Kawasaki VN750 Forum banner

1 - 20 of 20 Posts

·
Steve
Joined
·
71 Posts
Discussion Starter #1
I read the great thread on changing oil coolant. I did it all from the orginal pocket book manual, but it did not talk about teh bleeder valve. I took the bike for a run and it ran really hot and spewed out coolant from the overflow. Before I changed the coolant this did not happen on the old coolant. So I read the trhread and undid the bleeder valve, but no coolant came out, even afteroverflowing coolant out teh neck. I actually took the whole bleeder valve out but no coolant came out. Is thi normal ?

Hopefully to fix the overheating I ran the bike with the radiator cap off, reved the bike until some coolant went down after some bubbles, until it started to heat up and expand out the neck. I put teh cap on and let the fan come on a few times. The heat range was about teh middle of the range. I assume this is the normal range when its all working fine. I used 33% glyocol. Designed for cars. Am I an the right track ?
 

·
'03 VN750 "Rosie"
Joined
·
227 Posts
The glycol coolant we use in the states needs to be mixed 50/50 with water, not 33%. My guess is the weak solution you used expanded more than a 50% solution would have and it boiled over. As for the bleeder valve, I don't know why nothing comes out of it. I flushed and filled mine a few months ago and I could easily see coolant coming out. Maybe poke a paper clip into the bleeder hole to unblock it, then flush the whole system according to the thread you found here and try again.
 

·
romeobravo172
Joined
·
842 Posts
Could have been a large air bubble in the system. When refilling the system add the coolant slowly, this helps a lot to eleminate air bubbles. Sometimes do not have to use bleeder.
 

·
Premium Member
Joined
·
3,027 Posts
The bleeder valve is completely worthless. I've changed my coolant several times, and never used it. It is only a few inches from the filler, so it doesn't really do anything. The main things are to use the right coolant mix, and pour it in very slowly, with the engine running. The thermostat needs to be open and the water pump needs to be turning so the coolant can circulate. Fill it very slowly up to the bottom of the fill neck, as the engine starts warming up, the coolant level will start to rise in the filler neck. When that happens, put the cap back on and tighten it. Fill the reservoir about half full. Then go for a ride, come back, and let the engine cool off. Do this a couple of times, and fill the reservoir to the full line. The hot engine will expel coolant into the reservoir, then suck it back in when it cools down.
 

·
Steve
Joined
·
71 Posts
Discussion Starter #5
Thanks. This is what I have been doing, ie I went for ride today at 100 kms per hour and it was fine, but when I rode around in first and 2nd gear, the temp got hot to about 3/4. When I stopped I could hear the coolant boiling and some came out the overflow again. I was giving it a hard time with clutch extra. Is this normal for it to get so hot , in stop start traffic ? If so what can I do ? I am only running 33% glycol . Do I have a blockage ? I did leave the cap off, and let the air bubble out the top, even rocked it side to side.
 

·
Banned
Joined
·
10,354 Posts
Hopefully to fix the overheating I ran the bike with the radiator cap off, reved the bike until some coolant went down after some bubbles, until it started to heat up and expand out the neck. I put teh cap on and let the fan come on a few times. The heat range was about teh middle of the range. I assume this is the normal range when its all working fine
In theory, youve now "bled" the system...granted a PITA, but works. Would be nice if someone made a radiator cap that size with one of those air bleeding levers...hmmmm....million dollar patent idea here....
This post is copywrited by Wolfworks Enterprises, Inc.
 

·
Steve
Joined
·
71 Posts
Discussion Starter #7
Is coolant coming out the overflow and at 3/4 temp mark normal in heavy traffic. ? I can here the coolant bubbling in the overflow tank. Is that normal ?
 

·
Registered
Joined
·
619 Posts
Never had a bike that hot if it is boiling maybe the themostat isnt opening and not allowing the hot water to circulate
 

·
Steve
Joined
·
71 Posts
Discussion Starter #9
i will pressure test the cap first. If its ok, I will replace the thromostat.
 

·
Registered
Joined
·
619 Posts
The cap will just blow open if the bike is to hot even if it is good thats what is designed to do, if you say the water is boiling then it will open to release the pressure but it shouldn't be that hot in the first place, the only things I have come accross is to cause this is a stuck thermostat, blown head gasket, air blockage, or gunge blocking the waterways.
 

·
Steve
Joined
·
71 Posts
Discussion Starter #11
Thankyou for the tips. I think the headgasket is fine as it runs well, and no oil in the water, or visa versa. I flushed the coollant out twice, and with a aliminium raditaor cleaner as well. I have ran water through it for about 5 minutes, and release all nuts, including th ones on the heads, and water pump and flushed out the overflow.

I am will replace ther thermostat which I can order new from Kawasaki and see how it goes.
 

·
Premium Member
Joined
·
4,778 Posts

·
Steve
Joined
·
71 Posts
Discussion Starter #13
Thanks again the Kawa dealer has aftermarket caps for $14 aud ($13 USD), so I will have a spare in anycase. I asked him about the relationship between caps and overheating. He said its the first thing they test, as it is more likely to fail. He continued, when the bar drops from 1.1 to about 0.7 or 0.8 then it depressurises the cooling system too early and puts fluid back into the resevoir.

He said the thermostat can drop out of the housing on disaseembly so take note on which way it comes out, as sometimes they can fit in both ways. He said the thermostat is less common to fail.

Anyway I have ordered both, and it will come in the post and save me a trip accross the river. Its raining any 18 degrees. c
 

·
romeobravo172
Joined
·
842 Posts
On the bike after filling with coolant ( or water ) and running for a while the level should drop meaning thermastat has opened. Out of the bike take into your kitchen ask for wifes best pot ( cooking kind ) add h2o & thermostat , HEAT. You can visually see it open & close.
 

·
romeobravo172
Joined
·
842 Posts
Not reading back, does your fan come on as your guage gets clooser to the red? Think usually on autos water pumps do not usually fail, they leak.
 

·
Steve
Joined
·
71 Posts
Discussion Starter #18
Yep, fan comes on. I am guessing thermostat is stuck closed. I could test in a pot of water, but wil wait a day until my radiator cap turns up....much easier to fix.
 

·
romeobravo172
Joined
·
842 Posts
Can test on bike without the cap, fill up , crank up, and watch to see if level drops after a few minutes. You would do this anyway doing a coolant change.
 

·
Steve
Joined
·
71 Posts
Discussion Starter #20
It never did, I was mopping up the overflow with a rag... I guess that solves it then. I will fit the thermo on the weekend.

Thanks for the advice.
 
1 - 20 of 20 Posts
Top