[Roadsters] Cooling system maint before/after reassembly

[Graeme]

"I drained the radiator to have it tested over a year ago. Pretty cruddy
muddy rusted agua consistent with the condition of the radiator, which got
tossed.
L20b block drained to whatever level not having a hose on the water inlet
would drain to. 
Finally getting ready to reassemble. I'm thinking I should remove the
thermostat and flush backwards with a hose.
Anything else I should do?
Thank you.
Pete"

The L series blocks have a drain fitted to them, it is a hex head plug
located about 6" beneath spark plug #4.
I would advise removing it and back flushing the engine from that point.
Could be a tough job to remove. 
If it gets trashed, replace it with a BRASS plug to avoid corrosion issues
in future.
Make sure all othe coolant connections are opened up to allow any flaky crud
to escape.
If the block has been sitting for a year with some residual coolant in it ,
it may be quite dirty.
When you fill the engine with coolant add some System Cleaner and run that
for a few days or as per recommendations.
Then you can drain, re-flush and re-fill with a good quality coolant like
Nissan Long Life Coolant.

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