How to flush your cooling system


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How to flush your cooling system

Postby WingAdmin » Sun Mar 22, 2009 8:51 pm



This is a procedure that should be performed every two to three years, and is a fairly simple (if messy) procedure. I recommend you have a large pan that can hold at least a gallon (preferably 4 or 5 gallons, as I use here) of liquid. The motorcycle engine must be COOL before doing this - do NOT attempt this procedure if the engine is hot!

Another warning: Do not leave open pans of coolant sitting out. Dogs and cats are attracted to the sweet smell of coolant, and will drink it given the opportunity. This will KILL them in a horrible manner - coolant is poisonous! Avoid expensive vet bills and unneeded strife, and bottle up your coolant as soon as it has cooled.

1. Remove the false tank. You can find instructions on how to do this here. Put your pan underneath the front of the motorcycle, directly behind the front wheel, and undo the coolant drain bolt, directly beneath the thermostat housing, and next to the oil drain bolt.

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2. The coolant will start dribbling out. Make sure your pan is right up as far as the front wheel, because the next step will have coolant gushing out.

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3. On the top of the bike, directly in front of the coolant reservoir, you will see the radiator cap.

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4. Remove the radiator cap. The coolant will start gushing out into your pan.

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5. Using pliers, squeeze the retainers on the reservoir hoses to loosen them, and pull them back. Then remove the hoses from the reservoir.

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6. Remove the bolt holding the reservoir to the frame of the motorcycle.

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7. Loosen the reservoir cap slightly, and pull the reservoir back to remove it. Open the cap and drain the reservoir into your pan. Clean the exterior of the reservoir.

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8. Replace and snug the coolant drain bolt.

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9. You will need two one-gallon jugs of distilled water (it must be distilled only).

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10. Using a funnel, pour the water into the radiator until it reaches the neck of the filler.

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11. Start the motorcycle and let it run for three to four minutes. Carefully monitor the filler neck and add water as required to keep the water level near the top. Stop the motorcycle, and remove the coolant drain bolt. Allow the water to drain from the motorcycle, the replace and snug the coolant drain bolt.

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12. Allow the motorcycle to cool until the engine is warm to the touch. We don't want to pour cold water or coolant into a hot engine. Repeat steps 10 and 11 again with another gallon of distilled water.

13. After draining the water from the engine the second time and snugging the coolant drain bolt, allow the motorcycle to cool until the engine is warm to the touch once more, then fill the radiator with coolant. This is where I prefer to use genuine Honda coolant, to preserve the delicate seals on my water pump:

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However, any modern pre-mix coolant usable on aluminum engines is acceptable, but it absolutely MUST be "silicate free."
This Prestone 50/50 premix should also work well:

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14. Note that the coolant must be "Silicate Free" as shown here. Coolant containing silicates will destroy the seals in your water pump in short order.

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15. Run the engine for several minutes, adding coolant to keep the coolant level near the top of the filler neck as it runs. You may need to rev the engine several times in order to get all the air out of the system. Each time the coolant level drops, add more coolant to bring it back up to the filler neck.

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16. Stop the engine and replace the radiator cap.

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17. Replace the coolant reservoir and fasten it to the frame.

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18. Reconnect both hoses to the coolant reservoir. Fill the coolant reservoir with coolant to the "Full" line.

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19. Start and run the engine until the cooling fan has cycled on at least twice. Monitor the coolant level in the reservoir over the next few trips you make on your motorcycle and add more as required.

20. Replace the false tank.



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Re: How to flush your cooling system

Postby thejagman54 » Mon Oct 05, 2009 10:24 am

Do you recommend using a premade flushing kit or will this harm the gaskets!!
thanks
Andy

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Re: How to flush your cooling system

Postby WingAdmin » Mon Oct 05, 2009 12:06 pm

I don't like using flushing kits, for the most part because they hook up to a hose or other water source that can (and usually does) put more pressure into the system than it is designed to handle. And when dealing with a 30 year old bike, I am loathe to do things to it that it is not designed to handle.

This is why I drain, then refill with distilled water, run the engine, drain, refill with water again, run the engine, drain, before finally filling with new coolant. The two cycles of distilled water flush any remnants of the old coolant out of the block and radiator.

