My wife was driving the 300e last week when I was out of town. The low coolant light came on. She had the smarts to add antifreeze, but she did not know there was any difference between the MB coolant and Prestone.

She added about 1" of Prestone to the reservoir.

Will this mess up the the coolant? Should I drain it and replace with MB coolant, or not worry about it?

Bill

The bigger issue would be to look into what caused the coolant tank to become low. There is really no reason for it to leak out. Make you have a hose with a pinhole in it, or the hose clamps need tightening. For now Id find out why, then I'd think about flushing the cooling system while your at it with MB coolant. The thing is Mercedes coolant is made for mercedes and it has a low acidity. Acidic coolant ruins engines.

__________________
Current Stable:
1994 S500 v140, 210k miles, white with grey.

Former Mercedes in the Stable:
1983 300CD Turbo diesel 515k mi sold (rumor has it, that it has 750k miles on it now)
1984 300CD Turbo Diesel 150 k mi sold
1982 300D Turbo Diesel 225 sold
1987 300D Turbo Diesel 255k mi sold
1988 300 CE AMG Hammer 15k mi sold
1986 "300E" Amg Hammer 88k mi sold (it was really a 200, not even an E (124.020)
1992 500E 156k mi sold
etc.

1 inch of coolant in the reservoir hardly seems enough to trigger the coolant light. the sensor in the reservoir is known to be quirky. mine acted up this summer and i merly cleaned it and greased it with silicone grease. i don't think it's urgent to flush and refill your coolant but as omegabenz says i would look into why it was low in the first place.

__________________
joE
1993 300e-2.8 - gone now <sigh>
"Do not adjust your mind, it's reality that's malfunctioning"
http://banners.wunderground.com/bann...L/Key_West.gif