1st boil-over.

14 replies to this topic
  • johnny6speed

Posted June 11, 2011 - 05:36 AM


My 09 has 15.5 hours on in now, and yesterday, I was pushing my way through "the bush" behind my house for about 30 minutes to get to an old porcupine tree and the bike started pissing out steam from the front of the case, right in front of the OE glide plate.

It did this for about 4-5 (mississippi's) after I shut it down. I let it cool for about 5 mins while walking it back out the way I came. It fired up on the 2nd kick and I lugged it home and put it in the garage asap. After it cooled down I checked the coolant level, it was down 1/4-1/2 inch from the recommended level. Should I top it off with distilled water? Or 50-50 coolant? Or neither?

Generally speaking what is the recommended procedure in the future should this happen again?

  • DEMI

Posted June 11, 2011 - 05:44 AM


Distilled water will be fine. As you know, these bikes need air thru the rads to help cool... you could always go to a 1.4 to 1.8 psi rad cap, along with a 60/40 water/coolant mix.

  • MrBlahh

Posted June 11, 2011 - 05:47 AM


2 caps of water weter helped my wr quite a bit when I kid chase

  • YZPaGuy

Posted June 11, 2011 - 11:43 AM


Use a good quality coolant. You can make your own. There are some threads on here is you do a search. I tried all water and water wetter in my 08 YZ450F but it made the bike boil over too fast. It will lower the temp of the bike but the boil over temp of the fluid comes way down. I use Honda coolant and haven't had any problems whether riding with the kids or tight stuff. I do keep myself awhere of the potential though.

  • Yamiryder

Posted June 11, 2011 - 05:16 PM


I think I saw that Lucas makes a radiator fluid additive that is to lower the temp. Has anyone heard of this or used it?

  • primerib108

Posted June 12, 2011 - 05:11 AM


I use engine ice and it has worked well for me. I mostly bike tight woods trails....no boil overs.

  • grayracer513

Posted June 12, 2011 - 01:28 PM


Top off with a 50/50 ethylene glycol coolant/water mix (distilled water preferred), or a premixed EG based coolant (green stuff). Reason being that assuming your bike currently has the original fill in it, it's EG, and you should not mix propylene glycol with it. Straight distilled water is OK, but you'll lower the boiling point if you do that.

The place where you saw the steam come from was where the end of the overflow hose is located.

Two things you can do to get a little higher boiling point is to use the Red Line Water Wetter previously mentioned, and a PG based coolant. You can use a good brand of automotive PG, or a premixed product like Engine Ice. Doing these things will hold off boil over to about 10-15 degrees higher.

Something that really works if you insist on doing a lot of that sort of thing is a small battery operated fan on at least one radiator.

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  • Yamiryder

Posted June 12, 2011 - 04:05 PM


I have engine ice in my bike...where do you get water wetter?

  • MrBlahh

Posted June 12, 2011 - 04:49 PM


I ordered it online, I only added 2 capfuls of it into a 50/50 antifreeze mix, and it made a big difference

  • beezer

Posted June 12, 2011 - 05:05 PM


I wouldn't worry about it. It's a common occurence with a YZ in the woods.

Why would you want to get to an old porcupine tree?

What is a porcupine tree?

  • Yamiryder

Posted June 12, 2011 - 05:53 PM


I ordered it online, I only added 2 capfuls of it into a 50/50 antifreeze mix, and it made a big difference

Would it work in engine ice?

  • grayracer513

Posted June 12, 2011 - 06:56 PM


Water wetter is a surfactant. Its function is to improve the thermal transfer between the coolant and the metal of the engine and radiators by breaking the surface tension of water much as soaps and detergents do. It is less necessary when using a coolant mix than with straight water, but yes, it still helps, and it will work.

  • brentn

Posted June 12, 2011 - 08:30 PM


We really should make a sticky thread at the top for posts like these. People aren't checking the FAQ enough, we get this question almost once a day it seems!
Even a shortcut link titled "boiling over your coolant? Click here" and then link it directly to the FAQ or something.

  • johnny6speed

Posted June 13, 2011 - 04:23 AM


Correct me if I'm wrong. I quickly perused the FAQ and didn't see any links for this type of situation. Though, I sometimes have trouble finding things right in front of my face! :ride:

  • Hurricane

Posted June 15, 2011 - 10:26 AM


Running Amsoil antifreeze, very similar to Engine Ice, and have not had any boil overs while brush busting trail. Good stuff. I've also hear that Evans is really good stuff but I have no experience with it.

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