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Re: How to flush your cooling system

Postby thejagman54 » Mon Oct 05, 2009 2:48 pm

Its a chemical flush I have, run for 10mins or so and dump. i think you have to then flush will plain water and dump then new 50/50 mix. i will check new mix contents after your article.
regards
Andy

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Re: How to flush your cooling system

Postby MIKEB13US » Mon May 31, 2010 7:14 pm

JUST DID THIS ,FEW DAYS AGO,WAY 2 EASY NOT TO DO...:lol:
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You can spend it anyway you wish,
But, you can spend it only once...............
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Re: How to flush your cooling system

Postby Livingthedream » Sun Aug 05, 2012 12:33 am

Excellent Instructions. Did mine for the first time today and it was so easy!! Total time was about an hour. Thanks so much for the step by step, made this a fun and satisfying experience!

No more overheating.. Awsome.

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Re: How to flush your cooling system

Postby aznyaz » Fri May 10, 2013 6:22 am

I'm in the process of a carb rebuild and when I took them off I noticed I had a leak coming from the left side crossover (coolant) tube at the elbow into the head. Since I've noticed this now, it's seems to be the perfect time to replace the 'O' rings and gaskets on both tubes and elbows, which requires flushing the cooling system. Is there a way to get a decent flush without the engine running? My guess is no since the thermostat won't open. So, on to my next question. Should I just flush enough coolant out to get the level below the crossover tubes just to fix them and top off with fresh coolant to get it back to the proper level?

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Re: How to flush your cooling system

Postby aznyaz » Fri May 10, 2013 8:17 am

I think I just answered my own question when I looked at the T'stat assembly this morning. There's probably no need to flush the system right now. Since the T'stat is closed, the only coolant that will drain is just what's in back of the T'stat housing and crossovers and elbows.

Would like to hear what anyone else thinks about this, and if there are any secrets or procedures in re-assembling the crossovers.

Thanks.

MJ

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Re: How to flush your cooling system

Postby WingAdmin » Fri May 10, 2013 8:07 pm

aznyaz wrote:I think I just answered my own question when I looked at the T'stat assembly this morning. There's probably no need to flush the system right now. Since the T'stat is closed, the only coolant that will drain is just what's in back of the T'stat housing and crossovers and elbows.

Would like to hear what anyone else thinks about this, and if there are any secrets or procedures in re-assembling the crossovers.

Thanks.

MJ


I'm pretty sure the thermostat never closes completely (doesn't seal) so you will end up draining everything.

Use vaseline on the O-rings when reassembling, to make sure you don't pinch or roll one. Make sure any corrosion or crusty gunk is removed from the tubes first before reassembling.

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Re: How to flush your cooling system

Postby aznyaz » Fri May 10, 2013 9:30 pm

Thanks. So I should at least empty it to a point below the T'stat, or should I just empty it completely? I really can't do a complete flush at this point since the carbs are off and the bike's not running. All I can do is just fill it up with new coolant and do full flush later.

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Re: How to flush your cooling system

Postby WingAdmin » Sat May 11, 2013 9:07 pm

aznyaz wrote:Thanks. So I should at least empty it to a point below the T'stat, or should I just empty it completely? I really can't do a complete flush at this point since the carbs are off and the bike's not running. All I can do is just fill it up with new coolant and do full flush later.


Just empty it all, then you can do the flush later, and have nice clean coolant.

When I have drained coolant from a bike, I will put a piece of tape across the ignition just in case I were to forget there is no coolant in it later on. :)

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Re: How to flush your cooling system

Postby aznyaz » Sat May 11, 2013 11:38 pm

Good advice. Thanks!

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Re: How to flush your cooling system

Postby IceBear82 » Fri Aug 02, 2013 2:57 am

Cool beans this is a step i look forward to sounds easy... lol :D

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Re: How to flush your cooling system

Postby Ragz » Fri Aug 02, 2013 8:34 pm

Just bought a 1980 GL1100 and it overheats quickly. Does anyone think flushing will help ? Im going to try but if any other ideas.....I'm open to suggestions. This is my first Goldwing. I love this site. So glad I joined.
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Re: How to flush your cooling system

Postby aznyaz » Sun Aug 04, 2013 12:04 am

I'm no expet here but it could be low coolant level, stuck thermostat, etc. I'm sure other will chime in.

Stick with this site, I've learned a lot here.

