This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Overheating problem, no fan: 2004 Mille

D

dirkster

Joined Aug 2009
5 Posts | 0+
Hi there,

my 2004 Mille R overheated yesterday on a hot day riding in the city of Berlin. Coolant was boiling. Lost about 1/2 Gallon of coolant. Fan didn't came on. In my instrument panel the temperature was not exceeding 90-94 degrees Celsius. Water boils at 100 Celsius!

Any idea of the source of the problem? Where is the sensor for activating the fans? And how can I measure if it's working?

Thanks a bunch,
Dirk
 
dirkster said:
Hi there,

my 2004 Mille R overheated yesterday on a hot day riding in the city of Berlin. Coolant was boiling. Lost about 1/2 Gallon of coolant. Fan didn't came on. In my instrument panel the temperature was not exceeding 90-94 degrees Celsius. Water boils at 100 Celsius!

Any idea of the source of the problem? Where is the sensor for activating the fans? And how can I measure if it's working?

Thanks a bunch,
Dirk
Click to expand...

Fans on mine normally kicked in around 96 so if the ecu is being told 90 -94 it's possible that there isn't anything wrong with the thermal switch just that the ecu is getting mis information on the real engine temp.

See my reply in post "help efi warning"

failing that thermal switch, burnt out fan/fuse etc
 
camngetit said:
the fans seem to come on at diff temps mine are on around 80 - 82c
Click to expand...

pre 04 bikes have a different (lower) fan kick in temp and a 2 sensor temp setup whereas post 04 is single sensor. what you see on the dash post 04 is what the ecu is being fed also.

Pre 04 the ecu and dash use different sensors so what you see on the dash may not be what the ecu is getting.
 
Thanks a lot for your feedback.

It's an 04, so we can assume it's a single sensor?!?

According to the user manual the fan fuse "E" is also securing fuel injection and coils. This rules out a blown fuse, since the bike wouldn't run at all anymore.

I will check the type of the sensor tomorrow, in another thread there are discussions about the blue ones being known for problems: http://www.apriliaforum.com/forums/showthread.php?p=2276204#post2276204

Can I short-wire the cables to the sensor to emulate an overheating to kick the fans in or do I have to be within certain resistance (Ohm) levels?
 
dirkster said:
Thanks a lot for your feedback.

It's an 04, so we can assume it's a single sensor?!?

According to the user manual the fan fuse "E" is also securing fuel injection and coils. This rules out a blown fuse, since the bike wouldn't run at all anymore.

I will check the type of the sensor tomorrow, in another thread there are discussions about the blue ones being known for problems: http://www.apriliaforum.com/forums/showthread.php?p=2276204#post2276204

Can I short-wire the cables to the sensor to emulate an overheating to kick the fans in or do I have to be within certain resistance (Ohm) levels?
Click to expand...

The diags will sense a short and throw a warning if you short the wires.

you could measure it at temps below and see how it varies from suggested spec.


resistance 2.5 KΩ (at 68°F)
resistance 220 Ω (at 212°F)
 
spoonz said:
The diags will sense a short and throw a warning if you short the wires.

you could measure it at temps below and see how it varies from suggested spec.


resistance 2.5 KΩ (at 68°F)
resistance 220 Ω (at 212°F)
Click to expand...


Wow! Thanks a bunch! Just for others who will Google this up in the future with the same problem in metric countries:

68F = 20C
212F = 100C

I will check this tomorrow and will keep you posted...
 
...one more troubleshooting idea/question: If I use a 200 Ohm resistor to bridge the wires at the sensor, the fans should come on if the relays and the fans work, right?
 
Can you not run power through a toggle switch right to the fan? Ignore the sensor & just turn on a fan manually when you are stuck in the city...
 
OldTZracer said:
Can you not run power through a toggle switch right to the fan? Ignore the sensor & just turn on a fan manually when you are stuck in the city...
Click to expand...

Hahaha, I love punk rock style moves, I did this with a KLR as I was traveling 4 months in Central America with no local access to spares. But for an 04 expensive nice Mille I don't put a Kragen Autoparts switch on my handlebar if I can isolate the issue, order and replace the broken part.

PS: Used to race an old TZ250 a few years ago, too! :)
 
I put one on my RZ500 years ago & had it tucked out of sight behind the guages.

It would have been nice to have the fans come on this morning as it was only 8c when I left for work & my knees were cold...
 
×

New Posts