As to the silica free coolant, I would think it hard to keep it that way in our cars!

The replacement coolant reservoirs are supposed to have a slow release silica additive in them, and the 126 block castings are supposed to have a silica content much higher than normal in aluminum alloys.

Like a good number have done, I just ended up settling on the Zerex G-05 coolant, especially since I can purchase it from local parts houses for roughly the same as anything else, and FAR less than buying direct from MB!

When I change (or have changed) the green coolant out in my 300SEL, should I just simply drain out the green until it stops, then refill with something like Zerex G-05, or is a flush necessary? I have heard from some that flushing on older cars could be a mistake because if you have a weak headgasket or heater core, it could cause problems, but I have no idea. My car does not have the original radiator if that makes a difference.

Thanks.

If nothing else, I'd at least flush it with water to push the majority of the green stuff out, if you're going to switch types.

The impression I had about flushing causing problems was that it was only a potential if you were using something fairly aggressive to flush with.
That being said, I'd be tempted to consider it if I had a car that was running warmer than I thought normal, and I'd already eliminated the less aggravating possibilities.

Thanks. No, the car does not run warm. It stays around 80°C on the gauge. I just wanted the green junk out of there.

I went to buy some Zerex antifreeze only to find out there are several kinds and all are different colors. I opted for the G-05 a gold color liquid recommed for my year of Mercedes. For those of you who want the technical information on the different types of antifreeze here is a link.

http://gates.com/downloads/download_common.cfm?file=MOTORCoolantFeature.pdf&folder=brochure