MJ

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Re: How to flush your cooling system

Postby WingAdmin » Tue Aug 13, 2013 10:18 am

Blocked radiator, failed thermostat, failed radiator cap, failed (or failing) water pump, there's quite a number of things that can cause overheating.

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Re: How to flush your cooling system

Postby Ragz » Tue Aug 13, 2013 11:04 am

Thanks for the advice. I have replaced the thermostat which was stuck in the open position and it seems to have fixed the problem. There is just something about doing this stuff yourself that is so fulfilling. I still have a lot to do but this was the most important thing. Thanks again.
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How to flush your cooling system

Postby wingone01 » Sun Jul 13, 2014 9:24 pm

I have a 6.0 Ford Diesel. A primary maintenance task is to flush the radiator and block. This is quite the ordeal but worth it for peace of mind and a happy engine. Now back to the Goldwing forum....

I know this is an older post but do you use any cleaning agent(s) to flush the cooling system? That is why I mentioned the diesel flush above...you used two different cleaning agents with full flush and drain in between each one and rinse, rinse, rinse before refilling with antifreeze. You pulled the t-stat out while doing all of this to make sure you cleaned the entire system.

I was thinking of doing something similar with my wing. Although the bike is 20-years old and I do not have any previous maintenance history on the bike so I am trying to hit all of the basics to establish a maintenance history. Your website has (is) a great benefit!

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Re: How to flush your cooling system

Postby WingAdmin » Mon Jul 14, 2014 2:22 pm

wingone01 wrote:I have a 6.0 Ford Diesel. A primary maintenance task is to flush the radiator and block. This is quite the ordeal but worth it for peace of mind and a happy engine. Now back to the Goldwing forum....

I know this is an older post but do you use any cleaning agent(s) to flush the cooling system? That is why I mentioned the diesel flush above...you used two different cleaning agents with full flush and drain in between each one and rinse, rinse, rinse before refilling with antifreeze. You pulled the t-stat out while doing all of this to make sure you cleaned the entire system.

I was thinking of doing something similar with my wing. Although the bike is 20-years old and I do not have any previous maintenance history on the bike so I am trying to hit all of the basics to establish a maintenance history. Your website has (is) a great benefit!


I've never used anything but simple distilled water to flush an aluminum bike engine - but then, I change my coolant often enough that there really isn't the opportunity for sludge or dirt to collect.

The Honda service manual recommends a flush with distilled water, if that is of any help.

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Re: How to flush your cooling system

Postby wingone01 » Mon Jul 14, 2014 7:02 pm

Thank you.
I will wait until I see what condition the coolant is when I drain it. If it looks good, I may just do a couple of distilled water rinses and fill with new coolant/water. The temperature gauge looks fine and never reaches the 1/2 way mark so I do believe the system is relatively clean and functioning correctly. If it does not look right, I will go ahead and use the system cleaner. I know you do not like the garden hose flush system. I am not using that type but fill with the cleaning agent and run the engine for a short distance, then rinse, rinse and fill.

As I mentioned I am trying to start a base line for maintenance history and am trying to get everything to factory spec or better. I have new timing belts that should be delivered any day now. I have changed the oil and will change the plugs at the same time I do the timing belts. I have new cruise and compressor filters in addition to new desiccant that will be changed during my next down time.

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Re: How to flush your cooling system

Postby jbills31 » Sun Sep 14, 2014 2:43 pm

Thank you everyone for how to do this flush on the coolant system, i took it one step further and ran 4 gallons of distilled water through, since the pervious owner was not able to tell me when he last flushed the system.

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Re: How to flush your cooling system

Postby thboyd29 » Tue Oct 21, 2014 3:43 am

Doing the coolant flush yesterday per the article's instructions, and stumbled across something. The service manual says that the cooling system for a GL1100 holds 3.6 quarts. However, during the flush process I found that I was only adding about 2.5 quarts of distilled water during each flush/fill cycle, meaning that (if the manual was right) there's an extra quart or so of water remaining in the engine after draining. Now - I know that you're supposed to use a 50-50 mix of coolant/distilled water. I also know that the Honda coolant I bought is pre-mixed to that 50-50 ratio. That means that, when you take the extra 1.5 quarts of plain distilled water remaining in the system from the last flush and add the 2.5 quarts of 50-50 mix to the system (because that's all it'll take), you'll end up with a considerably weaker-than-optimal coolant mix. This leaves me with three questions:
1. Since the system isn't completely draining, could I be doing something wrong? The bike is on the center stand and on level ground. As noted in the article, coolant gushes out when the rad. cap is removed.
2. If I'm doing everything right and the system *can't* be completely drained, wouldn't it be better to install 1.8 quarts of full-strength coolant after the final flush, then top off with distilled water to reach the desired 50-50 mix?
3. Does Honda sell a full-strength version of their coolant? All I've ever seen is the 50-50 mix.
Thanks for any insight you might lend.
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Re: How to flush your cooling system

