Coolant tank level

[CREnorth]

Need a little help to figure out whats going on with the coolant level in the overflow tank.
The bike has almost 8000 miles on it and seems to be using coolant. I have added about a gallon at this point. I've looked for leaks and there is none. It's not going in the crankcase, oil level and color are perfect. It does not look to be going out the exhaust pipe, clean and no smell.
I was thinking that there might be an air space in the system and it would fill and be fine but it's been doing this for quite some time now and not getting better.
The dealer looked to see if there was any tsb's on this topic and there was none. The radiator itself is full and the system works fine, get's hotter under a load and cooler when as it should (fan on, down hill ect.)
Would like to hear from anybody who has had this issue or just any advice on what to do.

 

[Koinz]

I haven't put a drop of coolant in 8000 miles. Definitely something going on. Any white smoke out the exhaust indicating that it's being burnt.

 

[stevepsd]

Hi Gary,

I have added not a drop to mine.....and since I am in a climate that is probably a little hotter than yours I think we could rule out evaporation.

A gallon is almost twice the capacity of the cooling system itself, so ..... if it is not leaking out, or leaking in (you sure the oil level is not rising by itself - (these quasi dry sump motors are difficult to get accurate/repeatable oil level readings), the only other thing it could be is that it is being burned by being sucked into the combustion chambers thru a bad head gasket or casting flaw in the head/cylinder.

How much are you adding and how many miles?

Your dealer should have a cooling system pressure tester - they are used to test pressure caps but also have a attachment to fit onto the radiator and then you pump up the pressure in the cooling system and check for leaks....with the internal ones being a bit more difficult to isolate and usually by process of elimination. But the coolant is going somewhere.

They could also add a cooling system dye and have you run the bike around then check things with a UV light, including draining the oil and seeing if it shows up in your crankcase.

Have you checked around the radiator end caps, which would require removal of the left side cowling?



Now, you don't have any buddies that are playing tricks on you now? We did that back at the bike shop with one of our sales guys who was obsessed with fuel mileage, so every couple of days we would add some gas to his bike and his fuel mileage kept going up & up & up. We kept it up for several weeks. It was hilarious to watch & listen to his stories about how great his bike was (it was a Honda CB750 Automatic!). We should have started to siphon some out each day so it would drop & drop & drop, but we did not. We never did tell him.....

 

[CREnorth]

Hey Steve,
as far as the amount added and how many miles, I fill the tank to the full mark before start up and at the end of a days riding the tank is almost empty. Could be 150 to 250 miles.
I have stoped at different intervals and looked around for leaks or maybe a coolant smell and can't find anything. The level just get's lower throughout the day.
Im sure it's not going in the crankcase, the oil looks very good.
There was one time when stoped (the engine was at normal temp) I seen the level droping and you could hear the engine pulling it in. That's why I was thinking air in the system. That was the only time I seen it do that.
I will have it pressure tested like you said. Thought about mounting the Go Pro at the tank vent hose.

 

[Glenn C]

Could be a faulty radiator cap. These are actually a pressure valve. As the coolant heats up and expands, it is released into the reservoir. If the reservoir was already at the full mark AND the cap releases at too low a pressure (ie faulty), this could explain your problem. As mentioned, the dealer should be able to pressure test the system (including the cap).

BTW, coolant being sucked back out of the reservoir would be consistent with the above because when the engine cools, the cap should allow coolant to be drawn back into the system.

Worth getting it checked out I think.

Cheers
Glenn

 

[stevepsd]

Hey Steve,
as far as the amount added and how many miles, I fill the tank to the full mark before start up and at the end of a days riding the tank is almost empty. Could be 150 to 250 miles.
I have stoped at different intervals and looked around for leaks or maybe a coolant smell and can't find anything. The level just get's lower throughout the day.
Im sure it's not going in the crankcase, the oil looks very good.
There was one time when stoped (the engine was at normal temp) I seen the level droping and you could hear the engine pulling it in. That's why I was thinking air in the system. That was the only time I seen it do that.
I will have it pressure tested like you said. Thought about mounting the Go Pro at the tank vent hose.

And after it cooled off, the tank is still empty? There is not that much air space in the system. It has to be going somewhere..... No tale-tell signs of dried coolant anywhere on the hoses, coolant tank, water pump or motor (it normally dries to a white-ish looking powder)?

The reservoir holds 8 ounces of coolant, which is approximately 1/8 of the total cooling system capacity, so losing this amount is significant.

 

[Koinz]

Gary, the interesting thing here is that you say it runs fine and doesn't over heat. If I were losing that much coolant in a short period of time, I would immediately say it's a head gasket issue but you typically have overheating associated with that. In any case, I would be cautious about riding the bike until you have determined where the Antifreeze is going. It could be doing more damage than good. :'( :'(

 

[hojo in sc]

The coolant has to be going somewhere, I ride in extreme heat and never see a drop in the level.

 

[CREnorth]

I haven't put a drop of coolant in 8000 miles. Definitely something going on. Any white smoke out the exhaust indicating that it's being burnt.

Nope, no white smoke out the pipe. The pipe looks just as it should and no coolant smell. I took off the radiator cap today and the level was a bit low so I added some and let it run for like 30 min. The fan came on and off about 6 times.
No leaks and seems to be ok. Im going to get it pressure tested on Sat. Maybe that will show a leak.
Thanks for the input guy's.

 

[Koinz]

Nope, no white smoke out the pipe. The pipe looks just as it should and no coolant smell. I took off the radiator cap today and the level was a bit low so I added some and let it run for like 30 min. The fan came on and off about 6 times.
No leaks and seems to be ok. Im going to get it pressure tested on Sat. Maybe that will show a leak.
Thanks for the input guy's.

Hi Gary, I was curious to hear whar your dealer found regarding your mysterious coolant loss. Any news?

 

[CREnorth]

After talking to the service dept. on the phone I could not bring myself to letting them work on the bike. So what I did was take the tank off and psi test it. Just like you would think it's good. I never did psi test the system itself. (I did not have the small adapter for my tester) When taking the radiator cap off I seen the level was a bit low so it got toped off and the tank filled to the line.
I've put on maybe 400 miles stoping and looking at the level many times and it's at the same spot. There seems to be no problem now. So what im thinking is I never checked the radiator level on the bike (old guy memory loss) and it was delivered to me very low on coolant and it kept pulling from the overflow tank.
I guess the amount of coolant I've added is a bit over 1/2 gal. If this is what happend im kinda suprised the bike ran cool and the temp guage worked as it should.
Im still concerned and look at the level before and after every time the engine is run but so far the coolant loss has stoped.

 

[Koinz]

Well, good to hear that your issue turned into a non-issue. Thanks.