Best Radiator Flush for B7200HST

[Hitechluddite]

My B7200 has some scale in the radiator and overheats too easily. I have flushed it every spring the past two years I've had it with flush from my local NAPA which seems to clean it pretty well but by the next spring it's back. I use distilled mineral free water and green universal fluid at a 50 50 mix. What flush would do the best job cleaning the cooling system in this tractor?

 

[Skippydiesel]

If you are changing your coolant every 12 months you should not have to flush the system EVER!, as long as you use the same coolant ie only flush when changing coolant brand/type.
I would recomend replacing coolant every 2-4 years depending on the hours the machine is doing per year.
Water
Scale is usually caused by using hard (mineralised) water. If using distilled/RO/demineralised you should not have scale.
Coolant
Use a coolant concentrate suitable for your system - they are not all the same. If in doubt get a recommendation from Kubota/ a radiator repair shop/ well informed parts supply/etc.
Older machines with copper radiators use diffrent coolant to those with aluminium core radiators.
In general your 50:50 ratio is correct but check the instructions on the container.
The COLOUR OF THE COOLANT (green) IS NOT A INDICATION OF COMPATIBILITY with your system.
Thermostat
If fitted, replace it (& associated gasket). An old one may be sticking, inhibiting coolant flow + overheating.
Radiator Cap
Replace with correct cap (pressure rating).
If system fitted with expansion/overflow reservoir make sure the cap is correct for this system.
If no expansion reservoir, only fill your radiator so that the coolant covers the core (look in top) leave the "top tank" with an air space to accommodate coolant expansion when hot.
Radiator Hoses
If older than 5 years - replace.
If cooling system does not use an expansion tank - make sure bottom hose is reinforced to prevent collapse. This is usually a wire coil in the hose (can be reused) or a wire reinforcing in the material of the hose. When replacing coolant hoses do the lot, including the overflow/expansion tank hose
Radiator
After each mowing- use compressed air (NOT WATER) to clean radiator & screens (if fitted) to maintain good air flow
If for some reason you have contaminated your cooling system with a material that cause sludge/solids/scale to form -, You could try removing the radiator and back flushing it using your garden hose. If severely blocked, this may not help, you will need to get the radiator professionally flushed/cleaned out or purchase a new radiator.
Fan & Coolant Pump
Ensure the belt drive is in good condition and sufficiently tight so that manual turning of the fan is quite difficult.
Pump - any leak must fixed. In the past seals/bearing could be renewed, these days you replace the whole pump (get a gasket lit to suit).
Chaff screen
If fitted - Will require, at the very least, daily cleaning. In some conditions/machines, cleaning during the working day, may also be required.

Hope I have covered most of the areas that could give you overheating problems. Address one issue at a time. Start with the cheapest/easiest to do and see if that fixes your overheating, before moving to the next "fix" and so on

 

[Hitechluddite]

Thanks for the excellent detailed reply! I have no idea on the history of this 30+ year old tractor. I have changed all the fluids and filters since purchasing 2 yrs ago. I'm just trying to get it in the best and most reliable operating condition possible. I just rolled the Hr meter over I'm hoping that's the first time this has happened

 

[Skippydiesel]

I love old equipment - such satisfaction in bringing it back to good working order.
If your tractor is that old, you might want to consider having the fuel injection system (pump & injectors) reconditioned.
You could also remove the fuel tank and have it (steam) cleaned.
I would also consider using a diesel fuel conditioner, with algaecide (at least double the regular ratio).
Research the correct oils for engine & transmission. Using the wrong oil may lead to grief.
Diesel engines seem to last forever, with the correct care.

 

[Hitechluddite]

So here’s my radiator before flushing I checked the water pump today and at a low idle. I’m pumping full volume that the hose will permit so the water pumps good, fan belt and upper and lower hoses are original but are soft and not crimp anywhere is also the belt is tight no squealing, or slipping noted.
I’m going to start another flush this afternoon. I will post a picture of the radiator after cleaning. I found a replacement radio online for about $200 but looks like it would be a better to replace so I’m saving that for last resort.

 

[Skippydiesel]

It certainly looks a bit like scale BUT could be residue from your coolant concentrate.
Double check you are using the correct coolant, for this Kubota's cooling system.
In all my years of playing with engines big & small, I have never had a situation where regular flushing of the cooling system was required.
Yes, when I got an old engine in, that may have had tap water or worse, used in the cooling system, extensive flushing/mechanical cleaning, even replacement of components, was done. After that, filled with the correct coolant, provably only changed the coolant at 4 years (no further flushing).

 

[Hitechluddite]

This weekend I reverse blew out the radiator with compressed air. This seems to have helped.