cooling problem

roadrun_fr · Post by **roadrun_fr** » Thu Aug 18, 2005 6:28 pm

Today I returned to home. It was a warm day.
Riding in town, the temperature increased to 110Â°C = 230Â°F.
The fan did not start.
When I reached home, the temperature increases to 112Â°C = 233Â°F and I stopped the bike.
The "cooling tank" rejected some antifreeze per its higher hose (1/4 liter) with a little sound like "blubblublub" near the "thermostat".

I switch the key on with motor stopped: the fan didn't start, temperature at 112Â°C-230Â°F.

I waited until temperature decreased to 110Â°C (230Â°F) and restarted the bike.
The fan does not started until it reached 112Â°C (233Â°F) and then started.
Then temperature decreased to 110Â°C (230Â°F) then fan stopped and the temperature reincreased to 112Â°C (233Â°F) then fan restarted and so on.

Usually, the fan starts at 108Â°C-226Â°F (that is high my taste) but today, it started at 112Â°C-233Â°F and I lose some antifreeze.

What should I check ?
bleeding cooling system ? Replace Thermocontactor on the radiator ?
Thermostat ? Too much cooling antifreeze ?
I've checked antifreeze level last week and it was precisely at the "full" mark on the "cooling tank"

bluesman · Post by **bluesman** » Thu Aug 18, 2005 6:59 pm

first of all - feel lucky you have such beatiful weather!

check if fan sensor working (the one that actually switching fan on).

And check thermostat (boil it to see if circuit opens). Then check radiator cap if it does open to early (pressure set by spring) then too much coolant can leak to expansion tank...

Did you changed coolant recently?

roadrun_fr · Post by **roadrun_fr** » Thu Aug 18, 2005 7:05 pm

fan sensor seems to work but later ... And the storm lost antifreeze although it didn't reached max temperature ...

bluesman · Post by **bluesman** » Thu Aug 18, 2005 7:06 pm

I was just adding some things to my message - sorry....check my post again

roadrun_fr · Post by **roadrun_fr** » Thu Aug 18, 2005 8:07 pm

I've changed coolant last year ....
radiator cap seems to be a good idea... that would explain "filling" expansion tank and "blublubblub" because of not enough pressure in cooling circuit ...

roadrun_fr · Post by **roadrun_fr** » Fri Aug 19, 2005 7:38 pm

I've checked one thing.
Starting the bike in the garage and waiting for it reaches 105Â°C-221Â°F, the expansion is beeing filled at mid level of its complete volume.
The fan starts today at 106Â°C but it's a colder day and I have ride the bike.

Sounds like the radiator cap open too early no ?

radiator cap is stamped 1.1 (1.1 bar = 16psi), at which temperature would the cap open normally ?

Only the radiator cap can fill the expansion tank ?

Post by **kevg** » Fri Aug 19, 2005 11:38 pm

i don't know anything about the rad cap, but the fan comes on with my bike at 105 degrees and goes off again at about 100, i've a 2002 model with the temp gauge on it.
hope this might be of some help in finding what range it should work at.

Stratman · Post by **Stratman** » Sat Aug 20, 2005 12:08 pm

Just a thought, but shouldn't the full mark only be reached when the engine is up to operating temp? If you filled the system to there when cold then it would be overfull and discharge the extra when it got hot.

roadrun_fr · Post by **roadrun_fr** » Sat Aug 20, 2005 10:52 pm

I've replaced the radiator cap by a "used" one. Cost me 5 bucks.

Seems that it works !
- The coolant now doesn't fill the expansion tank at 105Â° (level increase only very few)
- the hose that goes from the radiator cap to the expansion tank is not hot, telling me that no coolant is flowing here
- fan kicks up at 106Â°C
- no "blublubblub" sound after several cooling cycles

Stratman, the upper level should be check at cold time.
Expansion tank has enough capacity in normal conditions to accept coolant expansion.