Kubota B7100 coolant flush Qs

[canucklehead]

I have an 80's model Kubota B7100, about 2800 hours. Coolant is looking brown and ugly. Today it was boiling off overflow as I drove slowly using brush cutter on heavy, tall field (I worked it pretty hard).

I've drained vehicles before and messed it up by not letting thermostat open, and then on refill, I created air locks.

1) Do I need to use an additive before flushing to help break down internal crud, calcification, etc..? If so, what product works well?
2) How long do you run the additive before flushing?

3)I know how to open draincock. Do I need to have it heated up first so thermostat is open and all the coolant drains from entire system? Should I run water though open rad as well (while running and/or warmed up)? How long do you run water through?
4) On refill, does rad cap need to be off until thermostat opens, or does it need to pressurize first?

Sorry, probably basic, stupid questions but I'd like to do it once, properly.

thanks for help.

 

[Egon]

There is no thermostat. There should be whistle on the overflow tube to alert you of high temperatures.

For flushing get a good adative and follow instructions.

Also clean the rad exterior.

The B7100 uses thermo - symphony principle for cooling. There is no waterpump. The case the fan and dynamo Are on is just a water manifold.

They do overheat when fully loaded on hot days so one must be aware.

 

[canucklehead]

thanks Egon. It was whistling.AND I picked the hottest day of the year (so far) to cut this field.

If there is no thermostat: to flush after the additive, do I remove rad cap and leave drain cock open and just keep running water through it until it looks clear?

 

[Egon]

I'm far from knowledgable on flushing. I would assume the initial application of cleaner should be circulated by running the tractor. Your method of flushing should work. Don't know about disposal of fluids in your area.