I AM EDITING THIS POST ON APR.17/10 SO THAT READERS DO NOT WASTE THEIR TIME WORRYING ABOUT SPECIAL COOLANT.
I did post the "new" information later in this thread but it seems that not everyone reads the whole thing.
WHEN I ORIGINALLY POSTED THIS IN 2006 I ERRONEOUSLY SUBSCRIBED IN THE "SILICATE FREE COOLANT" MYTH. WHILE SOME STILL BELIEVE IT IS REQUIRED IN LIQUID COOLED HONDA MOTORCYCLE ENGINES MADE IN THE '70S-'80S, I NO LONGER DO.
GL1000/1100 Cooling System Servicing:
Regular coolant is only good for a couple of years, and changing it is almost as important as changing the oil. Even the most expensive premium coolant is only good for 5 years. If your cooling system hasn't been properly serviced in the last couple of years, this would be a good time to do it. You should be changing the hoses, rad cap and thermostat too. If you don't it's like changing the oil without the filter - you are just wasting your time.
I assume you will be consulting a shop manual (Haynes, Clymer, Honda, or better yet 2 of them - if you don't follow what it says in one, you probably will follow the other.)
The rad hoses, thermostat, & rad cap can be bought at an auto parts store for a LOT less than you will pay at a bike parts store:
- Both rad hoses can be cut from a Dayco #71218 heater hose.
- The thermostat is the same one used in late '70s Civics (I have been using them in GoldWings & SilverWings for years).
- The rad cap is a standard automotive 13psi as used in a lot of cars & trucks. Curiously, the only car my wife has ever had that didn't use this exact same cap is the Honda CRV that she has now.
If you haven't already, you should replace the 0-rings at the ends of all the tubes &c in the cooling system.
There is also an o-ring in the thermostat housing that should be changed. I haven't found the right one anywhere except my Honda dealer.
If you leave the rad cap on while draining the old coolant, the stuff in the overflow tank will be drawn out too.
It's easier to change the hoses if you remove the rad. When you have it off, remove and throw out the thermostat, re-assemble the 'stat housing and flush the engine with a garden hose in the upper rad hose. Flush the rad too, and hose it off while you're at it. You wouldn't believe how much debris you can get out of the rad by spraying with a garden hose from the engine side. All those bugs &c that went in the front at highway speed and didn't come out the back for years are impeding the efficiency of your cooling system.
NOTE: If you are unsure whether the new coolant you will be using will be compatible with the old coolant it is imperative that you flush all traces of the old from your cooling system. Some modern coolants can form undesirable compounds when mixed with some other brands. Even if no odd chemistry occurs, mixing extended life coolant with compatible with regular (usually green) coolant will reduce its expected lifespan.
For reference, here is the original wording:
A word about coolants: You should use a coolant that is clearly marked silicate free. It should also be approved for use with "yellow metals" (like the brass in our rads).
There are many on the market that are fine, but do not under any circumstances use Prestone Long Life. Captain Jerry e-mailed them and they told him that their product is NOT COMPATIBLE WITH YELLOW METALS. I am sure Prestone Long Life is a fine product, but it just isn't suitable for use in our bikes.
I use Motomaster Long Life. I contacted Canadian Tire's tech support and they told me that it is specifically approved for use with yellow metals.
Here is the correction:
The more I learn the less I tend to believe that there is a need for silicate free coolants in these bikes. No-one has been able to find any mention of this in any Honda manual. It does, apparently, appear on the label of Honda coolant, but there is no evidence that it wasn't put there by someone in marketing (whose job is to sell people more than they need) as opposed to someone in engineering (whose job is to provide the information needed to keep things running properly).
When I first read on the forums that I should be using silicate free coolant (maybe 2001?) I had been using ordinary inexpensive green coolant that made no mention of silicates on the label in my GL1000 engine for 7 or 8 years with no ill effects but I assumed that those who were promoting the use of silicate free coolant had done their homework and I had just been lucky. At that time I contacted Canadian Tire tech support about their Motomaster Long Life coolant and was assured that it was safe for yellow metals so I started using it (that was a long time ago and they may have changed supplier or their supplier may have changed the formula since then).
Some Silicate free coolants are not compatible with "yellow metals" (like the brass in our rads) and could potentially do a lot of harm. Some long life (silicate free) coolants will, over time, dissolve the solder used to hold brass radiators together. Captain Jerry (who some of you may remember from the old MSN group) contacted Prestone at the time and was advised not to use it in a brass or copper rad.
A number of people have had water pumps fail shortly after the first time they changed the coolant and have been told that silicates in the coolant were to blame. I could claim the opposite: After all those years with cheap coolant, my 'Wing's original water pump failed a couple of years after I changed over to silicate free!! Should I blame silicates or the lack of silicates? The answer is neither - the bearing on the oil side let go. It was just plain old age - how many 25 year old cars do you know of that still have their original water pumps?
On the other hand, Joe-the-Bike (who lives in Queensland Australia and has owned his bike from new) put well over 210,000 Km on his CX500EC with no mechanical seal problems using regular bargain priced ethylene glycol coolant. He did replace the seal when he had the engine apart for a general rebuild in 2008 but it had not begun to leak.
I don't buy into the silicate free coolant myth any more and I no longer worry about whether I the coolant I buy has silicates (although almost all of it is either silicate free or low silicate these days).
I have since started using Nascar Advantage colour changing coolant because I like the fact that it tells me when it needs replacing (pink when new, replace when it turns amber). I can't remember if the label says anything about silicates.
Last edited by Sidecar Bob
on Sat Apr 17, 2010 5:47 pm, edited 3 times in total.