Coolant flush today - just venting

jacMA

jacMA

Joined
Dec 30, 2022
Messages
37
Age
60
Location
Boston
Bike
2000 ST1100
Okay, let me just start by saying that I love my ST1100. That said, why is it the most painful bike I've done to flush the coolant!!

This is what you need to take off to drain the coolant and remove the expansion tank

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These screws

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As it is, I always hate doing coolant, but trying to slowly get ready for my trip

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Removing that bodywork shouldn't take but about 15 minutes on a slow day ... ;)
I don't understand why you removed the lower left fairing or the left fairing pocket. :think1:
Unless you are doing a 'block' drain and there are easier ways to that - plus it is sort of a waste of time for the amount of coolant in there.
 
I did the left to get at the radiator drain plug, and wanted to remove the hose so I wouldn't have to take out the head screws. I don't know when the original owner did this last, so wanted to drain it well. It was using the old green and I was putting in the updated blue. I know they work fine together, but I wanted as much as possible out.
 
I drained the radiator, refilled with water, ran bike 15 min., drained again and filled with new coolant. I much rather ride than wrench and fortunately I'm not cdo or ocd!
 
FWIW, on my BMW F800GT, I was planning to have the coolant changed when I brought it in for the valve check. The mechanic talked me out of it. He said BMW no longer recommends changing the coolant ever.

Chris
 
Next time work on an NT or NC...

...then you have reasons to complain...

The ST still has nuts and bolts to hold each panel individually, darn "modern" bikes are now mostly just clipped together... you need a LEGO block separator...

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When I did the drain and refill (I didn’t run distilled water in mine as the coolant from the timing belt change 20K miles ago still looked like new- that was Prestone 5 yr/100K mileage coolant), it was a little work taking it all apart, but now that it’s done, I’ll leave it alone for quite a while (used Prestone 15 yr/350K mile coolant)- the last time I did it was 2017 and probably won’t do it again til another 8-10 years from now. I think the difference in years/ mileage of the coolant is the concentration (the one I recently used is 56/44 antifreeze to water content).
 
Erdoc48 said:
I’ll leave it alone for quite a while (used Prestone 15 yr/350K mile coolant)- the last time I did it was 2017 and probably won’t do it again til another 8-10 years from now. I think the difference in years/ mileage of the coolant is the concentration (the one I recently used is 56/44 antifreeze to water content).
Click to expand...

years ago I looked at my 1100 sitting in the garage and had the revelation "when did I last change the coolant, I can't even remember". It somehow just slipped my mind for a long time, probably 8, 10 years, maybe a bit longer. When I drained it, the coolant was orangey in color from rust so I crossed my fingers and hoped a flush and refill would put things back in order. It didn't. Bottom line was it had ruined the water pump. It didn't fail right away, but later on it finally started making squeaky bearing noises. It was about timing belt replacement time anyway, so I went in there and replaced everything. The impeller blades on the water pump had corroded away such that instead of bending 90 degrees they were just straight metal stubs. IDK how it was pumping water like that, but it was able to do it reasonably well.

I understand coolant technology has improved over the years, but given the lack of replacement water pumps I'd rethink your coolant change interval just to be on the safe side. Its really easy to just drain it from the radiator drain valve, and fill it back up every few years. I think the fact that you don't get all of the old coolant out isn't going to be a problem if you do it more often.
 
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