My 350 Saturno overheated for the first time today. I had to stop and let it cool down for a few minutes several times during the trip home. It was a warm day but not overly hot. I've certainly ridden it on hotter days without any problems in the past.
I checked the coolant level in the radiator when it cooled down and it was down a little but not much. My radiator cap is a bit marginal and probably not pressurizing the system to the optimum pressure but it isn't leaking. The only other things I can think of looking at are the thermostat or the water pump. How much flow should I be getting through the top hose on the radiator when the engine is warmed up?
Is the cooling fan cutting in (and out) properly? What is the level in the expansion tank doing? Going up but not down when cooled off might indicate a head gasket problem. Loss of coolant could also be a sign of that.
Worth checking the thermostat. As to the coolant flow rate with a good pump I'm hoping Kano Nordi might know the answer.
"Do not adjust your mind, there is a fault in the reality" 1957 175 Sport, 1993 GFR
I've had very similar problems with my 350 Saturno. I eventually removed the thermostat and it seems to be OK, however, my water pump started leaking on my last ride, so it could be the pump wasn't working to it's maximum efficiency?. I don't think they are the most wonderful pumps in the first place from what I read. The other things I replaced were the gauge thermostat sender,the radiator cap and the fan switch on the radiator. If it was working Ok before, then as has been said, I would check the fan function.
Worth checking the thermostat. As to the coolant flow rate with a good pump I'm hoping Kano Nordi might know the answer.[/quote]
Sorry 72 no idea what the flow rate is and its variable with engine speed, with standard straight vanes on the impeller i doubt they are very efficient, I seem remember PEMOPA doing a curved vane, If everything else is in order the pump s adequate or Gilera could not have got away with it!!