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5valve

cooling liquid dissappearing

22 posts in this topic

I have this problem for quite some time now on my 400 and it doesnt give me such a pain in the a$$, but nevertheless, if anyone should know what tut put the blame on, would be nice to know

at each ride, cooling level drops from max level to about third or half way down to the min level and it only does it in the owerflow bottle

the radiator level is always filled to the max, even though I did 2 rides with empty owerflow bottle...radiators stay untouched

no whitish engine oil, no obvious leakage :)

when bike overheated once, fluid nicely expanded into the bottle, could hear it, but not see it because of the mud fassade all over

any ideas

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Mine appears to do the same thing , always has.When it starts to drop in the radiator i will go looking for answers.I always put it down to it finding it's own level.

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I agree with it finding its own level, as long as its not dropping the level in the radiators i wouldn't worry about it, my car is the smae way, no matter how much i put in the overflow it just dumps it out some where along the way, but the level in the rad never drops

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I'm a little late on posting about this, but I have the EXACT same problem. My 98 WR400 doesn't even have the reserve bottle in the back, the previous owner took it off to lighten it up (IDIOT). Even with the reserve, these bikes get overheated very quickly. Once you have the bike warmed up, NEVER let it sit idling for more than 60 seconds. They need air flow through the radiator to keep them cool. If you stop, the coolant starts to boil! Mine used to boil over all the time cuz I didn't know. Now if I stop on a trail for more than a few seconds, I'll kill the bike and restart it when I'm ready to take off. It's a minor pain in the a$$, but the alternative is much worse!

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Hey you guys ever here of evaporation? Yeah this happens to liquid when the temperature gets a little to hot or dry in an unsealed system. You ever put a pan on the stove and boil the water away. DUH !! same principle. It's is amazing. How did you guys even learn how to walk?

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Ever heard of not being a condescening knob-end to people who ask a legitamate question?

It is supposed to overflow into the appropriately named 'overflow bottle'. So something isn't quite right Dr. Science.

What type of coolant are you guys using?

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Mousemeat you are a riot!

You really shouldn't be losing any coolant. The level on my bike stays the same. If it dosn't it the coolant has to be going some where.

It isn't evaporating the system is basicaly closed. I wonder if your headgasket is leaking a bit.

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Too Far, :)

Maybe you don't understand one of the cool features of this website...a person with little skills and/or knowledge can ask a question without feeling like a tool, then people can drop their input to help a brutha out. Helping answer the question will go a lot farther than being a smarta$$.

Back to the thread...

I mentioned my bike no longer has the resevoir under the left rear fender. Where does the tube connecting it to the radiator enter the radiator(top, bottom,left or right side)? I'd like to be sure the previous owner capped that off when he removed the resevoir.

Remember out there, no question is stupid if you truly don't know the answer. And why take a chance at screwing up something when you can find the answer in here. This is a great place to pick someone's brain! :)

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My bike has done the same thing on occasion. I just add more fluid to the overflow when cold of course to ensure the correct level.

I run water wetter or the other one.... the name escapes me but its pink

Fryboy

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Ever heard of not being a condescening knob-end to people who ask a legitamate question?

It is supposed to overflow into the appropriately named 'overflow bottle'. So something isn't quite right Dr. Science.

What type of coolant are you guys using?

Mousemeat maybe you should read what they posted before looking like an idiot. He says it only loses coolant in the overflow bottle. ( perfectly normal )

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Too Far, :)

Maybe you don't understand one of the cool features of this website...a person with little skills and/or knowledge can ask a question without feeling like a tool, then people can drop their input to help a brutha out. Helping answer the question will go a lot farther than being a smarta$$.

Back to the thread...

I mentioned my bike no longer has the resevoir under the left rear fender. Where does the tube connecting it to the radiator enter the radiator(top, bottom,left or right side)? I'd like to be sure the previous owner capped that off when he removed the resevoir.

Remember out there, no question is stupid if you truly don't know the answer. And why take a chance at screwing up something when you can find the answer in here. This is a great place to pick someone's brain! :)

Kevin1209 I was not responding to you!! I was responding to the original poster who has a overflow bottle and this is where the fluid is disappearing from. The overflow bottle is not a sealed system.

As for your bike not having a bottle and knowing it was removed And have not replaced it well all I can say is Good luck !!

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All snide comments and petty bickering aside, the overflow reservoir is there to accept extra fluid in case of boil-over AND to replenish the radiator if the total coolant in the "sealed" system diminishes. If coolant leaves the "sealed" system (radiator, hoses, and engine) somehow, the coolant in the reservoir replaces it. So, of course, if you have a leak, it will show up in the overflow reservoir first. When that is completely empty and can no longer supply extra coolant to the radiator and "sealed" system, then and only then will the radiator begin to show a low coolant level.

Your overflow reservoir is doing its job. HOWEVER, your "sealed" system is not. Coolant doesn't simply evaporate in a short time period. You either have a leak in a hose or connection, OR you have a bad head gasket. One third possibility that is extremely rare is a bad casting at the water jacket. For our purposes, we'll ignore that.

