I'm changing the coolant on my 1986 K100RS. The manual specifies 2.8L in equalizing tank. What in the heck does manual mean with "in equalizing tank"? According to the instructions here, I should poor the 2.8L of mixed coolant (60% distilled water and 40% antifreeze) through the system cap until fluid just starts to come from the filler neck and flow to the overflow tank. I did that, however, the coolant never reached the filler neck. Do I need to poor more than 2.8L or should I just fill the overflow tank to 1/2 and start the engine?

bmwk100rs wrote:The manual specifies 2.8L in equalizing tank.

Which manual is that? Paste in a quote. Whenever you read something like 2.8l + 0.4l in equalizing (expansion, overflow) tank, it means 2.8l into the radiator + 0.4l into the expansion tank.

Attached are instructions from BMW's K75/K100 2V service manual downloadable from the Tech Page here. I have followed these as written. This system has worked in my Brick as intended during the nine years of my ownership. Filling the radiator slowly creates a chance for air in the system to escape as liquid enters. If air hasn't been bled from the system, or sufficient coolant hasn't been added, the fan will be running more often than usual.

Laitch wrote:Which manual is that? Paste in a quote. 

The Rider's Manual that came with the motorcycle.

Laitch wrote:Attached are instructions from BMW's K75/K100 2V service manual downloadable from the Tech Page here.

Thanks for the instructions.  However, I already poured the 2.8L and it has not reached the bottom edge of the overflow (arrow indicated in your instructions). Should I add more?

Cold or warm engine, filled or empty expansion tank? If I were doing this, my innate curiosity would top it up but keep track of how much I needed to add. You aren't filling the expansion tank through its hose coupling to the radiator, are you?

It's a straight forward procedure, plus it has hose-kneading! Who doesn't like to do that? Maybe recalibrate and start over.

Laitch wrote:Cold or warm engine, filled or empty expansion tank?

Cold engine and 0.4L in expansion tank. I have not installed the gas tank back yet. In addition, your instructions state that the system can be bled by just turning the engine with the starter. Therefore, it will not be warm.

Laitch wrote:You aren't filling the expansion tank through its hose coupling to the radiator, are you?

No, I am not. I'm poured the 0.4L directly into the expansion tank.

Laitch wrote:It's a straight forward procedure, plus it has hose-kneading!

Your instructions are straight forward indeed so I'll give it a try. Thanks!