Cooling issue...

[braaap]

Here goes.

about a month ago I joined up here with intentions of buying a 250. well. I did. and it is having a cooling issue that since mid april I have yet to figure out.

replaced thermostat and radiator cap.

resevoir boiling up around highway speeds. 50mph or below the bikes temp stays stable, it even stays stable at the highway speeds, but the coolant resevoir fills up and starts to piss out.

opened the radiator cap about ten minutes ago, turn the bike on, no coolant is moving at the radiator cap at all. am i just being cheap and not wanting to replace the water pump?

last night I opened up the water pump housing, the pump moves when ticking over the bike. no, i didnt run it, tapped the starter and saw the thing move. did it a few times, had some play, but it moved. im talking slight play, maybe a quarter inch clock and counter clockwise.

refilled the system, and it seemed to run better up until higher rpm, did the same thing. We did most of our testing at a stand still, the fan comes on better with completely new coolant, but even so, still boils into the reservoir and leaks out the overflow tube. stays pretty stable at idle actually. and the thermostat is new, confirmed working when we boiled the old one (which worked btw...) and threw the new one into the boiling water.

im thinking water pump, but dont want to come to terms with my new found belief lol...

I know you guys can help, love this little bike and glad I own another one. never should have sold my first ninja 250...this things so nice to rip around town. if only it cooled right!

[quarterliter]

At high RPMS without air moving past the radiator, I would expect it to overheat. Do you have anything blocking the radiator?

[braaap]

no sir.

it also did this in motion at 65mph around 8k rpm for about 2.5 miles. it slowly creeped to the top of the reservoir and leaked out onto the tire.

kept the side covers off so i could watch the tank as i ride. unsafe? sure. only way to see if it does it at speed.

[csmith12]

How are you burping the air out of the system? If yours is anything like mine, you have to have patience and be diligent to get ALL the air out.

[jkv45]

I'm thinking the radiator cap is bad.

Is the level in the radiator up to the top when you open it after running and cooling off?

What does the temp gauge read when it happens?

[quarterliter]

The level will rise as it heats up. What is level like in the reservoir. Between the L and H marks I would assume?

[csmith12]

Oh! Gratz on your purchase. Time to update your profile so we know what ya got, a pic wouldn't hurt either.

[braaap]

Originally Posted by csmith12

How are you burping the air out of the system? If yours is anything like mine, you have to have patience and be diligent to get ALL the air out.

How are you burping the air out? are you rocking the bike side to side at all?

i was filling the coolant up in the radiator fill spot, taking my time, than filled up the reservoir. I did not intentionally burp anything.

[braaap]

Originally Posted by quarterliter

The level will rise as it heats up. What is level like in the reservoir. Between the L and H marks I would assume?

the reservoir now is at the L mark. but i put it back to that point as the bike heats up and cools down.

[csmith12]

Originally Posted by jkv45

I'm thinking the radiator cap is bad.

In OP, a new one was purchased. New one bad? Maybe, but wouldn't suspect it right away.

[braaap]

Originally Posted by jkv45

I'm thinking the radiator cap is bad.

just replaced with new oem product.

BUT where the cap goes on, down in the hole where the tubing is is pretty corroded and gummed up. I have scraped it off as best as possible, and the seal at the top is perfect.

[braaap]

Originally Posted by csmith12

In OP, a new one was purchased. New one bad? Maybe, but wouldn't suspect it right away.

same, I could have it tested i suppose but idk if it would be worth it. its oem new.

[jkv45]

Originally Posted by csmith12

In OP, a new one was purchased. New one bad? Maybe, but wouldn't suspect it right away.

Hmmm, missed that...

Wrong cap maybe?

[quarterliter]

Originally Posted by braaap

just replaced with new oem product.

BUT where the cap goes on, down in the hole where the tubing is is pretty corroded and gummed up. I have scraped it off as best as possible, and the seal at the top is perfect.

Could passages in the radiator be plugged from the corrosion and gummyness?

