Another overheating thread !

[gillebob]

So I bought an 02 ie model a month ago and by the time I got it home the needle was in the red even though the fan came on at around 80 degrees but continued to climb til I stopped to let it cool down. So a brief look round it showed water in the oil but no other signs of obvious head gasket failure so replaced the water pump seals and no more water in the oil.. But still appeared to be overheating so kept looking.. the expansion tank level never seemed to move up or down so guessed the radiator cap wasn't releasing any pressure and the build up of pressure I assumed was what caused the pump seal failure.. just put a new read cap on and now it's releasing pressure but only when the gauge reaches near the top at almost 120 degrees and the bike still seems to be overheating, fan coming on still at 80 but keeps climbing.. I don't seem to have oil water or water in oil, the fan comes on when it should and the red cap seems ok now but I'm stumped.. any suggestions?

[stisma]

Let's assume the water pump impeler was secured to the shaft properly and both seals were facing the correct way.
How about the thermostat, behind the water pump?
When the engine reaches the operating temp, see if one side of the radiator is cooler than the other....feel the coolant tubes, hot and cold.


PS. 80*C for the fan is a bit early, since the operating temp is at 80*C.

[gillebob]

Yeah impellor rotor shaft and seal all good, had the thermostat out and tested before doing the pump seals. The radiator is looking a bit manky although it doesn't seem to be leaking and there's a good flow through it. What's confusing me though is that the gauge keeps going up after the fan cuts in. Is 80 really too low for the fan to come on? I thought the fan switch was set at that.

And both sides of the rad and the hoses seem to be at the same temp.

[gillebob]

And seeing as though the radiator is hot both sides is it possible the coolant is flowing through it without being cooled?
would that indicate a fault with the rad?

[stisma]

B4 we start pointing to the head gasket, few things to do/check....
Make sure the temp shown is in fact the engine coolant temperature (bad temp sender, loose wire, ....)
Perhaps the temp shown is not the correct/true engine temp.
For that I use IR thermometer and point it at the:
- termistor (temp sender for the temp gauge, one that has only one wire)
- thermal switch for the fan ( two wires)

[gillebob]

Thanks stisma but my brief aprilia experience has come to an end. Sold it as a project and bought a Honda cb500.
Hopefully it'll be more reliable and easier to get spares.