W210 Coolant Flush Proceedure?
 

Surprisingly little information using "search function" on this topic.

Anyway, I just got my W210 wagon back from the body shop after the Wife's little collision?:eek: The radiator was cracked and replaced and despite my specific request, they used the green stuff to refill the cooling system. My current mix is probably 50%water, 25% Merc brand fluid and 25% green stuff fluid.

How can I flush out the green coolant and replace with the Merc brand yellowish color coolant?

Was planning on pulling lower radiator hose for most of the system but I am clueless regarding engine block and heater core drains.

Outline of process and helpful tips would be very much appreciated.

Aloha

You don't mention which year and model. I have a '99 E430 with the M113 V-8. The radiator has a drain valve on the lower left corner of the radiator. After I drained the radiator I opened the block drain, which is on the right side of the block above the motor mount, but only a few drops came out. Apparently M-B has designed the system to drain the block along with the radiator. I measured the quantity drained and it was very close to the capacity listed in the Owners Booklet.

Thanks Vince....It's a '98 E320 *
 

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Coolant flush on '97 E300
 

I'd like to perform a cooling system flush on my diesel 606 before the winter. I don't knwo the last time it was done on this car if ever. I remember reading in a previous thread about a citric acid you can buy from Mercedes parts and mixed with water to clean out the cooling system.

Procedure of coolant flush:

1. Lower left radiator drain valve
2. Do I need to drain out of the block? If so where?
3. Run the citric/water mixture for about 30 minutes or so in idle
4. Flush and replenish with MB coolant mixture.

Am I on the right track? If so I'd like to buy the supplies so I can do this on my day off this week possibly....

I don't know about anything about the citiric acid product and am not familiar with the diesels. However, I would be surprised if there were sufficient "crud" in the system to warrant a flush. A coolant change ensures that the corrosion inhibitors in the coolant are fully capable of doing their job. That is the primary reason for changing the coolant.

Personally I would take the car back to the body shop, explain that they screwed up, and have it done properly.

I took a look down on the left side of the radiator and saw only a small "nipple" if you will sticking out of the radiator. It seems as though disconnecting the lower radiator hose would more quickly drain the system.

As far as refilling the cooling system, does all the new fluid get entered into the sytem through the expansion tank next to the airbox?

Thanx In Advance guys!

Pulling the lower hose will spill coolant all over the place. I prefer to place a hose on the nipple at the drain valve and run the hose to a bucket. It only takes 3-5 minutes to drain (make sure the radiator cap is off). When I did my E430 I didn't spill a drop. The system fills through the expansion tank.

Thanx Vince.... How is the nipple opened to relieve the collant?

Hi michakaveli,

I don't know your car so I can't help with the specifics, but on an 1987 420 SEL with around 14 quarts of coolant you need 3 boxes of the citric acid that MB sells for about $16 per box or .5 kg.
The dealer needed to order it so don't expect him to have it. I would try to find it at a drugstore or chemical supply store (citric acid or lemon acid).
You need to have the mixture circulate in the car for 15 minutes at about 2,500 rpms.
Then flush and fill with proper antifreeze mix. I needed a little more than 1 gallon for the minimum mix.
I used hot water to mix the stuff and filled it through the expansion tank.
I don't know where to drain your block.
You might want to get a new cap if yours is old and might not hold full pressure anymore. I learned that my still original cap had been "upgraded" by MB to hold a higher pressure, which helps with running it cooler.

Good luck

Reinhard Kreutzer

On my E430 (and most of the plastic tank M-B radiators) there is a red plastic "cap" for the drain valve. It has a screwdriver slot in it. Just slip a length of hose on the nipple, open the radiator cap, and open the drain valve. It is accessible from underneath after pulling off the forward section of the plastic undertray. To remove the undertray, drop the rear section (4 bolts) and then drop the front section (8 bolts - three in each wheel well and 2 at the front). It really is qiute easy.