[braaap]

Originally Posted by quarterliter

Could passages in the radiator be plugged from the corrosion and gummyness?

potentially, when we disassembled the water pump yesterday we left the drain plug off and poured new coolant through the radiator cap.

it came out just about as fast as it went in.

[jkv45]

Originally Posted by braaap

just replaced with new oem product.

BUT where the cap goes on, down in the hole where the tubing is is pretty corroded and gummed up. I have scraped it off as best as possible, and the seal at the top is perfect.

It may not be making a seal and allowing the expanding coolant to go to the overflow bottle instead of holding pressure.

[csmith12]

Originally Posted by braaap

I did not intentionally burp anything.

Let's start there. I simply run the bike with the cap off until the thermostat opens and all the air bubble stop coming out. The occasional light rev at the end just to be sure.

See here too for more info and in similar threads at the bottom of the page.

Another oddity I have seen in the past is that the radiator neck lip (where the cap goes on) had a dimple in it. Causing the old and new radiator cap not seat properly. The cap must make a good seal.

[braaap]

Originally Posted by csmith12

Let's start there. I simply run the bike with the cap off until the thermostat opens and all the air bubble stop coming out. The occasional light rev at the end just to be sure.

See here too for more info.

Another oddity I have seen in the past is that the radiator neck lip (where the cap goes on) had a dimple in it. Causing the old and new radiator cap not seat properly. The cap must make a good seal.

jk and this.

I'll search ebay for a clean one and order it. mine is pretty gummed up and I had to scrape off what I could. and I started it about thirty minutes ago witht he cap off and the level of the coolant only rose, no bubbles or anything like that.

[jkv45]

Need answers to this:

Is the level in the radiator up to the top when you open it after running and cooling off?

What does the temp gauge read when it happens?

[braaap]

Originally Posted by jkv45

Need answers to this:

Is the level in the radiator up to the top when you open it after running and cooling off?

What does the temp gauge read when it happens?

yes it is up to the top. last night i remember even taking the cap off and it was at the top.

temp gauge reads between half and redline. so 3/4. fan does come on between 3/4 and redline.

[jkv45]

Originally Posted by braaap

yes it is up to the top. last night i remember even taking the cap off and it was at the top.

temp gauge reads between half and redline. so 3/4. fan does come on between 3/4 and redline.

If that's the case I'm thinking the cap is not sealing and not holding pressure in the system.

Does the level in the overflow bottle rise immediately as it heats up from cold? It should't start to rise immediately, it should take some time before the pressure builds enough to allow coolant to move from the radiator to the bottle.

[braaap]

Originally Posted by jkv45

If that's the case I'm thinking the cap is not sealing and not holding pressure in the system.

Does the level in the overflow bottle rise immediately as it heats up from cold? It should't start to rise immediately, it should take some time before the pressure builds enough to allow coolant to move from the radiator to the bottle.

it takes some time. the coolant doesn't move until the temperature of the engine gets to around 1/4 up. and even then it doesn't really even move.


to answer your question, it doesn't rise immediately. only rises when the temp gets up.

[jkv45]

Originally Posted by quarterliter

Could passages in the radiator be plugged from the corrosion and gummyness?

This sounds like a possibility.

Because the filler neck was a mess, you'd expect that the passages would be also. If the temp doesn't come down when the fan turns on, it would suggest the radiator isn't radiating...

[braaap]

Originally Posted by jkv45

This sounds like a possibility.

Because the filler neck was a mess, you'd expect that the passages would be also. If the temp doesn't come down when the fan turns on, it would suggest the radiator isn't radiating...

the temp does in fact come down when the fan comes on, and does it rather quickly.

[DaBlue1]

Originally Posted by braaap

....it also did this in motion at 65mph around 8k rpm for about 2.5 miles. it slowly creeped to the top of the reservoir and leaked out onto the tire.

If the system is releasing pressure after 2.5 miles, one of the sealing components is bad. Since you replaced the cap already, try replacing the fill neck. Also trying another cap won't hurt either.
Given that the ambient temps in Maine are not that high, the quick overheating may be more than just the cooling system.

It may be a good idea to look at a few other items that may be causing you to overheat.

