coolant vented onto leg in explosive manner - .: XT660.com

kneebone · # 1 29-08-09, 00:13

I was riding home this evening when I hit what I guess was the famed "bank holiday traffic" about 5 mins from home. I sat in traffic for about 10 minutes when the temp light came on. I couldnt hear the radiator fan coming on because of the other traffic and the rain (so I cant tell if it came on at all). Was debating just turning engine off and letting it cool but I was about 5 metres from the traffic lights that was holding up the traffic.

Then the bike vented coolant in a big plume of white smoke over my leg from the right hand side of the bike upper engine area. I turned it all off the engine and stuck the hazards on and pushed it to the pavement and had a look at it.

As far as I can tell the coolant expansion chamber (usually only about an inch of coolant visable) was full (1cm space from top!) due to it expanding as it heated. Seems as it had no where to go it blew out one of the clips on the tubing around the top of the engine (to the left of the spark plug looking from the right hand side) and vented the excess coolant onto me. Due to being wet and wearing thick bellstaff overtrousers I didnt get burned but it was pretty large amount of smoke and I certainly felt the power behind it.

That didnt strike me as a particularly safe way to vent the coolant, but its clearly not supposed to do that :P Pushing it home, Ive since toweled off all the excess coolant and the bikes sitting outside with its cover on. Starts ok and the temp warning no longer comes on.

Ive since reattached the blown rubber tubing and clamped the metal clamp back in place. Im going to drain the coolant tomorrow (seeing as it is still too high dispite me not putting any more in since.. well ever as its just done routinely with its services). Im going to attempt to book it it for its MOT for next week as well, (due on the 2nd) but is there anything else I should be aware of/look at, or any potential damage that may have occoured as a result?

cheers

Kev · # 2 29-08-09, 07:44

Sounds like the cooling fan did not come on.

When the coolant light comes on switch off the motor straight away as it is over heating, if driven in this state you will damage the motor.

kneebone · # 3 29-08-09, 09:33

Yeah, now its light outside Ive had a look at it.

Tried spinning the fan manually and it was a bit hard/wouldn't free spin when poked with a finger. Seems like it has siezed somehow or the moter's gone. It moves, but i dont recall it being that reluctant to do so. With the coolant not getting cooled it just built up in the resevior before something had to give.

Well, hopeully no permenant damage done. Off to the garage in 10 mins to get a quick once over and go through parts preordered I want for a service before 4th year MOT.

cheers Kev

jiauka · # 4 29-08-09, 11:42

Could be the fan itself, the temperature sensor, but my guess is that the thermostat inside the hose/radiator got stucked, I would replace it and clean all the hoses/rads/etc... in order to be at the safe side.

have fun,

j.

kneebone · # 5 29-08-09, 14:57

Had a look at the fan this afternoon. I would have had a decent look but it seems the fan is mounted to the radiator with tamperproof bolts so I can't actually get the unit off to look at it. I've taken the back of the fan off and cleaned it all up/lubed it as best as I can seeing as i cant take it apart further. It certainlty spins more freely but less so than the random bikes I fiddled with at the garage earlier.

Still currently fiddling. Cleaned most of the radiator which I was amused to find was manufactured by KTM. The coolant levels seem to have returned to normal slowly over the course of the day without it leaking everwhere. (well a few drops here and there but not the several cup fulls it would take to drop that much). Its now sitting neatly between the "min and max" levels.

Going to play around with it somemore in a sec

Kev · # 6 29-08-09, 15:00

You can check the operation of the fan through the dash in zone 51 & can check the temp sender reading on zone 6 against a thermometer.

Could also be a stuck thermostat, feel the coolant hose coming out of the thermostat it should be a similar temp as the other hoses when the bike is at operation temp.

The fan must spin freely when turning it by hand.

kneebone · # 7 29-08-09, 15:40

Fan now spins just fine by hand. I can actually flick it and it keeps spinning a few times where as before it barely moved.

Reading on zone 6 is 18C

Tried the fan operation on Zone 51 as stated. Get the continuous electronic noise (same as when kill switch is turned on for fuel injection on startup) but nothing happens. Its obviously sending the command to the fan but the fan is deaded. BOO!

Well that explains the overheating!

Guess its time for a new fan unless the guys in the shop can actually take it apart and get it running.

Cheers for the advice. While Im playing around with the diag I may as well do your fueling tweak seeing as the bike is now out of warranty

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