My local dealer's counter man never heard of it. Does anyone know the MC part number? Other sources?

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1991 350 SDL
183,000 miles

1982 240D
130,000 miles

Chris:

You can buy citric acid in many of the health-oriented food stores that feature organically grown foods, etc. One such place in my area has it in a drum that you scoop it out of for $7.95lb.

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Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

where do you use this?

benzat
1982 380 SEC

Chris,
The MB part no. for the citric acid is 00-989-10-25. That's for 0.5kg(500g) or 1.1 lb. Cost $17.
If you are going to flush your cooling system, you really need to use a degreaser first. The acid will not have any effect if grease/oily deposits are in the system. The degreaser is part no.001-986-21-71 for 500g or 1.1 lb.Cost $11. You can find the citric acid in your Super Market. Look in the home canning section. For the degreaser you can use a non-foaming automatic dishwasher compound. Do not use strong alkaline cleaners on light alloy(aluminium) radiators.
Bill Lewallen Lexington,Ky. The Bluegrass State, but the grass is really green, and we use the GREEN coolant.

First, Bill is right about using the Mercedes degreaser first, but he left out a "0" at the beginning of the part number for the "Lemon Acid" as Mercedes calls it.

I also seriously doubt that using a supermarket citric acid would be the same as using the Mercedes product. First, the supermarket/health food store product is designed for human consumption. The Mercedes product is not. For instance, the Mercedes Lemon Acid clearly states on the label that you shouldn't allow any to get on your skin. As for putting "a non-foaming automatic dishwasher compound" in my car's cooling system, I simply wouldn't do it. It simply wasn't designed to do that specific job.

Finally, a local dealer just told me that you should thoroughly flush the system with water after running the Lemon Acid through it, and remove the thermostat to be sure it's rinsed thoroughly as well.

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Scott Longston
Northern California Wine Country...
"Turbos whistle, grapes wine..."

Chris, Mike and Scott,
Sorry I gave the wrong no. for the decalcifacation, derusting compound. It's 000 989 10 25. You can use tartaric or oxalic acid. However, the Mercedes Factory Manual prefers citric acid. The citric acid sold in our markets in Ky. is pure citric acid powder. The citric acid sold by Mercedes is made in Indonesia, and the label says nothing about getting any on your skin. It does say if in case of eye contact to flush thourghly with water. Also, the label states to keep out of reach of children. The last MB cooling system I flushed, I had the citric acid all over my hands from removing the drain plug. No harm to my hands, but they had a nice lemon smell. A 10% solution of citric acid is a fairly weak organic acid.
As for the final flush; if you refer to the instructions in the MB manual, it says to flush at least three times with fresh water while running the engine for at least 5 min. with each flush.
If your radiator is all brass(no plastic)you can use a stronger alkaline cleaner for degreasing. You can get TSP(tri-sodium phosphate)from you hardware store.
Bill Lewallen Lexington,Ky. Headquarters of Valvolene, Division of Ashland-Marathon Oil- Maker of Mercedes antifreeze Glysantin G05.

Honestly, Bill, the bottle I have says (along with all of the other stuff) to not get it on your skin. And the local dealer told me to remove and rinse the thermostat thoroughly by hand. Go figure...

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Scott Longston
Northern California Wine Country...
"Turbos whistle, grapes wine..."

Scott,
We must have different containers of citric acid. The one I have is the MB blue color with the MB star and some German and maybe French writing and of course English. The only English is inside a box in the middle of the label and it states:"In case of eye contact flush thoroughly with water. Do not take internally. KEEP OUT OF REACH OF CHILDREN!"
About removing the thermostat after the citric acid flush and rinsing thoroughly with clear water; The instructions in the Factory Manual clearly states to remove the thermostat before starting the cleaning process. Therefore the thermostat should not be installed during the flushing procedure. If you had ever flushed a Mercedes cooling system using the method in the Factory manual, you should have remembered this. Another thing you might recall is that the concetrated lemon juice used in the acid flush will not harm your hands.
Bill Lewallen Lexington,Ky. Home of LexMark Printers