Do you have any carb mods done to the bike?
What kind of oil do you use?
What kind of spark plugs are in it?
How does the bike perform overall?

[braaap]

Originally Posted by DaBlue1

If the system is releasing pressure after 2.5 miles, one of the sealing components is bad. Since you replaced the cap already, try replacing the fill neck. Also trying another cap won't hurt either.
Given that the ambient temps in Maine are not that high, the quick overheating may be more than just the cooling system.

It may be a good idea to look at a few other items that may be causing you to overheat.

Do you have any carb mods done to the bike?
What kind of oil do you use?
What kind of spark plugs are in it?
How does the bike perform overall?

Just ordered a new filler neck. Calling it now its the filler neck, looking online at what they should look like, as appose to what is on the bike now...

I am busy at the shop here today, ill try and snap a picture. it has got to be the filler cap not getting a proper seal. hopefully will get here by the end of the week.

no carb mods, just cleaned the carbs yesterday actually. running mint.
teal container...repsol maybe? fully synthetic 10w-40
ngk stock temp range.
bike performs mint. starts great, idles great, goes through the gears great. just cant get over this damn cooling puking thing! lol

[DaBlue1]

If all everything else checks out and you still have the overheating issue, do a compression test. Also see if you can check the exhaust header temps. You may have one cylinder running hotter than the other and not know it.

[braaap]

Originally Posted by DaBlue1

If all everything else checks out and you still have the overheating issue, do a compression test. Also see if you can check the exhaust header temps. You may have one cylinder running hotter than the other and not know it.

totally forgot about compression testing and header temps. had to check header temps on my bandit a few weeks back when it decided to run like a fat kid in gym class.

if the filler cap doesnt work. ill get at it that way.

next post will be a photo of my filler neck.

[braaap]

ok. so check that out.

it was even worse before i scraped off some of the crap on it...

black line on the inside of the filler neck is raised? that is NOT a scrape mark, it actually is physically raised on one side of the filler neck.

why the hell would there be something raised on the edge not having a good seal? confused as hell ha...

[DaBlue1]

Maybe a spring or something gouged the inside making a rise where the seals meet. Definitely an issue. Is there a mark on the lower seal of your new cap?

[braaap]

Originally Posted by DaBlue1

Maybe a spring or something gouged the inside making a rise where the seals meet. Definitely an issue. Is there a mark on the lower seal of your new cap?

no sir. no marks or damage at all.

looking at other filler caps on google images there should be a complete circle. not this like half moon risen part of the filler neck. something aint right lol

[Ninjinsky]

I had a blocked radiator did this It corroded badly from VGC secondhand over a year or so. after a couple of miles the gauge would rise to red and it dumped water into the reservoir pushed by steam from the cylinder jacket and head. after it cooled a bit it would draw the coolant back into the engine
I thought all sorts of complex reasons but in the end realized I had omitted the ground strap when I fitted it and I think electrolytic action corroded it
Now a new rad, grounded and refilled with distilled water and antifreeze all seems well

Drain the system and try to blow through the rad through the bottom hose with the rad cap off If the flow is poor you won't get meaningful ammounts air flowing through.Mine was totally and completely blocked ( One side of the rad still being cold when the bike is overheated is another sign)

[braaap]

http://forums.ninja250.org/posting.p...&t=84065&tro=1

similiar issue, changing the filler neck resolved this inmates problem. problem solved for him, and hopefully me as well once it comes in and I change it out.

[braaap]

Originally Posted by Ninjinsky

I had a blocked radiator did this It corroded badly from VGC secondhand over a year or so. after a couple of miles the gauge would rise to red and it dumped water into the reservoir pushed by steam from the cylinder jacket and head. after it cooled a bit it would draw the coolant back into the engine
I thought all sorts of complex reasons but in the end realized I had omitted the ground strap when I fitted it and I think electrolytic action corroded it
Now a new rad, grounded and refilled with distilled water and antifreeze all seems well

Drain the system and try to blow through the rad through the bottom hose with the rad cap off If the flow is poor you won't get air flowing through

had poured fluid in when I drained the coolant last night when we looked at the waterpump. as fast as I poured the coolant in it rushed out without issue. partial blockage? maybe. as far as complete blockage? cant be. it really did rush right the hell out of the bottom tube of the radiator.

