filled coolant entirely from reserve tank, how to bleed air?

[qcpcx]

So I messed up and filled the entire coolant system from the reserve tank. I then realized I should have filled radiator first and ran it with the radiator cap off to bleed the air. My question now is how do I bleed the system? Taking the radiator cap off now causes a leak from the reserve tank. Does running it with the reserve tank lid open allow the air to bleed or should I drain it to the point where I can idle it with the radiator cap off to bleed correctly, then top off the reserve again?

This is my first time trying to change the coolant, just bought it used and given that it is a 2013 I had a feeling it needed it. I appreciate the help.

[springer1]

......... filled the entire coolant system from the reserve tank.

I might be wrong, but if you tried to do that, I'm pretty sure you didn't fill the coolant system at all, rather just the reserve tank. I would not run the scoot until you first fill the system first.

[qcpcx]

I loosened the radiator cap after pouring most of a Honda coolant bottle into the reserve tank and it started leaking from the radiator cap location so it certainly seems like it did pass into the system, but I definitely appreciate the caution about that. If I need to completely remove the radiator cap and allow the reserve to drain out, I can do that. Then bleed by idling with radiator cap off, then replace cap and refill reserve. I know most know these steps but I am listing them to ensure I don't screw up twice.

[springer1]

OK understood. But really, I’d remove the radiator cap and ensure the radiator is full before proceeding. Do a search on “ coolant change “ or similar and read up on related issues and how to proceed. Here’s one thread .....

http://www.hondapcx.org/viewtopic.php?f ... eed#p79603

Note that most radiator caps have a pressure seal below where the overflow tube leading to the reserve tank connects. So it’s necessary to remove the cap not just loosen it in order to fill the radiator.

[qcpcx]

OK understood. But really, I’d remove the radiator cap and ensure the radiator is full before proceeding. Do a search on “ coolant change “ or similar and read up on related issues and how to proceed. Here’s one thread .....

http://www.hondapcx.org/viewtopic.php?f ... eed#p79603

Note that most radiator caps have a pressure seal below where the overflow tube leading to the reserve tank connects. So it’s necessary to remove the cap not just loosen it in order to fill the radiator.

Thanks. To get back to the point where I am topping off the radiator only, how would you proceed with draining the reserve tank? My first impression is to simply open the radiator cap entirely and catch what I can below the scoot. Then, follow the topping off and bleeding instructions as I should have to begin with...?

[Oyabun]

Thanks. To get back to the point where I am topping off the radiator only, how would you proceed with draining the reserve tank? My first impression is to simply open the radiator cap entirely and catch what I can below the scoot. Then, follow the topping off and bleeding instructions as I should have to begin with...?

I'd pinch the overflow pipe (eg. With a strong binder clip) to not loose coolant, and do the whole radiator filling and bleeding procedure. When finished remove the binder clip and live happily ever after.

[qcpcx]

Thanks. To get back to the point where I am topping off the radiator only, how would you proceed with draining the reserve tank? My first impression is to simply open the radiator cap entirely and catch what I can below the scoot. Then, follow the topping off and bleeding instructions as I should have to begin with...?

I'd pinch the overflow pipe (eg. With a strong binder clip) to not loose coolant, and do the whole radiator filling and bleeding procedure. When finished remove the binder clip and live happily ever after.

Thank you Oyabun, Great point!! To confirm, you mean pinch the connection tube that goes to the radiator from the reserve tank? Hopefully I can reach in there enough to clasp the hose. Now I can access the radiator without wasting coolant...

[Oyabun]

To confirm, you mean pinch the connection tube that goes to the radiator from the reserve tank?

Affirmative. I mean to pinch the small diameter tube going from the radiator cap to the reserve tank.

[qcpcx]

To confirm, you mean pinch the connection tube that goes to the radiator from the reserve tank?

Affirmative. I mean to pinch the small diameter tube going from the radiator cap to the reserve tank.

well, I tried the binder clip on the hose, it didn't hold tight enough (should have used a vice grips ) so when i opened the radiator cap, some of it filled the radiator and some overfilled onto the side of the radiator and onto the floor. I used a pipette to remove some material so that it was not overflowing (lowered to the filler neck) and then started the engine with the radiator cap off to bleed per manual instructions 4 to 5 minutes and a little throttle snapping. I did not notice any bubbles come through the liquid.

1. Is it safe to assume that it is bleed properly if I did not see any bubbles?
2. I know the coolant has some rust inhibitors in it, so is it 'fine' that some of it spilled out onto the sides of the radiator and onto other parts? I was not sure if I should removed the side panel and radiator cover again to clean up any residues?

[springer1]

1. Is it safe to assume that it is bleed properly if I did not see any bubbles?
2. I know the coolant has some rust inhibitors in it, so is it 'fine' that some of it spilled out onto the sides of the radiator and onto other parts? I was not sure if I should removed the side panel and radiator cover again to clean up any residues?

