ST1100 Coolant Flush procedure

ak85lp

ak85lp

(Paul)
Joined
Jul 12, 2009
Messages
232
Location
Franktown Ontario Canada
Bike
2018 VStrom 1000XA
Hi everyone:

Been awhile since I posted here as it is winter here in Ontario. -30 C or -22 F today for you folks using that. Either way it is bitter cold here today.

Which makes think about my coolant in the bike....Next spring I plan to replace the coolant with likely the Honda brand or the best Prestone brand I can get. Is there a good step by step listed here? I will look in my book to also compare but as you know there is always a step that would not be listed in the book based on past experiences from folks here.

Thanks
 
Well, the coolant drain plugs are behind the exhaust pipes and difficult to get to. You can do pretty good by draing out most of it through the drain plug at the bottom of the radiator, then unhooking the bottom coolant hose. then you can get out the last by blowing down through the filler neck (I think they call this the Ron Major flush). If you want ot get out the very last, then you could put in some distilled water, run it a bit, then drain that out. Just did it to put in Evan's waterless coolant. Thought I'd give it a try

Bill
 
I did mine last winter also. I have a 05 1300, so I don't know if the 1100 is the same, but if I remember right, the manuel says that there is one block drain plug. There is actually one on each side. I took the rad out at the same time, removed the fans, and soaked it in vinegar to clean the crap out of it, and flushed it out. It was all easy to do, and not to mention, its a goodtime to check all those hoses and connections behind the rad that you would never be able to see or get at. I also replaced my thermostat while I had access to that area. The temp bar had just started that two-three dance that fall. Add good antifreeze and distilled water, and you should be good to go.

John
 
Just replaced my water pump last summer due to supposedly okay coolant, which wasn't. Strongly suggest you go with the Honda coolant. Doesn't cost much more, is pre-mixed and good to -36.6 C. No mixing needed and made for the bike.

Remove the lower fairing panels before you do the flush. With the engine cold, open the drain cock on the rad first, positioning the slot downwards, THEN remove the rad cap to drain it, otherwise you'll get a messy draining session for a bit. As others have mentioned, drain each head by removing the 10mm plug bolt located at the bottom of each bank. They're behind the exhausts and are a bit of a pain to reach but a small socket with extension and universal makes short work of it. Remember to replace them.

If your coolant isn't totally expired, you don't have to flush out the engine, but if you really want to, just refill it with distilled or de-ionized water from a 4 litre bottle, run it for a brief minute then drain it again. While you're in between and if you feel really adventuresome I suggest that you remove and inspect your rad, both inside and out. You won't believe the junk that can get caught in the fins, (I have window screen on mine now which helps somewhat). I have found it to be mostly fine grit or sand that gets caught, requiring soaking in a tub and blowing out with air to clear it. It's also a good idea to take a close look at the condition of your hoses while you're at it.

My /99 is still OEM with regards to the hoses and there's almost 134k km on the bike now, so yours should still be in pretty good shape.

Oh yeah. Don't forget to siphon out your reservoir tank after you take off the overflow hose from the tstat housing, drain it back into the reservoir and inspect it for cracks.
 
Thanks everyone, excellent tips and yes I will likely go with the Honda antifreeze based on various posts I have read.
 
ak, you can get the Honda premix by the gallon at a car dealer rather than the quart size at the MC dealer. Cheaper that way.

I use Prestone premix, no silicates, from Walmart.

The Ron Major's Blow Job is the easiest/best way to get out most of the old stuff. Don't bother with the behind-the-exhaust-headers drain bolts. They are probably way stuck anyway.

Look closely at the drain hole from the water pump for the dreaded green residue. Hope ya don't see any. The original pump on STick went over 180,000 miles, changed it last spring along with her third timing belt and the idler pulleys. Bearing still feels okay but there is some dribble at the drain hole. Indicates the seal is gone/going.
 
I did my ST1100 coolant change last year using the UVIEW AIRLIFT system (search on Amazon for it). This device uses a compressor to create vacuum in the cooling system and removes virtually all of the remaining fluid. After draining the fluid, one hooks up the device, draws a vacuum and then drains the additional fluid. Repeat the previous step several times. Then the very cool feature is that one creates a vacuum in the system, and sucks the new fluid into the system with no mess or fuss or bother. I could post some photos of the process if needed. I also use this same tool on my Gold Wing and BMW F650.
 
Does the st1100 take any special kind of coolant? I just ordered motul inugel expert coolant for my 01 vfr 800 fi,that is the specific stuff for that bike,just wondering what the st1100 takes,
the motul inugel is ethylene glycol based and nitrate free.
 
broc11 said:
Does the st1100 take any special kind of coolant? I just ordered motul inugel expert coolant for my 01 vfr 800 fi,that is the specific stuff for that bike,just wondering what the st1100 takes,
the motul inugel is ethylene glycol based and nitrate free.
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You just have to make sure its "silicate Free". Lots of guys use Honda car antifreeze available from Honda car dealerships in their bikes, myself included. The only difference between that and Honda motorcycle antifreeze is the color, and the cost. Car version is blue, bike version is green. Car version comes in gallon jugs, bike version comes in quart bottles. Both are already mixed 50/50 in the jug.
Other guys on here have had good luck with Prestone. As long as its silicate free, your good.
 
