Coolant changeout. Reservoir? “OAT”?

[SmallChange]

I’ve never done a coolant change on something with an overflow reservoir before, and now realize I don’t know how. The manual says “Engine cooling system - Drain fluid“ every 2 years.

In addition to draining the radiator itself, do I also need to drain the overflow reservoir? I’m guessing so, because it’s supposed to be able to go back and forth into the radiator contents with hot/cold cycles, but I can’t find anything about this tractor or about cars generally that says to do this.

Also, the manual says:
You should not mix OAT coolant with conventional coolant. Mixing OAT coolant with conventional coolant will reduce the effectiveness of OAT coolant. If you need to change a machine from conventional coolant to OAT coolant or vice versa, you should follow the “Changing coolant types” procedure below to attain the full benefit of the coolant.

They go on to describe doing two exchanges with pure water and half hour runs, to flush out the old before putting in the new.

The part of the manual discussing an ordinary engine coolant change (without changing OAT versus the other) says to run a garden hose into the radiator fill, keep the radiator drain open after draining the coolant, and run the engine with this fresh water running through it until what drains out is clean.

If I bought the tractor new, and bought replacement radiator fluid from the same tractor dealer who told me it’s the right stuff, can I assume I’m not changing between these two types? The radiator fluid I bought from them is 50/50 premixed Zero Original Green which says it uses “Inorganic Additive Technology (IAT)” “Relied upon for decades by automakers worldwide”, which sounds to me like the opposite of “OAT”.

I’m guessing I should flush the running engine with the garden hose, but don’t have to do the two half hour wash cycles. Is that right?

 

[RjCorazza]

I’ve never done a coolant change on something with an overflow reservoir before, and now realize I don’t know how. The manual says “Engine cooling system - Drain fluid“ every 2 years.

In addition to draining the radiator itself, do I also need to drain the overflow reservoir? I’m guessing so, because it’s supposed to be able to go back and forth into the radiator contents with hot/cold cycles, but I can’t find anything about this tractor or about cars generally that says to do this.

Also, the manual says:
You should not mix OAT coolant with conventional coolant. Mixing OAT coolant with conventional coolant will reduce the effectiveness of OAT coolant. If you need to change a machine from conventional coolant to OAT coolant or vice versa, you should follow the “Changing coolant types” procedure below to attain the full benefit of the coolant.

They go on to describe doing two exchanges with pure water and half hour runs, to flush out the old before putting in the new.

The part of the manual discussing an ordinary engine coolant change (without changing OAT versus the other) says to run a garden hose into the radiator fill, keep the radiator drain open after draining the coolant, and run the engine with this fresh water running through it until what drains out is clean.

If I bought the tractor new, and bought replacement radiator fluid from the same tractor dealer who told me it’s the right stuff, can I assume I’m not changing between these two types? The radiator fluid I bought from them is 50/50 premixed Zero Original Green which says it uses “Inorganic Additive Technology (IAT)” “Relied upon for decades by automakers worldwide”, which sounds to me like the opposite of “OAT”.

I’m guessing I should flush the running engine with the garden hose, but don’t have to do the two half hour wash cycles. Is that right?

I would personally drain the overflow tank also. As far as OAT, HOAT, etc... It's generally a bad idea to mix any different coolant chemistries. Worse things can happen than just reducing the effectiveness of the new coolant.
When I have changed coolant types in the past, I would thoroughly flush the system (similar to your garden hose statement), however, I would finish flushing by running two cycles of distilled water through. That way there's no tap water left in the block.

Back to your new coolant... Sounds like you're changing out standard green to standard green. If the coolant system is current on maintenance and not neglected I would simply drain and replace without flushing.
The standard green is a 2 year coolant, whereas OATS and HOATS are generally 5 year coolants. The first thing I do to new machines is switch to Zerex G05 (HOAT) for the 5 year interval. Choosing a long life coolant requires some research to ensure compatibility, so I'm not saying that my coolant choice is correct for your application. Some coolants (DexCool comes to mind) will wreck a system not designed for its use.