If the engine got hot enough that the thermostat opened and allowed the water pump to circulate the antifreeze - then you should have been able to see that flow and bubbles in the radiator’s neck - especially when you would burp the throttle. If that was the case, then reattach the cap and refill the reserve tank. The system should do its job and expel any residual air onto the reserve when the engine heats up and then suck back fluid from the reserve when it cools. If you did not see the antifreeze flowing and bubbles expelled then it wasn’t so redo it until you do.

After you’re satisfied, watch if the reserve tank level drops as the engine cools after the next few rides - and if it does add more into it. Antifreeze can be sticky so when all is cool it’s good to wash off any residue.

[springer1]

I should add it’s a small system so don’t expect to see the amount of flow rate or bubbles like you would in a car or truck. But it is important that the engine got hot enough to open the thermostat and then throttle burps would show fluid circulation and expel any air in the system.

[qcpcx]

1. Is it safe to assume that it is bleed properly if I did not see any bubbles?
2. I know the coolant has some rust inhibitors in it, so is it 'fine' that some of it spilled out onto the sides of the radiator and onto other parts? I was not sure if I should removed the side panel and radiator cover again to clean up any residues?

If the engine got hot enough that the thermostat opened and allowed the water pump to circulate the antifreeze - then you should have been able to see that flow and bubbles in the radiator’s neck - especially when you would burp the throttle. If that was the case, then reattach the cap and refill the reserve tank. The system should do its job and expel any residual air onto the reserve when the engine heats up and then suck back fluid from the reserve when it cools. If you did not see the antifreeze flowing and bubbles expelled then it wasn’t so redo it until you do.

After you’re satisfied, watch if the reserve tank level drops as the engine cools after the next few rides - and if it does add more into it. Antifreeze can be sticky so when all is cool it’s good to wash off any residue.

Thanks for the guidance Springer1! I didn't see any physical bubbles, but I did see the coolant level rise a half inch or more (it rose from the filler neck line nearly to the top of the opening again) after 3 minutes of it running and I saw steam coming from the area so it did appear that the thermostat opened. Also it did appear to circulate a small amount. I could take the cap off and heat it up again for a few minutes to be safe... what is your general impression on that?

I am asking because I want to be sure I don't cause any harm by leaving air inside since it is my first time. Overall I think I followed the steps correctly on my second attempt

I will give it a wash without removing the panels. It certainly has turned into a sticky mess. Thanks!

I really appreciate the help this community has already provided. Learning a lot along the way.

[springer1]

! I didn't see any physical bubbles, but I did see the coolant level rise a half inch or more (it rose from the filler neck line nearly to the top of the opening again) after 3 minutes of it running and I saw steam coming from the area so it did appear that the thermostat opened. Also it did appear to circulate a small amount.

Yes, its a small system. If you burped the throttle to rev the engine a few times when it was steaming and appearing to circulate, then it should be ok. It might be good idea to make your next few trips long enough to heat up the engine but not so long as extended trips, followed by letting the scoot totally cool.

That will allow the system to expel any remaining air to the reserve as it heats up and then refill the radiator back from the reserve as it cools down. Watch the level of the reserve tank as it may drop and need refilling as it refills the radiator system (replacing any displaced air with antifreeze).

[springer1]

If you burped the throttle to rev the engine a few times when it was steaming and appearing to circulate

Note this is the critical part. Don't be gentle, get it hot & burp the throttle to rev the engine enough to make the water pump forcefully circulate and get trapped air out.

[qcpcx]

If you burped the throttle to rev the engine a few times when it was steaming and appearing to circulate

Note this is the critical part. Don't be gentle, get it hot & burp the throttle to rev the engine enough to make the water pump forcefully circulate and get trapped air out.

Thank you for emphasizing that... I would say that I was fairly gentle with it, it tries to lurch forward or sideways unless I hold the brakes. I suppose I was scared to over do it. I can pop the cap back off an rev it more... Hard to know how much throttle to give it

[springer1]

If you burped the throttle to rev the engine a few times when it was steaming and appearing to circulate

Note this is the critical part. Don't be gentle, get it hot & burp the throttle to rev the engine enough to make the water pump forcefully circulate and get trapped air out.

Thank you for emphasizing that... I would say that I was fairly gentle with it, it tries to lurch forward or sideways unless I hold the brakes. I suppose I was scared to over do it. I can pop the cap back off an rev it more... Hard to know how much throttle to give it

Yes, for goodness sakes, don't run if off the center stand or over do it ! Be safe.

[qcpcx]

I bled the radiator again and put everything back together. Filled reserve and took two short drives. No change at all in reserve levels. i think I'm set! Thanks for the help!