1990 Nissan 300 ZX Turbo - Episode 6: One Dozen Coolant Flushes

[@freewayz32]

I have to do this to mine.

[@kaedekurosawa]

Isnt there a bunch of coolant/water still in the system, like in the motor/ blocked by the thermostat even after you drain it via the petcock? You didnt tell us how to drain it completely in order to put the new coolant in once you flush it and clean it.

[@autoobsessivegarage]

You’re totally right that water could be trapped in there. After this many flushes while allowing the vehicle to heat cycle multiple times almost everything is completely flushed out. Pulling the thermostat makes the process easier.

[@garmagui]

There are 2 screws for the coolant drain on the engine block, near the engine supports on each side. The right side is close to the oil filter, aside to the alternator (genius placement). It is very difficult to reach, removing the oil filter may help, so you end up changing oil too.

[@HelldogPC]

It Took me 30 flushes :( someone had left only water in the system ahhhh

[@autoobsessivegarage]

Some people are just the worst. I’ve seen many a cooling system rotted away due to that…and the kicker is that it was sometimes done to mask overheating issues.

[@3lija11]

I have a question sir. Is it possible to do a coolant flush on a non running 300zx ?

[@autoobsessivegarage]

It certainly is. They sell flush kits where you can attach a garden hose and run water up through the cooling system. You may want to take out the thermostat as it won’t open this way.

[@jschwartzlow]

Do you think it took longer because you don't open the block drain plugs?

[@autoobsessivegarage]

Maybe. I feel like most of the heavier sediment was settling in the heater core and radiator...which is probably why it required so many flushes.

[@jschwartzlow]

@@autoobsessivegarage Thanks. I recently replaced all coolant lines. I was shocked at how clogged and corroded they were. I will likely beat your record 12 flushes before it is over.

[@tomekczajkowski9922]

Hi what coolant I should use green? Thanks

[@KyleFeauxSho]

​@@tomekczajkowski9922 I'm sure you've gotten your answer by now, but yes - green