Slasher said:
You just have to make sure its "silicate Free".
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+1... and FWIW am I using BelRay MotoCool since many, many years... it barely discolors, keeps the passages clean, etc...
And I perform a pretty low-tech approach for draining old coolant: as their hard to reach and the given risk of snapping them off I don't bother with the drain bolts on the engine case, instead I first drain through the white plastic plug on the LHS of the radiator and then I remove the LHS low coolant hose to get the rest out; even when I tilt the ST to the left side then, not much more fluid will drip out. Reconnect the hose (with a thin smear of silicone grease), inset the plastic plug (also its seal sees some silicone grease), place ST on sidestand and refill with my MotoCool, squeeze the hoses to belch out trapped air, start engine and let it idle (don't twist the throttle while rad cap is open), top off coolant as required and place rad cap once the thermostat opens. Let the engine idle till fan has cycled for the 3rd time so its fully warm to refill the expansion vessel to its max marking (will drop to the low line when cooled off).
 
I do close to the above procedure except I disconnect the lower hose, stick a long piece of garden hose into the radiator cap opening, fill the gap around the hose with a rag, and blow into the hose. This is known as the "Ron Major blow job" technique. It gets 90% of the coolant out. I then hook everything back up and fill with distilled water and start the bike, letting it run until the fan comes on. Pull the drain plug on the radiator (or the hose again) blow out the distilled water with the hose again. Fill with coolant as above.
 
I used my Shopvac in blow mode to do the job. Put the nozzle near the opening and any remaining coolant easily is ejected. Easily as in squirting a foot horizontally thus missing the drain bucket.:doh1:
 
MV_Dave said:
I used my Shopvac in blow mode to do the job. Put the nozzle near the opening and any remaining coolant easily is ejected. Easily as in squirting a foot horizontally thus missing the drain bucket.:doh1:
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I did the same thing, but blowing through a hose. I blew the stuff in a spray about 6 feet across my garage!:eek:
 
Slasher said:
I do close to the above procedure except I disconnect the lower hose, stick a long piece of garden hose into the radiator cap opening, fill the gap around the hose with a rag, and blow into the hose. This is known as the "Ron Major blow job" technique. It gets 90% of the coolant out. I then hook everything back up and fill with distilled water and start the bike, letting it run until the fan comes on. Pull the drain plug on the radiator (or the hose again) blow out the distilled water with the hose again. Fill with coolant as above.
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That exactly the way I do it and it WORKS!!!! But it does go about 4 to 5 feet on my garage so wised up and put a towel in front of the radiator w/Carole holding it!!!
 
gmast1100 said:
That exactly the way I do it and it WORKS!!!! But it does go about 4 to 5 feet on my garage so wised up and put a towel in front of the radiator w/Carole holding it!!!
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Thanks for bringing this part up, I covered my front wheel with antifreeze the first time I did this too! The key is a slow gentle blow not a blast!
 
Slasher said:
You just have to make sure its "silicate Free". Lots of guys use Honda car antifreeze available from Honda car dealerships in their bikes, myself included. The only difference between that and Honda motorcycle antifreeze is the color, and the cost. Car version is blue, bike version is green. Car version comes in gallon jugs, bike version comes in quart bottles. Both are already mixed 50/50 in the jug.
Other guys on here have had good luck with Prestone. As long as its silicate free, your good.
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Thanks Slasher, I have just copped on that the motul inugel expert is NOT silicate free,after all my research LOL
I have found prestone premixed in a local autoparts suppliers which is ethylene-glycol based and silicate free so I will use that instead.
the VFR and the ST both require silicate free coolant, so I'm gonna have a busy evening changing the coolant in both!
 
For anyone looking for a direct link to the Prestone AF2100 50/50 Antifreeze (already diluted) Link on Amazon, here it is.

If you're looking for the Prestone 100% antifreeze concentrate (non-diluted) , this is the link you'll need.

Hope this helps!! Winterize that sweet MC :)

Regards,
Vishnu
 
When I purchased my 1999 ST1100 (from a friend) I immediately flushed the rad, replaced the Thermo Sensor (unit that completes the electrical circuit to the fan when the coolant get's too warm), replaced the thermostat and, of course changed the coolant. I used Prestone and mixed 50/50 with distilled water. I did run a rad flush for 10 - 15 minutes of "easy" riding around the neighbourhood just to be sure. This was June of 2013. I have some pics that I've attached. I simply used the drain plug (photo) and flushed first with my hose using the city water pressure, then using pure distilled water...then refilling with proper coolant mix. Seems to be working just fine. My overflow bottle stays pretty much full, but does require the odd top up with about a cup of coolant every year. Cleaned Thermostat Housing Bolts.jpgKeyed Drain Plug.jpgNew and Old Thermostats.jpgRad Flush.jpgThermo Sensor.jpgNon Aerodynamic.jpg
 
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