Coolant capacity.

[Mr.E]

Just finished another job on the list, empty out the cooling system and refill to ensure no air locks (was revving a bit too high when very cold) and noted I removed exactly 3lts from the whole system. Then put exactly 3lts back in and bleed the system properly.

The books say the capacity is 3.5lts so where the hell is that missing 1/2lt?

Found it... it remains in the bottom of the Radiator as the bottom hose is mounted about a 1/3 way up the right side of the Rad.
So that missing 1/2lt is in there - if anyone is wondering!

You'd thunk the bottom hose would be at the bottom of the Rad, seems to be plenty of room for it.

 

[tpasco1995]

Just finished another job on the list, empty out the cooling system and refill to ensure no air locks (was revving a bit too high when very cold) and noted I removed exactly 3lts from the whole system. Then put exactly 3lts back in and bleed the system properly.

The books say the capacity is 3.5lts so where the hell is that missing 1/2lt?

Found it... it remains in the bottom of the Radiator as the bottom hose is mounted about a 1/3 way up the right side of the Rad.
So that missing 1/2lt is in there - if anyone is wondering!

You'd thunk the bottom hose would be at the bottom of the Rad, seems to be plenty of room for it.

On radiator systems for most things, general practice is against placing the return hose at the very bottom of the system. The concern is any sediment in the system could be recirculated through the engine.

 

[Hondafarian]

Is it a good idea to somehow flush out the entire cooling system when changing the coolant?

 

[tpasco1995]

It's definitely not a bad idea, but it's a difficult one to do correctly.

The big issue is that if you get coolant/water out, that space is now air. You likely don't have an easy way to guarantee there's no air in those "invisible" bits of the system when refilling.

What you can absolutely do is flush a lot of water through the radiator. Pull the rad and blow from the higher hose connection through the bottom with a garden hose, then cycle through some distilled water from the fill cap a few times, before reinstalling and filling with coolant.

You can also do a partial flush. If 0.5 liters from a 3.5L system are old coolant, then topping off means total old coolant is only about 14.3% of the volume. Flush that out once and refill and you're down to 7.15%. The impact it's going to have is next to nothing.

 

[SMSW]

Very few folks do a flush of the cooling system as described in the HSM. It is simply too much trouble and there are few benefits. Instead, most of us just do like @tpasco1995 suggested, flush with water, drain, and add coolant then top off. IIRC, last time I did it, I just used a couple of changes of distilled water (a gallon of that only cost about a buck and a half), then filled up w/ Honda type 2, burped the system and filled it to the top. (Knowing me, I probably burped it a few times until the level in the radiator did not go down.)

 

[dduelin]

What I did during a coolant change was to siphon out the trapped coolant in the bottom of the radiator.

 

[etalors]

It's definitely not a bad idea, but it's a difficult one to do correctly.

You can also do a partial flush. If 0.5 liters from a 3.5L system are old coolant, then topping off means total old coolant is only about 14.3% of the volume. Flush that out once and refill and you're down to 7.15%. The impact it's going to have is next to nothing.

The Impact of having 14.3 % is also negligible. Doing it regularly is the key. Most folks don't drain the cylinder drain bolt as mentioned in the manual because only a few cc's comes out of there. The risk / reward is negligible. Not worth the trouble.

 

[Igofar]

If your servicing your coolant system, you should remove the radiator, change the T-stat and O-ring, Remove any/all black paint from inside the pipes, that tends to clog up things, and inspect all the surfaces of the pipes, make sure they are not pitted from coolant leaks (T-stat housing) snug everything up etc. I also flush all the dirt out of the cooling fins on the radiator while I'm doing this job. Most bikes that run hot, and come through the garage, have so much dirt jammed in the fins that you can't even see daylight through it.
Also make sure you don't over tighten the clamps on the radiator pipes themselves as they tend to be very soft, and easily damaged. If you find yours egg shaped from over tightening them, you can true them back up with a couple ball peen hammers. The large ball end in the pipe, while GENTLY tapping the face of the other hammer till they are round again etc.
You should also remove your overflow tank, and soak it with some CLR and a hand full of BB's or small nuts to clean all the shale out of the bottom of the bottle.
Also inspect the overflow tank for heat damage, cracks at the mounting point(s) or holes.

 

[motornut]

I haven't tried this on my ST yet and now that I think of it I will and will let you know what I find.
For a long time I have tested the cooling systems with a voltmeter. I drop the positive lead in the radiator and check for voltage. It does not take much to begin to erode the aluminum. With the radiator tubes and a bit of acidic coolant it becomes a good battery. On aluminum it particularly devastating, I have had a heater core in car leak in a short period of time, cured it with a ground wire attached to the core. It wasn't a coolant failure but it was bleeding from taking voltage from a body ground having a weak ground. I also took care of that but put the ground on core anyway.
The inside of the heater core turned black before it leaked. And of course more research is needed.

 

[Mr.E]

One other point I didn't mention was that I use Evans WATERLESS coolant - but I couldn't remember if I drained the cylinder bolt on the right side when setting it all up to remove all traces of the old antifreeze water coolant.
So this exercise also doubled up to ensure the old Evans Waterless coolant was replaced with close to 100% brand new Evans.
I now have no doubt that it will ever need doing again as it stays in the system for the life of the engine.

 

[docw1]

I also use Evan's. It does get darker with time, but I understand that is a feature. I changed it out once, after several years, when I changed the thermostat, but that was probably unnecessary. Great stuff.

 

[Mr.E]

Yep, I also noticed the old stuff was a darker red.

 

[CbridesST1300]

On radiator systems for most things, general practice is against placing the return hose at the very bottom of the system. The concern is any sediment in the system could be recirculated through the engine.

Who can help me do the coolant flush in Los Angeles?