pull your transmission dipstick...
what color is the fluid in there? pink or frothy... drain your transmission and replace your radiator asap!
I've heard that several types of block sealers will leave a reddish residue in the coolant. how long have you had the car?
what color is the antifreeze in your car?

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!