How To Replace/drain Coolant From Radiator And Block Rb25det [video]

[Joni Boi]

Hey guys

I made tutorial video on draining and replacing the coolant on a RB25DET aswell as changing the thermostat:

I did it according to what the Nissan R34 Service Manual says. My first tutorial, so let me know what you guys think.

[PranK]

Brilliant! I've added to DIY index.

[dyl33]

Good stuff! I'll add this for extra info.

[z00key]

Awesome, great work

[-S-]

thanks! good work on the video. im hoping its the same for the r33 .

for the next few flushes do u still need to use radiator flush?

[tridentt150v]

I would have taken that stone tray off as well though, just makes it easier and less splash/dribble............but really good Tutorial.

[Joni Boi]

thanks! good work on the video. im hoping its the same for the r33 .

for the next few flushes do u still need to use radiator flush?

I only used it for the first flush. I suppose you can if you want to. I don't know much about radiator flushes, it's not like you need it, it just makes the flush process faster I guess. They're only about $10 for 500ml at supercheap

[AMR33]

Good tutorial

[mikel]

dragging up and old but very useful thread...

great tutorial - well done!

What did the other members of the household think about testing the thermostat in the kitchen kettle??? ?

Is there any way to get the old coolant out of the block without removing the block drain plug?

I've read in other threads you can remove the thermostat housing and thermostat and use a hose and tap water and flush out the block using the thermostat entry - but on a quick check with a torch tonight it looks like the thermostat housing is nowhere near the bottom of the block? so you'd end up with tap water in the block, and even parked downhill the thermostat housing looks too high to drain all the water/coolant from the block?

Given the difficulty of accessing both the block drain plug and thermostat housing, I'm leaning towards dumping the radiator fluid, refilling with radiator flush + demineralised water and repeat a few times, then put Nissan LLC concentrate + demineralised water in...

...or doing the same, but going to the effort of getting to that biatch block plug for the first drain and the last before the Nissan LLC concentrate goes in, and not touching the thermostat housing (in some respects the thermostat looks harder than the block plug - ie remove stuff/3 bolts/clean surfaces/new gaskets or goop etc)

My question is - if I don't remove the block drain plug, will that turn 2 flushes into 5 or 6 (or more) to get the old coolant out? Is it worth dealing with the block plug to get a better cooling system flush with less repeats of flush/demineralised water required?

cheers

Mike

[mikel]

I've decided the best option is to tackle that block drain plug - the current coolant is green, and my 5 litre Nissan LLC bottle contains blue stuff...I don't want to contaminate the Nissan LLC blue coolant goodness.

The Nissan manual specifies "3 Bond 1386B" for the thread on the block drain plug, which of course my local auto parts store doesn't stock

From a search on the Googleweb, "3 Bond 1386B" is a welch plug sealant - can any product that's labelled for use as a "welch plug sealant" be used?

Guidance on suitable products sold at places like Supercheap/Autobarn/Repco would be very helpful?

cheers

Mike

[Joni Boi]

Yeah, I was actually ment to post earlier to say that there would be no other way that I can think of to get all that old coolant out of the block without un doing the drain plug. I was going to suggest removing the lower coolant hose from the radiator but the thermostat will be in the closed position when engine is cold. So the plug is the best way. Just get underneath the car like i did and un do it. I never knew nissan had it in a blue color. Mine was green. I just used normal thread sealant from loctite which you can get anywhere. I also bought a new coolant drain plug (Nissan Part No: 08931-3041A) from a Nissan dealership for like $5. 

Let me know how you go.

 

Edit: looking back at this video, I can't believe I did that whole tutorial hungover lol

Edited February 16, 2019 by Joni Boi

[mikel]

4 minutes ago, Joni Boi said:

I never knew nissan had it in a blue color

I didn't crack the bottle...after your post I just went and looked again - for some reason it has a blue tinge when looking at the liquid through the transparent strip on the side of the bottle, but splash it up the strip and it's green...

12 minutes ago, Joni Boi said:

I also bought a new coolant drain plug (Nissan Part No: 08931-3041A) from a Nissan dealership for like $5

Thanks heaps for the part number - that makes things way easier to get a new one if required ?

20 minutes ago, Joni Boi said:

I was actually ment to post earlier to say that there would be no other way that I can think of to get all that old coolant out of the block without un doing the drain plug. I was going to suggest removing the lower coolant hose from the radiator but the thermostat will be in the closed position when engine is cold.

And watching your video, removing the thermostat housing seems harder than removing the block drain plug!

Also on a quick scan with a torch, the thermostat housing still doesn't appear to be low enough in the block to get all the old coolant out - hard to see much, but it's higher than the oil filter...

...I guess that's why the Nissan manual says to remove the block plug

Well done again on the great tutorial video - I've watched it many times now.

I laugh every time when you pull the block drain plug out - the couple of expletives (completely justified) contrast so well with the rest of the "no voice over" approach - and the final bit in the dark...clearly not a quick job!

I still want to know what your household members thought about the thermostat in the kettle??? or did they never know??

cheers

Mike

[Joni Boi]

5 minutes ago, mikel said:

I still want to know what your household members thought about the thermostat in the kettle??? or did they never know??

haha I was going to replace that kettle and thought, hmmm... I'll use it one more time for this video. 

[silviaz]

On 4/26/2016 at 10:49 AM, dyl33 said:

Good stuff! I'll add this for extra info.

I imagine the procedure is the same for the rb25det neo, except only difference being is the 2 air release plugs to bleed the coolant instead of one?

[dyl33]

On 05/03/2025 at 10:02 AM, silviaz said:

I imagine the procedure is the same for the rb25det neo, except only difference being is the 2 air release plugs to bleed the coolant instead of one?

I believe that is correct

[silviaz]

One quick overthinking question, is it safe to drive the car for 5-10 mins with only distilled water in the system so it gets to operating temperature faster? I know of course I can warm up it up idleing but was just curious. As Rb's can tend to run quite hot and it's an iron block as well not sure if rusting is a factor here.

Edited June 13 by silviaz

[PranK]

Yeah I reckon that's fine. Just watch the temp.