'02 QX4/VQ35DE engine coolant drain and refill

[brickbox]

Folks,

Got a quick question about engine coolant drain and refill. I followed the old post that Towncivilian described in an old post years ago.

I followed it down to the T. Now with the drain and refill, I only got a gallon out. So there's about 1 gallon of the Zerex Asian stuff while the rest is still the old Nissan green from a very long time ago.

Here's a picture of the pressure relief on the back of the engine bay. There's crud in there as you can see which I think makes the thing not function as designed. Is there a way to pull that stuff out without letting it fall into the tube?



Reason I am asking the above is, it took the car about 10 miles to truly burp itself which was mostly on after I put her in "1" instead of "D" and floored her. Then and only then did I start getting heat and a steady temp gauge. Prior to that, the temp gauge would start rising anytime I turned heat off or was just puttering around town.

Any of this seem normal?

[brickbox]

Anyone?

[04pathse]

Did you look in the FSM on how to do the procedure?

[brickbox]

Did you look in the FSM on how to do the procedure?

Kinda. I referred to the maintenance section of FSM.
I did not open the 2 drain plugs on the water pump and right side of the engine. I did open the air relief plug on the back of the engine (the one with rust/crud as shown in the first post).
FSM states there's air relief "plugs". Where is the other one?

I can't find a picture in the FSM for the other air relief plug.

[yeldogt]

The OE fluid its green .. but it's not the same as the old USA green fluid.

I do simple drains of the radiator and and wash it down -- clean the fill tank all using OE fluid and distilled water. Never an issue --

The engine has two thermostats -- you are better off at idle with cap off and heater on vs driving -- and you don't want to race the engine.

The full flush is only be necessary if the wrong fluid is in the car -- these engines are sensitive and it's important to do occasional refresh.

[brickbox]

The OE fluid its green .. but it's not the same as the old USA green fluid.
The engine has two thermostats -- you are better off at idle with cap off and heater on vs driving -- and you don't want to race the engine.

I don't plan on messing with the thermostats. I saw where the lower (?) thermostat was buried during the VCG change, I would hate to have to touch that.
Not sure if this car has regular green, it looks a lot darker than the generic Prestone/Peak stuff from the autoparts store.

By cap off, I assume you mean the overfill/reservoir cap - correct? I plan on doing another gallon this weekend along with attempting the fuel filter (way too much rust on that 10mm bolt )

[brickbox]

That's the old fuel filter - pretty sure its original! Installed a new K&N fuel filter.
Which is slightly smaller - any ways to secure it in place? The bracket with the 10mm bolt is on TIGHT but it can still move.

Also for the burping question of the engine coolant - looks like letting the engine idle without the overflow reservoir cap for about 5-6 mins and then driving the car in "1" or "2" is the way to get rid of any air pockets.

[yeldogt]

No you leave the cap off the radiator .. that's how you fill it. Not the overflow bottle. My point with the two thermostats is that they both must open fro the fluid to flow and to expel the air .... you don't want to be running up the RPMs without have coolant everywhere. After its properly filled the cap can be put on the the overflow filled to the proper level.

[brickbox]

No you leave the cap off the radiator .. that's how you fill it. Not the overflow bottle. My point with the two thermostats is that they both must open fro the fluid to flow and to expel the air .... you don't want to be running up the RPMs without have coolant everywhere. After its properly filled the cap can be put on the the overflow filled to the proper level.

I did not realize you could run the car without the radiator cap. Won't it spurt all the water out?

[yeldogt]

the water will only spurt out when it's under pressure -- the cap provides this pressure. w/o cap ... no pressure. The system needs to be filled prior to the cap going on ..so you want to run the engine up to temp so the thermostats open and the heater is on full. This will allow the coolant to flow throughout the system and any air will come out the open cap. Install cap and drive car .....The level should be checked again after driving and cool down .. open cap and fill up if needed.

The system is more of an old school system vs a more modern system where the overflow is more integrated into the system. The over flow is designed to take and give a little to the cooling system .... it will not fill the system like some modern cars will.

