Coolant drain and refill procedure

[Towncivilian]

I need to drain and refill my radiator soon. I'm uncertain of the procedure. This is what I've understood so far:

• 1. Set heater controls to maximum heat and run blower motor for 10 seconds with engine off, ignition at "ON"
• 2. Open radiator cap and rear air relief valve at rear center of engine
• 3. Remove radiator overflow reservoir, drain and clean with distilled water, reinstall
• 4. Drain coolant using drain plug at bottom of radiator
• 5. Pre-mix 1 gallon Genuine Nissan Coolant + 1 gallon distilled water using a suitable container
• 6. Fill radiator to neck? When do I close the air relief valve?
• 7. Fill overflow reservoir to MAX line?
• 8. Run vehicle at idle to burp air from radiator, and make sure coolant is topped up?
• 9. Drive around for a bit watching temp gauge, verify heater operation, top up coolant when required?

Can someone clarify the questions?

EDIT: Scroll down (or click post6003182.html#p6003182) for the correct process.

[Chuck Tribolet]

You fill the radiator to the bottom of the neck, wait five minutes, top up the rad, install the air relief cap but not the rad cap. Now
run it till the coolant starts to circulate and idle another five minutes, top up rad as required, install rad cap.

You missed step 4.5: Tighten the drain plug

There's stuff in the maintenance section of the FSM.

[Towncivilian]

How do I remove the coolant overflow reservior? Do I need to remove a headlight? It sure looks like it.

[CanuckQx4]

Ya to remove the the tank you have to remove the headlight and maybe even the bumper to get at the lower bolt.

Best way and less time consuming it to simply drain it of coolant and run water through it a few times. You can drain it quickly by taking off the overflow hose from the rad neck, and routing the hose down and out of the engine bay below the overflow so the coolant all comes out, then you can simply flush it with water and empty it out.

Theres no real point in removing the overflow, just empty it by bringing the hose completely below the tank

[Towncivilian]

Yea, that's what I'm gonna do right now. I just drained and filled the radiator, gonna do the same for the overflow now.

[Towncivilian]

Ok, flushed the reservoir with distilled water. Bunch of sediment came out, I'm glad I flushed that.

Anyway, I filled the rad to the bottom of the neck before I flushed the reservoir. Afterwards, I filled it to the mouth and started the engine and waited for coolant to circulate. Temp was barely above C on the gauge. It looked like it was about to overflow, so I shut it down and put on the rad cap. Started it up again, rev'd engine a few times. Temp was at normal (half-mast). I shut the engine off and tried to open the rad cap to check the level, but it spurted out somewhat after about half a very slow turn. I quickly put the rad cap back on (luckily I wrapped a bunch of paper towels around my hand and I didn't get burned) and wiped off whatever spurted out. I'd assume that was normal. What to do now? Overflow reservoir is still at "MAX". Haven't found any leaks. I did the drain and refill on a slight incline.

[Towncivilian]

Drove to a friend's house, overflow reservoir is now empty. Once the engine cools I'll fill the rad if required and fill the overflow reservoir. Heat is still functional.

[Towncivilian]

OK, everything's fine now. Here is the procedure that worked for me:

• 1. Set heater controls to maximum heat and run blower motor for 10 seconds with engine off, ignition at "ON".
• 2. Open radiator cap and rear air relief valve at rear center of engine.
• 3. Drain coolant using drain plug at bottom of radiator.
• 4. Unclip radiator overflow reservoir hose next to rad cap and route it below the engine so the contents of the reservoir can drain. Flush using a gallon of distilled water. Mine had a lot of sediment, which is why I used a gallon.
• 5. Pre-mix 1 gallon Genuine Nissan Coolant + 1 gallon distilled water using a suitable container, such as a new gas can that holds 2+ gallons. Reinstall drain plug, make sure the O-ring is still present!
• 6. Fill radiator to bottom of neck and wait five minutes. Fill overflow reservoir to "MAX" line.
• 7. Fill radiator to top, install air relief valve cap and radiator cap.
• 8. Run vehicle to operating temperature (don't drive around just yet). You can rev the engine to around 2k RPM to speed this process up once the temperature gauge starts climbing. Watch for temperature spikes and verify operation of heater. Once at normal operating temperature, shut off the engine.
• 9. Check overflow reservoir level. Fill to "MAX" if necessary. Once it's at "MAX," you can now drive as normal. Watch coolant reservoir level and check for leaks periodically (every time you park, ideally) and top up to "MAX" if required. If the overflow reservoir becomes empty, top up the radiator and the reservoir once your engine is cold and the rad cap is no longer hot, and continue this process until the coolant level no longer drops (or if you cannot wait for your engine to cool, just top up your reservoir and check/fill radiator at next convenient opportunity).

Easy enough of a process. Let me know if I missed something!

[Towncivilian]

The coolant level in the overflow reservoir is now steady at hot and cold at about double the "MAX" capacity. Should I drain some out or just leave it as is?

[attofarad]

How much of the coolant is drained (how much is left in), when you just open the radiator drain? I have no data on what green coolant was used last time it was changed. I had been planning to do a distilled water flush before refilling with Zerex Asian -- which comes already diluted.

I wouldn't want to end up significantly under 50% by water remaining in the system.

Anybody open the two block drain plugs, as in the FSM for the 2001 QX4?

Gary