K11 Owners Group

[Grunter]

Following my problems with the bike overheating when I was away in Switzerland last month, the coolant which was relatively new, (only 2 months old) changed from the light pink colour to that of milk chocolate.

There is no leak anywhere in the system proved by the level exactly as it was before I left UK. I am going to drain the system, remove the thermostat and reverse flush it out with water using a hose.

Up to that point - no problem. However, every time I drain the system I always spend hours trying to eliminate air from the cooling system, a problem that never happens with my K75s motor which is basically the same but smaller. Is there an easy fix to clear any air locks?

On another, but connected point, the owners handbook states any new coolant concentrate must be free from 'Nitrites' whatever they are! So what are they?
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1997 K1100LT
1994 R1100RS

[Scott_Anderson]

If your coolant is turning milk chocolate, it sounds like you may have a seal issue with the oil pump.
The K bikes have 1 pump what pumps both water and oil. The pump shares 1 common shaft, 2 mechanical seals between the water chamber and the oil chamber with an air gap between the seals. This air gap is supposed to be open to drain out the bottom of the front of the engine. Sometimes this drain port gets plugged up with road grime/crap. If this passageway is plugged up firm enough and you have a leak at your oil seal, the oil pressure is greater than the water pressure and will push the oil into the water side of the pump and thus contaminate your water system.
Not saying this is your problem, but it is worth making sure the drain passageway is clear and open.

When you change your fluid make sure you give it a good flush...
When refilling, mix the coolant at least 50/50 with DISTILLED water, not tap or well water.

The nitrates issue is something that causes a negative reaction with aluminum. Since there are a lot of new automotive engines with aluminum in them now most automotive coolants are nitrate free.

When you say your coolant is pink, I'm guessing that you are not using the BMW branded coolant as it is blue.
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Ride safe.



1995 K1100LT 0302044
1997 R1100RT ZC62149
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)

[Al.]

Was it leaking at the cap.
I had overheating and got new cap.
Problem solved.

But it was leaking out at cap.

But Scott is probably right
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1994 K1100 LTSE + Blackbird

[Grunter]

[N41EF]

If you look for my thread with low temp thermostat, you'll find part numbers for a 170 degree thermostat with an air bleed port. Fill it to the neck, squeeze the lower hose a couple of times, top it off, and put the cap on. Remember to empty and flush the overflow as well.
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2014 R1200RT Water Cooled
2001 R1100S Light
1993 K1100LT. Nissan Ice Blue.(Gone)

[Flying Duck]

[jhinds]

My experience is from a bad seal as mentioned above. The oil seen through the glass level indicator was muddy brown/chocolate. I was 1500 miles from home so I drained the corrupted oil and coolant and refilled with 50/50 (distilled water/coolant) and added a can of sealant. The sealant worked till I got home but almost immediately broke down and left me with the brown color again.

Also, I replaced the thermostat. The new one was defective and the engine overheated. Had to replace it again. Test of defective thermostat showed it was not opening sufficiently.
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John
'76 BMW R90/6 >150K miles
'93 K1100LT >120K miles

[Grunter]

So far I have managed to do nothing except drain a small quantity of coolant from the system into a glass jar. Actually when looking at it from the side in daylight and not down the filler neck the colour isn't far off the original when I changed it last. I let it settle for a day and checked again, but there was lttle change. So perhaps I am concerned/worried about nothing.

Speaking to the local BMW agent the actual coolant concentrate should now be blue and not pink. This was changed for both bikes and cars a few years ago when it was found that the chemical composition of the blue coolant was better for both engines.

So, I am going to drain the system, remove the thermostat then back flush it as I said before. The same Thermostat will be replace as the temp control in UK seems to be normal, it was only the excessive heat build up when riding slowly up a steep road at 35 degrees C, for several miles caused the problem. I will also refill with the blue coolant perhaps later this week.

Looking at the instructions on the bottle containing the blue concentrate the only operational difference, is the blue should be changed every 2 years, whilst the pink was supposed to have a 5 year life.

My car, a Ford, still uses pink coolant, but my neighbours car, a 3 year old BMW 3 series is using blue.
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1997 K1100LT
1994 R1100RS

[Grunter]

I was out yesterday and unusually for the NE of Enland the temp reached the dizzy heights of 27C and true to form the bike once again started to over heat even at quite easy downhill stretches.

I drained the system again (It's getting boring now) and removed the thermostat. I did the recommended test of placing the 'stat in a pan of water and slowly brought it to 85 degrees F when it should have started to open - It didn't. I took it up to 95 degrees F and still no movement so I am now awaiting a new one sent by post. Hopefully that will be that sorted.
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1997 K1100LT
1994 R1100RS

[Inge K.]

[Grunter]