Coolant cocktail might be too good

[1Jumper10]

So I'm a new BMW owner of a neglected 2018 XR. I bought the bike 3 weeks ago out in New Jersey with 350 miles on it. I'm the third owner.  I drove it home from NJ to Michigan, stopping in Harrisburg Pennsylvania to change the oil. The bike still had not had its first service done and was limited to 9000rpm. I had 600 miles to get to know it. I noticed that it ran hot like my Tuono. On the highway it would run about 175 degrees F.  Stops for gas it would rise to 200 or so. Not abnormal for a performance bike and about the same as my Touno.

Once I got it home I had to replace the fork seals and I had some downtime waiting for parts. In which time I decided to flush out the coolant and replace it with the Coolant Cocktail noted at other places on this and other bike forums. My cocktail was a 60/40 blend of Honda type 2 antifreeze and deionized water with about 2ounces of Redline Water wetter.

Fast forward to today. Today was the day it was going to the dealer for it's first service. A 90 mile morning ride. Air temp was 56deg F, a little chilly. I always keep careful track of my engine temp. I warmed the bike up a little and got started. Watching the temp it barely got to 150F! If I slowed down for a speed zone it would hit about 170 but as soon as speed picked up it would plummet back down to around 150.  Even running 90mph on the highway it would only get to 168 occasionally.  I know it's not good for the engine to run too cold and I'm pretty sure the thermostat opens at 168F.  I've got another ride planned for tomorrow and it should be warmer so I'll watch it again. It's pretty crazy how much cooler that cocktail is.

[Salish1000]

Welcome to the coolant cocktail club! Your experience is similar to mine. I came to the XR from a recent Concours 14 where the coolant cocktail is widely used. You are using a higher % of coolant than the standard cocktail recommends. Bottom line, any liquid cooled bike has a thermostat designed to keep the engine at a good minimum operating temperature. You aren't going to do any harm. When it is cool and wet here in the rainforest PNW, my XR will hover in the 160's. In summer, in traffic, it sits around 210 and pushes up against 217 even with the cocktail.

One of the great benefits is not only temperature, but the reduction in hot spots around the cylinder heads. Those that know more than I do, on hot performance bikes, say that is a real benefit. I also speculate it is much better for our water pumps, stopping the pump from leaking on my bike.

[1Jumper10]

Yeah so far it seems like a game changer. I went with a higher percentage of coolant for the freeze protection. It's a little colder here in MI than the PNW. 

[Salish1000]

Originally Posted by 1Jumper10

Yeah so far it seems like a game changer. I went with a higher percentage of coolant for the freeze protection. It's a little colder here in MI than the PNW.

That's the truth. I know folks out in hard freeze country mix up their cocktail for winter vs. summer. I think the classic mixture has like 15% antifreeze. I'm forgetting the minimum amount recommended for temps below 20. Here in the PNW we get maybe one week all winter below 20, with mostly above freezing. We can ride 355 days a year with only 290 of them being 45 and raining.

[1Jumper10]

Another cool day, about 70 deg F. Bike runs about 155 on the highway.  It's pretty amazing how fast the heat transfer is. Watching the temp gauge, sometimes it will skip an increment it's changing so quickly.

[Salish1000]

I'll add that on air cooled Guzzi's, the oil temperature is a real concern in cool places like here or other northern US locations in cool weather. People install oil cooler bypass valves and oil temp gauges to make sure their oil warms up enough to reduce condensation. On my 8V Stelvio, you would get something called pink mayonnaise inside the valve covers because they weren't getting hot enough consistently enough in our 40 degree weather to cook off the water. The new V100 being water cooled is a huge change for Guzzi, and a real benefit for those of us who live in cool climates. The whole system is based on the thermostat temp and fan temp. The former for minimum temps, which our XR's hit easily even in cool weather, and the latter for obvious upper limits.

The originator of the coolant cocktail, to my knowledge, is a famous Concours 14 mechanic going by Steve in Florida. Riding that big 1400 in constant 95 degree temps and 90% humidity motivated his solution.

[1Jumper10]

A little update now that hot weather is here.  The bike temps are normal for what I'm used to and it definitely sheds heat quickly.   I'm impressed with the cocktail overall. No complaints.

I watched the level in the radiator overflow tank pretty carefully and noticed it was losing level gradually.  At first I chalked it up to the coolant system getting some entrapped air out after the coolant swap.  After adding once and still losing level, I checked under the bike and noticed a little wet around the weep hole under the water pump.  So, this will be the next thing I fix.   
I'll keep topping off the coolant for the rest of this season and tackle the job this fall. 

[Crosshairs]

Call me skeptical but it sounds like a placebo effect  to me ....anyone have any verifiable proof this "cocktail" lowers temperatures?
 Im guessing no.

[1Jumper10]

Pretty sure no one said it lowers temperature.  Its just more efficient at heat exchange which makes it a better coolant.  But which also makes it a poor anti-freeze.  I need a good coolant more than I need freeze protection though.

[Salish1000]

Originally Posted by Crosshairs

Call me skeptical but it sounds like a placebo effect  to me ....anyone have any verifiable proof this "cocktail" lowers temperatures?
 Im guessing no.

Yes, it does. On bikes with more heat issues than the XR, it's a well known cure. Especially the big 1400 Concours 14 crowd. Those folks that live in hot places like Florida, swear by it to lower the temperature on their bikes.

I just did a 750 mile day through 90-100 degree temperatures and over many passes and my engine temp sat around 185-195. Stopped in traffic in Moab at 100 degrees, the fan didn't even come on. Never got above 212F.