I would first check all connections to be sure they are not leaking under increased temperature or pressure, which you would create when you ride the bike under normal conditions. Next, if you have no coolant in your oil, I'd check the head gasket. Coolant may be leaking into the cylinder, getting vaporized, and blown out the exhaust.

If you detect a drop in coolant level within about 500 miles, you likely have a leak in the system somewhere. If you have to top off every ride, you have a big problem. I have roughly 5,000 miles on my '00 WR400F, and have only topped the system off two or three times (with one complete coolant change about 1-1/2 years ago). It should be that tight.

Additionally, if your bike overheats every time you stop and idle for a few moments, or ride in tight technical conditions, you likely have very lean jetting. See the jetting forum if you haven't checked your jetting lately, and get JD's jetting guide. These bikes have a very adequate cooling system when things are working as designed. It's only when maintenance or tuning are necessary that you see problems like this.

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All snide comments and petty bickering aside, the overflow reservoir is there to accept extra fluid in case of boil-over AND to replenish the radiator if the total coolant in the "sealed" system diminishes. If coolant leaves the "sealed" system (radiator, hoses, and engine) somehow, the coolant in the reservoir replaces it. So, of course, if you have a leak, it will show up in the overflow reservoir first. When that is completely empty and can no longer supply extra coolant to the radiator and "sealed" system, then and only then will the radiator begin to show a low coolant level.

Your overflow reservoir is doing its job. HOWEVER, your "sealed" system is not. Coolant doesn't simply evaporate in a short time period. You either have a leak in a hose or connection, OR you have a bad head gasket. One third possibility that is extremely rare is a bad casting at the water jacket. For our purposes, we'll ignore that.

I would first check all connections to be sure they are not leaking under increased temperature or pressure, which you would create when you ride the bike under normal conditions. Next, if you have no coolant in your oil, I'd check the head gasket. Coolant may be leaking into the cylinder, getting vaporized, and blown out the exhaust.

If you detect a drop in coolant level within about 500 miles, you likely have a leak in the system somewhere. If you have to top off every ride, you have a big problem. I have roughly 5,000 miles on my '00 WR400F, and have only topped the system off two or three times (with one complete coolant change about 1-1/2 years ago). It should be that tight.

Additionally, if your bike overheats every time you stop and idle for a few moments, or ride in tight technical conditions, you likely have very lean jetting. See the jetting forum if you haven't checked your jetting lately, and get JD's jetting guide. These bikes have a very adequate cooling system when things are working as designed. It's only when maintenance or tuning are necessary that you see problems like this.

Very well put, Dan.

If you are losing coolant regularly from the reservoir, there is likely a leak somewhere. Either internal or external, you should do some checking to find out where.

My 426 has 1200 miles. I have never topped off the coolant in between flushes.

Check all your connections and make sure your engine oil is not milky or foggy looking.

:)

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Here are a couple of things to check if you think you may have a head gasket leak or crack in the head.

Pull your plug and carefully inspect the color - if it is abnormally yellowish-light colored (not the normal healthy tan color), that is a bad sign. Antifreeze will leave deposits on your plug over time.

This next test may sound weird, but take off your radiator cap and stick your shnoz down in there and take a whiff. If you smell exhaust , that's a leak. A leak path that allows coolant to be sucked into the cylinder on the intake stroke will also usually allow high pressure exhaust gases to be blown into your cooling system on the power stroke - hence the exhaust smell. The exhaust leakage can disrupt your coolant circulation to the radiator (like vapor lock in a fuel line) and cause boiling and overheating. If your leak is small, the signs can be very subtle and the bike will still appear to run fine most of the time. Carefully monitor you coolant usage and if you do have a leak, it will slowly drain your cooling system over time - first your overflow bottle will go dry and then your radiator level will drop as well. If your radiator level holds constant all the time, then your probably ok. Like Dan said, first check for obvious hose connection leaks and then check your jetting and make sure your not running too lean - these are the usual suspects.

Good luck

:)

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at each ride, cooling level drops from max level to about third or half way down to the min level and it only does it in the owerflow bottle

the radiator level is always filled to the max, even though I did 2 rides with empty owerflow bottle...radiators stay untouched

no whitish engine oil, no obvious leakage :)

when bike overheated once, fluid nicely expanded into the bottle, could hear it, but not see it because of the mud fassade all over

any ideas

my bike can idle for long periods of time, never to overheat...it only does it in the snow hillclimbing

paxnnc.jpg

, when speed is close to zero and 2nd or 3rd gear rips for longer time

I too am thinking of head leakage, but I have past experience with this, and if this was the case, the radiator coolant would dissappear rather quickly, while not really affecting the bike performance

head gasket is new (for some time now :))

there is no other reasonable explanation for this, except for already suggested ones, wich I am aware of

thnx

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if you still remember this thread..found the problem and it is pissing water pump, obviously common stuff

on previous occasions I didnt notice the leak, but on the last ride the cold bike pissed a bit, than stopped, probably because of heat expanding the o rings

at least I think Im good for now, not yet digged into it but expect it soon

stil curios why the radiator level didnt lower, thats a q for the twilight zone :)

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