Troubleshooting Cooling System - 6th Gen

[elwray]

I picked up a used 03 VFR last week. Already changed the oil, brake fluid, clutch fluid, chain, sprockets. Last night tried to tackle the coolant.

Drained from both bolts, made a huge mess, re-bolted then filled with distilled water and flushed. Did that twice (making a huge mess both times). Then torqued down the two drain bolts and filled, while on the side stand, the filler neck above the right radiator with green Prestone 50/50. Then filled the reserve tank on the left side to almost the upper line.

Idled with the caps off, revved it a few times and rocked it a little side to side. When I revved, coolant dribbled out the filler neck a little bit at a time.

Eventually the temp rose to 180*F at which point the thermostat should have opened, however I realized at 185*F that I had no idea how I would know. So I capped the filler neck on the right side, and let it go up to 223*F (from the LCD readout) and the fan didn't come on.

It was suggested that I had an air bubble in the left radiator? Is that where the fan temp sensor is? It definitely wasn't nearly as hot on the left side as the right side.

Should I have had the cap on while it was running in order to build pressure? I'm just thinking now that with the cap off, the hot coolant would rise and just come out the top instead of circulate...

I'm hoping it's just an issue with the way I ran it with the cap off, or have an air bubble. I'm really not looking forward to draining the coolant (and making another huge mess) to check the thermostat or try and trace electrical connections in the fan

Should the level have risen or fallen in the reserve bottle with the cap off? It didn't move or heat up.

Any suggestions? Thanks for any help!

[elwray]

For any interested, just took her for a run and idled for a bit. Thermostat seems to be opening, hot on one side and moving it to the other. Then the fan came on at 221*F!