Coolant Leak

[Rikugun]

Since getting my Vision on the road last spring I've only put several thousand miles on it. In that time there have been a few times where I've noticed coolant pooled in the slight cavity around the coolant tubes where they leave the cover. I don't recall ever having to add to the reservoir. Having other more pressing issues I never investigated as it never left so much as a puddle. Of course eventually I knew I'd get to it... :P

Various problems made for an early end to the Vision's season and she's sat on the bench ever since with never a leak. Today I went into the garage and saw this:
 
No leak yesterday BTW. Enough leaked out to run down the motor, drip off the header pipe and make a small puddle. Total volume I'd guess to be 50ml.

The only thing unusual about today is the temp - reached 60F, but it seems we've had a few warmer days in the last couple of weeks.

Do you think it's as simple as replacing the o-rings, or much more sinister  :o forces at work? Why leak there and not the top of the tubes as well? The tubes can be moved by hand which I guess is normal (?) since there is nothing securing them other than o-rings top and bottom.

Any thoughts?

[AdvRich]

Awe it's just weeping tears of green in anticipation of Spring..... ;D

They did this new in '82 that I remember seeing in the shop. New O-rings sorted it. Thought there may be a better fit or upgrade. I can add that much of my .02¢

[YellowJacket!]

Usually an easy fix.  remove and clean the ends of the tubes and replace the o-rings.  You can also get extra rings to slide down into the space above the thermostat housing where the chrome tubes fit in.  Acts as a secondary o-ring and keeps the gap clean.

David

[Night Vision]

you getting ready for St Patricks Day?  ;D

not a great design
try smearing some red rtv on new #12 orings, make sure the surfaces are clean and dry, and hope for the best.

[QBS]

Carefully remove the tubes.  They can be kinked, ham fistedness is not the way to go.  Dry and clean the tube receptor areas very well.  Lightly grease the receptor areas.  Insert the tubes, with new "O" rings in place, into the receptor areas.  Make sure that the rings end up well positioned down into the receptor areas.  Declare victory.

IMHO, no type of sealent is needed and I definitely recommend against it. Using a sealent product won't cause damage, but it will make a mess and not produce a better seal.

[Lucky]

and another way to do it:
Drain the coolant from the pump into a catch basin.

unbolt the waterpump housing.  it has 2 o-rings so don't worry about replacing a gasket. don't lose the smaller one at the top.  since it's off, inspect the waterpump & thermostat.

remove the tubes. clean out the 4 holes the tubes fit into. i used a round brush on a dremil to get it very clean.

fit new orings & install.  a dab of plumers grease, or WD-40 makes it easier.  reasemble pump, fill with coolant, start the bike & allow it to warm up.  bleed the air out with the bolt on the union under the tank & Done!

[Rikugun]

Awe it's just weeping tears of green in anticipation of Spring

I should have thought of that but instead got mad and yelled at her for making a mess. I turned out the lights and shut the garage door figuring she'd have all night to reflect on her error and work things out on her own. I was wrong...  :o

Now she won't even talk to me!!  :o  :(  :'(  lol

Lucky, thanks for the detailed how-to and Dremel tip.  I'd read the section in the manual and would not have attempted without removing the cover. Is that what QBS referred to by "They can be kinked"?

Also, I'm not a big fan of grease and RTV (of any color) where they don't belong. Provided everything is clean and burr free, wouldn't coolant be a more suitable assembly lube?

YJ, hadn't thought of the extra o-rings. Might just try that to help keep out debris.

[Lucky]

i'd do the dremil if there is a lot of corrosion.  Kittys was bad...  otherwise just clean it up.  if you do end up using a dremil you might end up going oversize on the oring if the surface is not smooth or ends up bigger. if you can find the right size slightly oversize...

RTV should be used if warrented.  the bikes are 30 years old after all...

[Rikugun]

Point taken. Thanks for all the suggestions guys.  ;)

[Kenny]

  I have used a method similar to Yellow Jacket's for years and have not had any more leaks & it has worked every time Plus it seems to center the tubes in the housing. Once again give both surfaces that the "O" ring touches a good look over and must be smooth to get a good seal.  ;)  
  Geez is it ever wet in Louisville Kentucky!
                        Cheers Ken S.

[QBS]

It is possible (if done with care) to remove the tubes without disturbing the water pump housing.  Care must be taken during the procedure to not subject the tubes to bending stresses, lest they become kinked.

[Tiger]

 :) I would advise that you remove the hose from the thermostat housing, (drain the old coolant in to a bowl/bucket, etc), remove the thermostat housing screws, pull the thermostat housing and chrome coolant tubes away from the engine.

Please Note: The two chrome coolant tubes are of a different length!! Make sure you put them back correctly the first time... :P
   
Remove the four old 'O' rings.
Clean up the chrome coolant tubes...(A good time to polish them!!).
Clean out the four 'ports' where the coolant tubes are located completely. ( I use a short, round (barrel shape) wire brush, with a handle, for this...It has brass bristles and is for cleaning truck battery terminals).
Use a wee smear of Vaseline on the four new 'O' rings and insert them on to the nice and shiny chrome coolant tubes.
Insert the two chrome coolant tubes back in to the thermostat housing, which you thoroughly cleaned...making sure that the thermostat housing 'O' ring is in place to (use a wee smear of Vaseline on this 'O' ring to).
Offer up the thermostat housing and chrome coolant tubes to the engine and install the soc head cap screws...tighten up.
Install the black rubber coolant hose to the thermostat housing and tighten the hose clamp.
Remove the rad' plastic cover and rad cap (if you haven't already done so) and slowly refill with fresh coolant mix.
Once filled...and this is my preference...start up the Vision WITH THE RAD CAP REMOVED!!!...and let her get up to working temp...during this time you will note air bubbles in the rad. When these subside, switch off the Vision and let her cool off.
Check coolant level is good, install rad cap and plastic rad cowl and take her for a spin.........VOILA!!!

8) .......TIGER....... 8)

[Rikugun]

Geez is it ever wet in Louisville Kentucky!

Here too!  I guess we got it after it was done with you. Woke up to a flooded basement this AM. Float on the sump pump apparently got stuck.   >:(  :(

[Night Vision]

you can unstick a sticky float by whacking it with a hammer  ;) sorry, out of context

[jasonm.]

LASTLY I do NOT recommend the Yamaha o-rings. Basically if you have used sandpaper or something else to "clean" the surface. I cleaned mine  w/#600 then #1000 . Now the hole is bigger. Yes, slightly. The stock o-rings will not make up for the new size and shape of the hole. I got #13 o-rings from the local hardware store. They fit just tight enough to make up for the corrosion that you have "cleaned up". Yes use a dab of waterproof grease. 

[Rikugun]

It seems this joint may have been marginal right from the factory so I can see where using the OEM o-ring wouldn't guarantee a successful repair. Enlarging the bore through corrosion removal would certainly not help matters! All good info.

[Rikugun]

Found a nice slightly larger O-ring which seems to be working well. Thanks for all the advice!  :)