Radiator fan doesn't come on

[R4V3N]

Hi Guys

Problem:

After about 10-15mins of running my busa cuts out - the temp gauge goes to the top/red mark and the fan doesn't come on.

Background:

• The coolant is the non water expensive stuff. Plus I ensured all air was out of system at the time.
• I have inspected the fan relay - seems ok.
• I have connected the fan straight to battery to test is actually works - and it does.
• I have replaced the thermo/fan switch and with the honda one as recommended on another post here.

Ive read somewhere that it takes around 10-15mins for the engine to get to temperature?...

so as it cuts out after this amount of time am i right in thinking the thermostat is jammed closed or open?

AND... would this be the reason the fan is not coming on? (my thoughts behind that are - if coolant is not able to pass through/round the engine then the coolant won't reach any temperature and wont activate the fan switch?)

Also Im running a 4-2-1 yoshi stainless full exhaust - not sure if this makes any difference to anything (ive read they can melt your fan blades but thats it!?)

Please can someone let me know if im on the right track or if not please point me in the right direction lease:
plus any other advice would be greatly appreciated

its getting to the point where im close to fixing it with the "BIG HAMMER" so thanks very much in advance

[foose]

Hi Guys

Problem:

After about 10-15mins of running my busa cuts out - the temp gauge goes to the top/red mark and the fan doesn't come on.

Background:

• The coolant is the non water expensive stuff. Plus I ensured all air was out of system at the time.
• I have inspected the fan relay - seems ok.
• I have connected the fan straight to battery to test is actually works - and it does.
• I have replaced the thermo/fan switch and with the honda one as recommended on another post here.

Ive read somewhere that it takes around 10-15mins for the engine to get to temperature?...

so as it cuts out after this amount of time am i right in thinking the thermostat is jammed closed or open?

AND... would this be the reason the fan is not coming on? (my thoughts behind that are - if coolant is not able to pass through/round the engine then the coolant won't reach any temperature and wont activate the fan switch?)

Also Im running a 4-2-1 yoshi stainless full exhaust - not sure if this makes any difference to anything (ive read they can melt your fan blades but thats it!?)

Please can someone let me know if im on the right track or if not please point me in the right direction lease:
plus any other advice would be greatly appreciated

its getting to the point where im close to fixing it with the "BIG HAMMER" so thanks very much in advance

hi, i dont know much, but the basics go this way..
1.check if the coolant pump is working propoerly, u could also ensure this by seeing if there is proper fluid flow in the coolant system.
2. when the engine heats up, the fan relay should be energised to run the fan, so, just startup the engine , wait for it to heat up, and check if the relay is getting voltage with a multimeter(12v i guess). if it is getting power, then the trouble is upstream- the thermo.
3.If u suspect the thermo, then slightly tap it to relieve it of the stress or stuck position.refer the manual for its location.

[R4V3N]

how would i check to see if the water pump is working? - is it common for them to fail?

[Dscahill]

Check for pressure to be building up in the cooling system by gently squeezing the hose while its running. It should be firmer than when cold. Also, you may try simply removing the t-stat and letting it warm up that way (unless you don't mind swapping out out for a new one anyway, start on the cheap and work your way up!)

-D

[MC MUSTANG]

How did you get the air out of the system?

[Busa1166]

engine cuts off???


My engine has gone into the red and motor has never cutoff. I have had to turn it off myself with the kill switch


Fan failing to turn on maybe a separate issue???

[Trout]

Nobody has mentioned the fuse.

My fan stopped working for a while. It was a blown fuse.

I inspected the fan cage and found a little rock in there. I suspect that maybe the rock jammed the blades while I was riding and caused the fuse to blow.

Check your fuse. It might be that easy.

[dadofthree]

Nobody has mentioned the fuse.

My fan stopped working for a while. It was a blown fuse.

I inspected the fan cage and found a little rock in there. I suspect that maybe the rock jammed the blades while I was riding and caused the fuse to blow.

Check your fuse. It might be that easy.

He stated he ran the fan straight off the battery so that eliminates bad fan motor, stuck fan blades, bad ground. Well, did you check the fan fuse ? Don't have a description of how you ran the fan to the battery. I believe you stated the fan relay and switch were good as well. Make absolutely sure you don't have air in the system and then pop that thermostat out I guess.

And no, water pump failures must be rare, because I have never heard any post a failure and we have numerous members over the 100K mark.

[R4V3N]

ok thanks guys
sorry yes i did check fuse and its ok.
when i filled with the new coolant i just followed the instructions on the bottle which said something like...fill up to just below neck of rad, start bike up with rad cap off and let warm up and watch for bubbles releasing. then turn off bike replace cap, then rock bike side to side and repeat.

does this sound right to you guys????

i didnt think/hoped it wasn't the water/coolant pump so i think next step is to change thermostat?

do you guys agree?
thanks again! :smiley10:

[Poppy]

Based on what you have described....I would re-install the OEM fan sensor and see if that corrects the problem. If still a problem, check the thermostat with a pan of water on the stove and a thermometer.

[DanielandAlma Stair]

Is this happening while parked in you driveway or while on the highway.
seems to me if you jump the fan to the battery and start the bike one of 2 things will happen
1 the bike will overheat, you have a problem in your cooling system...either pump, thermastat, or blockage somewhere. And maybe a electrical issue with your fan circut.
2 the bike stays at operating temp. You have an electrical issue somewhere in the fan circut.

[dadofthree]

ok thanks guys
sorry yes i did check fuse and its ok.
when i filled with the new coolant i just followed the instructions on the bottle which said something like...fill up to just below neck of rad, start bike up with rad cap off and let warm up and watch for bubbles releasing. then turn off bike replace cap, then rock bike side to side and repeat.

does this sound right to you guys????

i didnt think/hoped it wasn't the water/coolant pump so i think next step is to change thermostat?

do you guys agree?
thanks again! :smiley10:

Sounds good but you might have to repeat that. Have you got it worked out yet ?

[teginder81]

The attached diagram from the service manual may help in tracing the problem. Maybe first try and power the fan up from a 12V source?

[R4V3N]

just to let you guys know - it was the thermostat (final thing).???

So all in all my cutting out problems have been down to (and if you have similar probs check): tilt sensor, relay, fuel pump, thermoswitch and thermostat.

(now wonder she was being a pig) - so back on the road and no cutting out wooooh!

thanks for all your help!!

Also this is probably not the right place to ask but does anyone know where i can get the fuel rail section to convert from external to internal fuel pump? there is 2 on ebay at the mo but £40 shipping to uk:huh2: bit much

thanks again

[dadofthree]

Check with Daniel Goldenchild


Glad you got it fixed.