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Coolant overflowing

Posted: Sun Jun 23, 2013 12:07 pm
by DJTEMEKA
Hiya

I've looked online regarding these issues but haven't found anything that helps yet.

VFR400 NC30
coolant level is in range BUT lets a fair bit out after a run. The fluid leaves out the overflow pipe under the bike.
It first happened on the Hastings run but we were in stand still traffic for ages and the bike ran very hot.
However, the missus went to work today and it happened again after topping it up and taking the rad cap off and revving it to get air bubbles out. The journey was London but not heavy traffic as its Sunday. 12 miles or so.

Dip stick shows no signs of milkiness and neither does the rad cap.

Any ideas as to what can be causing the coolant to leave a puddle under the bike?
We haven't checked to see if the fan runs or not yet but the missus says the bike didn't run too hot today.

another Q..

any idea on how to get the fan to kick in earlier as (Is it just me) the VFR tends to run fairly warm as standard? I've always rode nakeds and the lack of fairing helps cooling somewhat.


thankyou :)

Re: Coolant overflowing

Posted: Sun Jun 23, 2013 3:18 pm
by speedy231278
Did you check the coolant level in the rad and also in the expansion tank after everything had cooled down. I've often found that if you refill the system, you can seemingly put too much in. The first time the bike gets really hot, you switch off and loads of coolant pees out under the bike. If you check the rad and expansion tank when the bike is cold, and the rad is full, and the tank is between the high and low lines, chances are there was just a little too much in there. I've never had it blow out stuff more than once after over filling, it's almost like the bike is telling you where the right level is.

Re: Coolant overflowing

Posted: Sun Jun 23, 2013 3:36 pm
by Neosophist
DJTEMEKA wrote:Hiya

I've looked online regarding these issues but haven't found anything that helps yet.

VFR400 NC30
coolant level is in range BUT lets a fair bit out after a run. The fluid leaves out the overflow pipe under the bike.
It first happened on the Hastings run but we were in stand still traffic for ages and the bike ran very hot.
However, the missus went to work today and it happened again after topping it up and taking the rad cap off and revving it to get air bubbles out. The journey was London but not heavy traffic as its Sunday. 12 miles or so.

Dip stick shows no signs of milkiness and neither does the rad cap.

Any ideas as to what can be causing the coolant to leave a puddle under the bike?
We haven't checked to see if the fan runs or not yet but the ssus says the bike didn't run too hot today.

another Q..

any idea on how to get the fan to kick in earlier as (Is it just me) the VFR tends to run fairly warm as standard? I've always rode

nakeds and the lack of fairing helps cooling somewhat.


thankyou :)
How old is your rad-cap.

Don't forget that it is desigednt to let some coolant into the bottle when it is hot, but an old rad-cap can leak / not hold pressure.

There is no need to make the fan come on any earlier. It only comes on when the bike is in danger of over-heating.

The bikes run hot but no damage or ill effect will occur, that is how they are designed.

Re: Coolant overflowing

Posted: Sun Jun 23, 2013 5:57 pm
by DJTEMEKA
missus called up saying that the coolant was leaking again. gets home and shows the rad cap to me. coolant wasn't coming out the overflow pipe afterall. it was coming from the rad cap that wasn't on properly.
Darwin award for me :/ :D
cap on properly and bike seems fine again but will double check tomorrow and buy more coolant for the garage as stock :)
thanks for the help.

Re: Coolant overflowing

Posted: Mon Jun 24, 2013 10:29 am
by DJTEMEKA
Just realised the missus doesn't use her regular forum name here. It's PoisonIvy on this forum :)
Not heard from her today yet after riding the bike into work so no news is good news :)