leak in coolant reservoir...possible to fix?

10 replies to this topic
  • gregk

Posted September 13, 2007 - 09:47 AM


Hi all,

since a few ride I have noticed the level in my coolant reservoir dropping quite fast to just under the low level mark, and then going down much more slowly....I was quite worried as I did not notice obvious leaks (coolant on the floor of my garage), and was fearing a faulty head gasket or worse....

Luckily (sort of), it is nothing serious: today I had a short commute trip to office (road only) and overfilled a little bit my reservoir before going. I identified a leak in the coolant reservoir itself, which has escaped me before because it is at the high level and was hidden by the mud during my last offroad rides...when I cleaned the bike the coolant was already under the leak point so I saw nothing....

There is no hole, rather the reservoir has split along its central welding line (it seems made of symmetric plastic parts (left and right), welded...maybe a faulty plastic welding...or a hair crack due to vibration?). This is invisible under normal circumpstances, and the leak is very small, almost non-existent when the bike is not running....but I guess it is more significant under vibration and large if I compress the reservoir manually (I can see the 2 part separating and coolant going out...).

Do you think it is possible to fix this, rewelding the reservoir using heat? (glue seems a bad idea, I guess it is polyethylene and gluing this plastic is almost impossible)...

Or do I just have to buy new a new one (I expect to be out of luck finding that stock...bad luck for the WE :thumbsup: ...but I guess it is not expensive)

BTW I have a WR450 2004, but I guess the coolant reservoir is very similar on all WR...

Thanks for any idea dealing with this,



  • dustinw

Posted September 13, 2007 - 10:49 AM


just melt it closed with whatever you have handy. Shouldn't be a problem.

  • Derek00

Posted September 13, 2007 - 11:14 AM


Some kayak shops do "plastic welding" to repair ABS boats. You may be able to find a kit on the internet.

  • byggd

Posted September 14, 2007 - 10:31 AM


You should be able to find something like this in Belgium.

  • gregk

Posted September 14, 2007 - 10:43 AM


wow, thanks but I think it is a little bit of overkill: the reservoir is not under pressure, so I agree with previous poster that it should not be too hard to fix it: today i melted it with a soldering iron, and added a bit of silicone afterward for good measure....I hope it will be strong enough, tomorrow or sunday I will test it some...Except if my rear tire hit it on a jump reception, I expect it to be ok....and as I am not good enough to jump as high as I would, it should not be a problem :ride: :thumbsup:

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  • gregk

Posted September 19, 2007 - 09:52 AM


I tested my quick fix (welding the reservoir with a soldering iron, and adding some silicone for good measure...). It seems to be ok, no real stress on this part so I guess any fix having a minimal resistance and water-tight is enough.

If other have this problem, you know that 5 minutes and a soldering iron is enough, no need to buy new part :thumbsup:.


  • Frank_z28

Posted September 19, 2007 - 09:58 AM


epoxy glue maybe help seal it too

  • drtbk4ever

Posted September 19, 2007 - 04:47 PM


Duct tape?

  • gregk

Posted September 20, 2007 - 12:15 AM


Duct tape?

Lol...I love duct tape as much as anybody, but here it may be just a little too weak and not water tight enough...On the other hand, everybody know it is perfect for fixing a split frame or swingarm ...:thumbsup:

  • snowman02

Posted September 21, 2007 - 09:56 AM


Parts house's have this two part epoxy putty similar to JB Weld. I had a hole in my gas tank on my truck and used this to seal it. it worked wonderful. 4 years later i sold the truck and it was still sealed. It is in a plastic tube and it grey and black.

  • jandmsuburban7

Posted September 22, 2007 - 11:03 AM


Hey, glueing is not a good idea - it wont hold. 100% silicone might work. Best is to melt it (off the bike and clean it inside and out first). I dont think you need to buy a welding kit. You can take a hammer and flatten out a nail and bend it a little like a miniature spatula or use a standard screw driver and bend it a little. The idea is to get the tip of the nail or other metal hot and move the hot metal in small circles over the part that has the crack in it and smear the melted plastic over itself and that should fix your problem. Dont get the metal too hot though or you will make a whole in the plastic which will be harder to repair and then you may need to use some reinforcement plastic (i.e. milk carton?? Dont know for sure if the two plastics are the same?? Good luck, Jason


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