Postby WingAdmin » Tue Oct 21, 2014 3:30 pm

thboyd29 wrote:Doing the coolant flush yesterday per the article's instructions, and stumbled across something. The service manual says that the cooling system for a GL1100 holds 3.6 quarts. However, during the flush process I found that I was only adding about 2.5 quarts of distilled water during each flush/fill cycle, meaning that (if the manual was right) there's an extra quart or so of water remaining in the engine after draining. Now - I know that you're supposed to use a 50-50 mix of coolant/distilled water. I also know that the Honda coolant I bought is pre-mixed to that 50-50 ratio. That means that, when you take the extra 1.5 quarts of plain distilled water remaining in the system from the last flush and add the 2.5 quarts of 50-50 mix to the system (because that's all it'll take), you'll end up with a considerably weaker-than-optimal coolant mix. This leaves me with three questions:
1. Since the system isn't completely draining, could I be doing something wrong? The bike is on the center stand and on level ground. As noted in the article, coolant gushes out when the rad. cap is removed.
2. If I'm doing everything right and the system *can't* be completely drained, wouldn't it be better to install 1.8 quarts of full-strength coolant after the final flush, then top off with distilled water to reach the desired 50-50 mix?
3. Does Honda sell a full-strength version of their coolant? All I've ever seen is the 50-50 mix.
Thanks for any insight you might lend.


As long as the bike is on the center stand, and there is nothing blocking an internal passage, removing the coolant drain bolt will drain ALL of the coolant from the radiator and engine.

Keep in mind that when Honda specifies 3.6 quarts as the capacity of the cooling system, it's including the coolant reservoir. So you will get around 2.5 - 2.6 quarts into the engine after it has been burped, and the remainder goes into the coolant reservoir, for a total of 3.6 quarts.

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Re: How to flush your cooling system

Postby thboyd29 » Tue Oct 21, 2014 10:20 pm

WingAdmin wrote:As long as the bike is on the center stand, and there is nothing blocking an internal passage, removing the coolant drain bolt will drain ALL of the coolant from the radiator and engine.

Keep in mind that when Honda specifies 3.6 quarts as the capacity of the cooling system, it's including the coolant reservoir. So you will get around 2.5 - 2.6 quarts into the engine after it has been burped, and the remainder goes into the coolant reservoir, for a total of 3.6 quarts.

Thanks for the quick reply. I did a quick check, and it takes 3 cups (0.75 quart) to fill my coolant tank to the "full" mark. Doing the math, 3.6 - 2.6 - 0.75 = 0.25 quarts unaccounted for - only 1 cup, which certainly could be trapped in the engine somewhere, but it should be OK so I'll go ahead with installing the Honda pre-mix (since I've already got it) rather than go look for an appropriate full-strength coolant (which, according to my local (75 miles away, but they do a lot of GW work...), they don't remember ever seeing a Honda coolant that wasn't pre-mixed).

Thanks again.

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Re: How to flush your cooling system

Postby bobbybiscuit » Sun Mar 29, 2015 10:58 am

Very interesting article.

I bought my bike in 2013 as a running bike but it was very well.

I decided to replace the thermostat and found out when taking it to bits that my bike did not have one . So i found one of the recommended alternatives and fitted that....well so I thought. The trouble was that when i put in the thermostat the thermostat housing would not sit properly and would not seal except with masses amounts of silicon. There was a gap on both sides and looked like it did not fit correctly (snuggly). Anyway when tightening the bolts it compressed slightly my thermostat and mishaped it slightly - not very much though.

I run the bike now without a thermostat. Its takes a bit longer to warm up but I dont have any problems now.

It makes me wonder whether the previous owner through the rebuild put in another old radiator with different end fitting (thermostat housing cover). Looking at the pic on here it certainly does not sit as shown ie there is a gap between the bolt hole on thermostat cover and the casing - really odd.




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