Cooling systems are pressurized to raise the water temp boiling point --- with cars engines needing to run hotter for efficiencies the run under greater pressure

[PRATEHGEE]

Same thing happened to my 01 Pathy. I assumed that the cooling system needed to be bled and since my pressure relief was clogged with rust/s*** just like the picture you posted, I took a Phillips head screwdriver with rubber mallet and went to work. I'm pretty sure it worked because after filling the radiator with new coolant and starting my car, coolant and air started to flow out. After a couple minutes, my temperature gauge evened out and I replaced the pressure relief cap. Just my 2 cents though, good luck.

[brickbox]

Thanks both! I haven't been able to work on the car last couple of weeks. Its been HOT outside! Waiting on the weather to cool into double digits before I get back out.

[AlabamaDan]

I just drained and refill my 98 QX4 with Prestone for the last 10 years....

[brickbox]

So I went to do a drain and refill. The little drain bolt kept seeping. So I went to tighten it just a hair and it snapped!!
How do I pull that little sucker out so I can replace it with a new one?

Also, I tried the keep radiator cap off and let car idle.
I had a whole bunch of coolant run out (the level would keep rising and falling) as the engine got up to running temperature. Once the bubbles stopped, I turned the car off and put the radiator cap back on.

The temp gauge went to 1 tick below "H" twice before settling down.
Is this normal?

[brickbox]

Since I can't edit the previous post - here's a picture of the snapped drain bolt.

[AlabamaDan]

Oh no! I think the answer is screw extractor set, but I've never had to do this with an engine bolt.

[brickbox]

Oh no! I think the answer is screw extractor set, but I've never had to do this with an engine bolt.

That's exactly what I ended up doing. What a PITA - had to be careful not to strip any of the radiator threads.
Got another gallon of the Zerex Asian (red) stuff in. All good!

I must admit though, the burping engine with radiator cap off works for the most part, but I still had to drive it around town to get the temp gauge to stop hovering around. Also, when the system was burping, holy moly does it spew coolant everywhere

Overall, I got 4 gallons of the fresh stuff in. I should be set for the next 50k miles.

[Rockwood]

Just a factoid for you: the freezing point of pure ethylene glycol is actually about 10 degrees above zero. 60% antifreeze and 40% water is best - it freezes about 45 below zero. So you may want to check with a tester and be sure your freezing point is low enough.

Hope your cruise control is still working ok!

[brickbox]

That's a good idea. I have one of those cheap Prestone testers. Just gotta find it.
The original green Nissan coolant has -45F protection and since I got the 50/50 mix (couldn't find the concentrated pink/red stuff for Asian vehicles within 50 miles of me), I would think that the protection is still the same with better anti corrosion properties in there.

The coolant gallon jars said protection for 150k miles/15 years, but I plan on changing out the coolant in about 50-60k miles. Interestingly, the owner's manual states that the factory coolant was supposed to replaced after the first 60k miles and then every 30k miles. But then again though, I believe that engine coolant formulation has come a long way when compared to 2002.

Cruise control still works! Haven't taken the hammer to the bracket yet to straighten it.....yet!

[Rockwood]

My brain automatically went to 100% antifreeze when I read your post. If you used 50/50 you are good!

[barnaclebob]

I never messed with the drain plugs in the engine or the air bleed valve in the back of the engine. One of these was super handy and contained any overflow from the engine:

https://www.amazon.com/Lisle-24680-Spil ... B00A6AS6LY

I just did a drain and fill using 50/50 with the car slightly tilted to the passenger? side to help the fluid drain from the radiator.

It took a few driving cycles, burping, and adding a little more fluid to the reservoir before the heat would work again.

[AlanAZ]

Here's a picture of the pressure relief on the back of the engine bay. There's crud in there as you can see which I think makes the thing not function as designed. Is there a way to pull that stuff out without letting it fall into the tube?

The curd is carbonized rubber of the cap - the cap extended inside the tube in addition to outside. I removed my 'plug' using a drill bit, smaller than the tube so that it's not metal on metal, and turning it by hand, periodically vac'd out the pieces with a shop vac. Once you break through completely, turn the shop vac into a wet vac, and using duct tape to seal the gap, give the tube a vacuum. After emptying the wet vac, vac some clean water to clean it.

In addition to relying on the bleeder tube, I floor-jacked the hell out of the front of the truck to raise the radiator filler cap well above the engine, and filled slowly to allow air to bleed out.