 

I was watching a Motorweek episode....garage guy said even on all aluminum engines with plastic parts in cooling system......need to change fluid......fluid can become acidic & eat plastic parts.

 

It can also eat aluminum much easier.

 

That is provided you have the complete system empty and nothing left in the block. If any water is left in the block, then you will have less than 50/50.

 

I had my system flushed AND had the -10C mod done to the fan at Buckhead Imports. The charge for the fan mod was $50, so he quoted me $240 or $250.

When I got there, after the work was done, he said, "Ummm, this didn't take as long as we thought, how's $190 sound?"

I guess $160 at a dealer is not all that bad.

 

That's about what they quoted me as well. I'd rather have them do it for that price.

 

Takes 20 minutes, you guys are nuts!

 

Since you didn't go into detail.. You realize getting the engine hot to open the thermostat and then inducing cold water is not a good combination.. not to mention the thermostat will then close with the cooler temp from the water. So unless you intend to hook up to the home hot water tank..

 

The total capacity of the cooling system is 3 gal but you will only be adding 2 gallons to your reservoir because if you didn't drain your engine block (most don't) after flushing then you already have approximately 1 gal of whatever water you used during the flush to start with in the cooling system. Therefore, you shouldn't add 50/50 premix because it will be further diluted (to 33/67) by the water in the engine block.

Just get 2 gallons of the full strength G-05 and add 1.5 gal of it to the reservoir and then top off with 0.5 gal distilled water.

 

Keep in mind that when you start your car on a cold day only the coolant inside your engine is warmed. Once the coolant warms up to the point where the thermostat begins to open it is replaced with more cold coolant from your radiator. Therefore, the running engine has to be able to tolerate water well below 0 deg F even after it has been running long enough to open the thermostat. So cool tap water will not cause any issues during a coolant change. As an example, many motor boats are powered by automotive engines (with only minor modifications) and are cooled by raw water.

 

Using cold water on an engine warmed to operating temperature is not a problem. You never want to add any water, hot or cold, to an engine that is overheated. It must cool down first before adding water.