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I took my kdx out for a ride the weekend before last and one of the clips that held the coolant hoses on cam undone and I lost quite a bit of coolant. After that we tightened up and refilled the radiator. For some reason the bike was losing coolant and constantly needing toppong up throughout the course of the day.

To make sure when we got the bike home we bled the radiator with 50/50 antifreeze and water through all of the bleed screws. We also changed the oil to make sur there wasan't any water in their which their wasn't it, it looked like pure oil.

Now after that we took my bike out for a ride last weekend and throughout a 3-4 hour ride and I went through a whole pump bottle of coolant (around 750mL). The thought of im burning it has crossed my mind but the bike hasn't lost any performance. Also not sure if it matters but my radiator cap when undoing it seems to have pressure and I cant see any fluid boiling out the top of it when riding.

Anyone got any ideas thanks.

You'd be able to smell the antifreeze pretty easy if'n you were burnin it (smells sweet)

Mine did for a long time and I did not notice any loss in power

You say you are adding fluid during a days ride. I'm guessing you are adding it to the overflow tank. If so, they are notorious for loosing fluid as the bike is being bounced around down the trail. Always check the fluid in the radiator by looking under the radiator cap. Just don't do it hot!! If you aren't loosing fluid from the radiator, just from the overflow tank then there really isn't a problem, just a learning curve on how the overflow tank isn't very good. However, if fluid is being drained from the radiator as evidenced by a loss of coolant from the radiator after checking by removing the cap after it cools off, then I'd say your cap isn't holding pressure and needs replacement. A few ounces of coolant is about all you should be able to add to a cold radiator through the cap opening. Once warmed up, the cap will vent about 2 or 3 oz into the overflow tank, the tank will promptly spill those contents out the overflow tube in a tip over a through bouncing.

uh yeah, what he said

overflow tank is about useless

My bike just smells like 2 stroke to me I dont think I can smell burning antifreeze but then I could be wrong.

If a fill the radiator full a small amount of coolant does overflow but it overflows onto the floor. I do not think I have an overflow tank, I think it was taken off by the previous owner. Throughout the 4 hour ride I lost a total of 750mL of coolant, can you actually lose this much from the radiator cap not having enough pressure. I am opening the cap slowly after about 1 min of the bike stopping to check the coolant and I top it up when it is anywhere below the fins.

Could only be a few things... a clog, a bad pump or a bad cap.

Why is it bad to open why it is hot?

What would make me lose the most because 750mL is 3/4 of the cooling system?

My overflow tank has always lost *some* during a ride. Lately it has been loosing all or nearly all.

I became concerned so when it cooled down I pulled off the 1.1 rad cap and found that the fluid was up to the top just the way I left it.

I put two and two together -- and then checked this thread for back up.

Rick

GhostRider wrote:Why is it bad to open why it is hot?

What would make me lose the most because 750mL is 3/4 of the cooling system?

It is bad to open a hot radiator cap because it SHOULD be under high pressure. If you open the cap when the bike is hot, radiator fluid should spray out under pressure and will most likely burn the snot out of you. If you can open your cap when the bike is hot, then it isn't working right and is allowing expanded coolant to overflow out. It's always a good idea to change your cap at least once a year. They are cheaper at an auto parts store than a kawasaki dealer.

I don't understand your second question.

The cap I can undo when hot but I have to open really slowly, I havent replaced the cap in the 2 years of owning the bike but it does feel like it has pressure behind it.

Im just saying in 3-4 hours isn't 750mL alot to lose due to a cap. Is the cap likely to be the problem? or is there something else that would more likely make me lose that much fluid? thanks.

I would change the cap or if you know a mechanic with a pressure tester, time to talk to them.

Check the color of your gear oil too. If its milky, coolant is mixing with gear oil.

The coolant must be going somewhere. If it's not coming out the vent, (bad cap), then it's getting out somewhere else. A leak in a hose, at a clamp, past a seal and into the motor, etc. Yes, that is way too much fluid to lose in a single ride. I could go a full year without losing a drop before changing it out at the service interval.

You stated there was some pressure behind the cap when opened hot. There should be quite a bit of pressure. Enough that if you didn't use a rag to protect your hand, it would get a pretty good steam burn. I think, for the price a a few dollars at the local auto parts store, it would be a good idea to change the cap at this time..

Thanks everyone I think I will go with 1.6 rad cap and pressure test the whole system.

Your bike should have an overflow resevoir behind the left side pannel, correct? You stated that it might have been removed? What about the hoses that ran to it? Are they plugged? If not, when the bike gets hot, and pressure builds up in the rad, the anti-freeze could be running out of one of those ''un-capped" hoses. Just a thought.

I think that could just be the problem, I know it does leak out of the overflow alot, but isnt that normal if you top the radiator right up to the top, how many tubes went to the previous bottle. Thanks again

I'm not sure about how many tubes. Mine doesn't have an overflow. But I'm pretty sure yours did. Hopefully someone with a similar model can chime in and help out. My thinking was, A- cant see a leak out of the rad, B-don't see it in the tranny fluid, C-its losing a ton of fluid, and you cant find it. Its gotta be coming out somewhere that your not seeing, hence a missed hose unhooked. Or it is boiling it out, and you don't recognize the smell. You should smell it though.

A crack in a hose that leaks when the pressure builds up perhaps?

Maybe

Rez on the 'H' model is under the right rad shroud...

Some prefer taking the rez off. I don't. During normal riding the bike WILL get hot, dump some coolant into the rez, but as soon as the bike cools (relatively) off, the coolant will get sucked back into the system.

Two hoses to the rez. The long one (to about the bottom of the tank) goes to the rad, the shorter one is the overflow from the REZ..

Putting coolant IN the rez is pretty much a waste of time. Over a day's ride, it WILL get bounced/sloshed/spilled out. It's the short cycle of overheat/blow coolant/cool/suck coolant that the rez is good for.

I ran without the rez bottle for awhile..was low on coolant after every ride.

Rez is reservior..the bottle.

A new cap is a good place to start.

IF..'The cap I can undo when hot but I have to open really slowly..' means the hot bike does NOT spit, sputter and spew all over the place in the process...it's leaking internally. Replacing the head gasket would be a good place to start on that problem.