[Ninjinsky]

Originally Posted by braaap

had poured fluid in when I drained the coolant last night when we looked at the waterpump. as fast as I poured the coolant in it rushed out without issue. partial blockage? maybe. as far as complete blockage? cant be. it really did rush right the hell out of the bottom tube of the radiator.

From the cap it has 2 routes to the pump via the rad and via the block. are you sure this was through the rad? also you can try it without the stat in but you will need to fit the rubber seal from the stat to a large washer temporarily as there is no gasket in the stat housing.

[braaap]

Originally Posted by Ninjinsky

From the cap it has 2 routes to the pump via the rad and via the block. are you sure this was through the rad? also you can try it without the stat in but you will need to fit the rubber seal from the stat to a large washer temporarily as there is no gasket in the stat housing.

positive.

came out of the lower radiator hose.

[kxpower?]

Originally Posted by braaap

Here goes.

about a month ago I joined up here with intentions of buying a 250. well. I did. and it is having a cooling issue that since mid april I have yet to figure out.

replaced thermostat and radiator cap.

resevoir boiling up around highway speeds. 50mph or below the bikes temp stays stable, it even stays stable at the highway speeds, but the coolant resevoir fills up and starts to piss out.

opened the radiator cap about ten minutes ago, turn the bike on, no coolant is moving at the radiator cap at all. am i just being cheap and not wanting to replace the water pump?

last night I opened up the water pump housing, the pump moves when ticking over the bike. no, i didnt run it, tapped the starter and saw the thing move. did it a few times, had some play, but it moved. im talking slight play, maybe a quarter inch clock and counter clockwise.

refilled the system, and it seemed to run better up until higher rpm, did the same thing. We did most of our testing at a stand still, the fan comes on better with completely new coolant, but even so, still boils into the reservoir and leaks out the overflow tube. stays pretty stable at idle actually. and the thermostat is new, confirmed working when we boiled the old one (which worked btw...) and threw the new one into the boiling water.

im thinking water pump, but dont want to come to terms with my new found belief lol...

I know you guys can help, love this little bike and glad I own another one. never should have sold my first ninja 250...this things so nice to rip around town. if only it cooled right!

Just to throw something out here, have you checked that the fan is blowing in the right direction?? You say it's fine slow but acts up at speed maybe it works ok blowing air backwards sitting still then when you're moving the wind counter-acts the fan and the radiator loses air flow?

I don't recall if the + and - connectors are interchangeable but it would be easy enough to hook them up backwards.

[braaap]

Originally Posted by kxpower?

Just to throw something out here, have you checked that the fan is blowing in the right direction?? You say it's fine slow but acts up at speed maybe it works ok blowing air backwards sitting still then when you're moving the wind counter-acts the fan and the radiator loses air flow?

I don't recall if the + and - connectors are interchangeable but it would be easy enough to hook them up backwards.

blows correctly. my father already brought that one up. this whole thing is baffling ha. but honestly, i think the filler neck will fix the issue. doesn't keep pressure, and at a stand still idling it doesnt build up the heat to warrant boiling over.

[Ninjinsky]

Originally Posted by braaap

positive.

came out of the lower radiator hose.

Good sign

[kxpower?]

Originally Posted by braaap

blows correctly. my father already brought that one up. this whole thing is baffling ha. but honestly, i think the filler neck will fix the issue. doesn't keep pressure, and at a stand still idling it doesnt build up the heat to warrant boiling over.

Hmm. Like Paul says you could diagnose a water-side radiator blockage by seeing if there are cooler areas of the radiator when it's up to temperature.

I might just hook a garden hose up and wash the radiator out in both directions and see if anything blows out.

I think you said you already ordered one but the pressure cap necks are cheap like this one: http://www.ebay.com/itm/2002-Kawasak...p2054897.l5658