Ahhh, the ever-steady flow of misinformation.
Mercedes recommends a de-oil flush to remove oil deposits from a failed head gasket, tranny cooler, or similar problem. Some dealers use Cascade, perhaps Shout, or similar non-foaming, relatively safe degreaser. MB sells a specific de-oil product (part # 001-986-21-71) for this purpose, it's about $10 wholesale. It has a 6 month shelf life, so only buy this if you plan to use it right away. The bottle will come with a date code on it. This is to be done ONLY if necessary, and before the acid flush (read on).
MB then recommends a citric acid flush for diesel engines only, and ONLY if corrosion deposits are found in the cooling system. They do NOT specify this acid flush for any gas engine that I know of. It's a 10% mixture, IIRC, or 1.0kg per 10 liters of system capacity. MB sells the acid powder but it's expensive. You can buy the powder generically and
AFAIK, there's no shelf life limit. The generic cost is MUCH less. I saved some links to internet retailers if anyone is interested, I can dig it up.
The procedure for the acid flush is here:
http://www.meimann.com/docs/mercedes/Citric_acid_flush.pdf
And in this document, note that high temps for the 60x are to be remedied by an acid flush with the OLD radiator in place (so loosened deposits won't plug up a new one), then after the flush is complete the radiator is to be replaced:
http://www.meimann.com/docs/mercedes/OM603_radiator_notes.pdf
Prestone & similar flushes are probably safe and OK for minor cleaning, but the MB acid flush is more thorough. If you have no current cooling problems, I'd just use the Prestone type stuff. The MB acid procedure is heavy-duty and used to remedy an actual *problem*, it's not to be used as a preventive maintenance between anti-freeze changes. If you use the acid, observe the EXACT factory procedure and don't screw around with this stuff. Keep it off concrete too.
You'll need the forced-open t-stat, which you can "make" for the 61x engines from an old 'stat, but may not be possible with the 60x. YMMV, etc...
Oh - and use ONLY the MB dealer anti-freeze, or Zerex G-05 (the amber stuff). NEVER EVER EVER use the green or orange junk in any MB with plastic radiator tanks or aluminum parts in the cooling system (head, radiator, etc). That basically means all MB's from about 1980 and newer. It's only $10/gal once every 3 years, so you have no excuse about it being "expensive"...!
