1985 K100RS coolant capacity clarification.

mcmlcccvrs said:

The owners manual states 2.8 liters (3 quarts) with 0.4 liters in the equalizing tank. Clymer states 3.0 liters (3.2 quarts) and 0.4 liters in equalizing tank. The quarts are U.S. volumes. How much are you guys putting in these bikes?

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PGlaves said:

On my K75s I assume I will need at least three quarts. Then I add coolant and as I do so massage the hoses until I am confident the air is out. When the collant is up to the cap I then add to the midpoint in the expansion tank. It takes a bit less than 3 quarts but the block is smaller on a K75 than on a K100.

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mcmlcccvrs said:

Got it! Not so much a definitive measured amount necessarily.

Thank you.

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98lee said:

Correct. Completely full at the radiator cap with no trapped air in the block (run the engine until the thermostat opens. Usually 7-10 minutes or until the fan kicks on). Then let it cool down and top off. Then fill overflow bottle midway between hot and cold.

Before filling radiator, make SURE that there are NO cracks in the hose between the radiator fill neck and the overflow bottle. A crack in this hose will cause air to be sucked into the radiator and will cause overheating.

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