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boer

Boiling coolant

7 posts in this topic

I noticed on my last ride that the engine was getting very hot due to the ambient temp and heavy engine load and low speed riding in the desert. The radiator cap was making hissing sounds and the coolant was boiling over to and finally out of the expansion tank.

Do any of you guys experience this to. Is it common? Can the engines take it? What is the best thing to do if it happens, idle, ride or stop engine and let cool?

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I noticed on my last ride that the engine was getting very hot due to the ambient temp and heavy engine load and low speed riding in the desert. The radiator cap was making hissing sounds and the coolant was boiling over to and finally out of the expansion tank.

Do any of you guys experience this to. Is it common? Can the engines take it? What is the best thing to do if it happens, idle, ride or stop engine and let cool?

Stop engine and let it cool unless you can wick it up and get some air blowing across the rads......... Running a better coolant such as EVANS or ENGINE ICE will help. You can go as far as getting a set of fluidyne rads but it will still happen. The bikes get hot especially if they are set up lean at all. The WR comes with a coolant resevoir because it is designed to ride tight single track that can produce low speeds and poor heat exchange in the rads.

Is it bad for the motor? In big doses yes but intermittenly overheating because you can't go fast enough to remove the heat in the rads is not real bad......... But one should shut it down and let it cool off as necessary.

The 2COOL oil additive is supposed to reduce engine temps too :ride:

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Boer,

This has happened on my 06 WR450 a few times. Especially when the trails get slow and nasty.....I normally speed up to get things cooled down. I recently changed the coolant in my bike and on the same trails it doesn't boil over as bad. I believe I went with a Prestone 50/50 blend that I picked up at the local auto parts store. It met all of Yamaha 's recommendations and defiantly cools better than what was in it.

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It isn't necessarily boiling, but exceeding the cap pressure do to increased temperatures, thus over flowing in to the catch tank. Water dose not compress at all, and expands when heated. When it warms up, it has to have a place to go, or something will give(even steel).

Mine hasn't overflowed yet, but when it does I'm not gonna get worried as long as long as I'm moving along.

Theres still plenty of coolant in your motor to keep things in check. :ride::banana:

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I went with Engine Ice and it seems a lot better. I'm also trying to be more active in having air move through the rad(going faster). If I have to do a slow tech section that lasts for a while I cool off both the bike and myself after. I never just let my bike sit and idle if I stop to talk about trails with my buddies. I just shut it off when I stop. Let's me hear mother nature too and my bike likes the rest.

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On my 06 wr450 I experienced something alittle different my hose melted that runs off the cap on the reservoir and supposedly caused a vacumm then when it opened back up from more melting. Before I knew it it threw all of the coolant out of the reservoir. This is what I was told from the Yamaha dealer tech.Temps during the event was middle 90's here in Phoenix.

The tech told me to disconnect the top hose and it should prevent this problem from occuring again, additionally I did have the idle too high so when I stopped riding those few times it must of cherryed the exhaust eventually melted the hose which I could see. This hose is right behind the first exhaust connection coming from the head.

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