I bought a 1998 C230 almost two years ago and I'm changing the coolant. It has the same color coolant in it as my 1991 190E I've had for many coolant changes. I just looked at the new coolant I got and I noticed it's blue. I googled it and got some information, but I was wondering if anybody here knows anything about it.

One specific question I have is how compatible are they with each other. How careful do I have to be flushing the old stuff.

__________________
5 speed '91 190E 2.6 320,000 mi. (new car, fast, smooth as silk six, couldn't find any more Peugeots)
5 speed '85 Peugeot 505 2.5l Turbo Diesel 266,000 mi. (old car, fast for a diesel, had 2 others)
5 speed '01 Jetta V6 (new wifes car, pretty quick)
5 speed '85 Peugeot 505 2.2l Turbo Gas 197,000 mi. (wifes car, faster, sadly gone just short of 200k )
5 speed '83 Yamaha 750 Maxim 14,000 mi. (fastest)
0 speed 4' x 8' 1800 lb Harbor Freight utility trailer (only as fast as what's pulling it)