Tutorial: R32 Gt-r Radiator Removal And Coolant Flush

[lwells]

The purpose of this tutorial is as a step-by-step guide for R32 GT-R owners who wish to remove their radiator for flushing, and to completely remove and replenish all coolant within their car's system.

Given the number of R32 GT-Rs that have recently been imported and their often unknown service history this is an important piece of maintenance for owners who wish to avoid the possibly catastrophic consequences of blocked water galleries, overheating, corrosive and impure coolant.

Whilst the radiator removal process is quite well documented, the complete flushing of coolant -- including from the engine block -- is not, hence this tutorial. Whilst researching the correct procedure/s I found the following resources very helpful (I suggest you at least glance at them):

1. PranK's R33 radiator replacement guide.

2. R33 (I assume? Or is it R34?) radiator removal and filling procedures.

3. R32 GT-R workshop manual coolant filling procedures.

4. R32 GT-R workshop manual radiator parts breakdown.

5. R32 GT-R workshop manual exhaust parts breakdown.

6. R32 GT-R workshop manual air drain plug diagram.

In terms of tools and equipment, you will need access to the underbody of your car, a good ratchet and socket set (in particular, sockets 12mm through 16mm). Depending on the size of your tools, your mileage will vary: as you will see, I had to use a number of items from my sidchrome set when it came time to remove the engine drain plug.

In terms of time, the radiator removal is a very quick process and should take no longer than 30-60 minutes. Removing the rest of the coolant is a much harder job for the home mechanic due to the location of the plug and will, if my experience is any indication, take a whole day.

Finally, remember when working under a suspended car to take necessary precautions to ensure that, should your jack or stands fail, that you will not be injured.

Removing the radiator:

This proved to be easier than I had imagined -- about a 1 out of 10 on the difficulty scale and quite quick (~30 minutes of solid work).

1. Turn the ignition on and set the climate control to max heat (32 degrees). The R32 GT-R workshop manual actually says to "remove the external sensor connector" once the ignition is on, but later manuals (for R33/34) say just to set the heater to max (which is what I did). Apparently this is meant to release any fluid in the heater.

2. Remove the undertray. (No pictures, sorry. If you can't work this out you shouldn't even be attempting this at all )

3. Remove the coolant reservoir tube.

4. Unplug the thermoswitch sensor wiring. You will need a small screw driver to get the clip integrated into the plug to let go.

5. Place a 5L bucket/tray under the drain plug. Open the drain plug (on the bottom right of the radiator, looking front on) and remove the radiator cap. The coolant should start to gush out of the radiator.

Here is a picture of the drain plug on the (removed) radiator:

6. Undo the hose clamps for the top radiator hose (it can be useful to do both ends so you have more play in the hose) on the left of the radiator, and wiggle the hose off. Don't be too violent: old plastic and rubber doesn't necessarily like being disturbed.

7. When the coolant has completely drained (unless you are like my dad who got covered in coolant because he was impatient), undo the clamps holding the bottom hose (bottom left of the radiator) in place and wiggle the hose off.

8. Remove the two screws along the top edge of the radiator (closest to the windscreen) that hold the fan shroud in place then remove the lower section of the fan shroud: it just clips in place. Below you can see some pictures of the shroud when removed: it should give you a good idea of how the lower section clips on.

9. Undo the nuts that hold the radiator mounting brackets in place; remove the brackets.

10. Very carefully wiggle the radiator a bit and lift it out of the engine bay. Its extremely easy to damage the fins so be patient. Thankfully the radiator is quite light and easy to handle. Be careful not to loose the mounting rubbers on the bottom of the radiator.

11. My fan shroud was still held on by one screw (I don't know if this is normal). Simply remove the screw, lift the sides of the shroud and wiggle it off the radiator.

12. Unscrew the coolant reservoir bottle: the two screws at the bottom on either side of the bottle. Dump the coolant from the bottle.

You now have a bare radiator in all its glory and a nice space in the engine bay. Woo! How easy was that? Have a look at the coolant from your system as it will give an indication of the health of your cooling system: the coolant that came out of my system was in surprisingly good condition.

Radiator flush:

At this stage it was off to radiator shop to have the radiator professionally flushed. There are two types of radiator flush: a simple air flush, and a more complex 'power flush' which seems to involve removing the end tanks and slotting a cleaning tool down the fins.

I opted for the standard flush which involved submerging the radiator in a big tank of water and ramming a stupidly huge amount of air through it (in the reverse direction, i.e. from bottom to top), causing a nice wave that splashed over yours truly This should blow at any crud that has accumulated over the years.

In my case, it was all very good news: very little came out from the flushing and the radiator guy said it was the best radiator he had even seen and was rather amazed when I said it was 15 years old. In his words, "obviously the previous owner maintained the car!".

For reference, flushing cost me only $20. Even though my radiator proved to be in excellent condition, the peace of mind alone is well worth the very cheap cost. While at the radiator shop I purchased some coolant: the guy recommended a mix of 2:3 coolant:water (i.e. 40% coolant). Given that the GT-R takes about 8 litres of water/coolant, that meant 3.2l of coolant which set me back $30. I also purchased a 5l bottle of distilled water for about $4 at Woolworths (make sure it actually says distilled on the label, not just pure/fresh/spring). Some people are happy with tap water but given the crud that comes out of our taps I would strongly recommend you don't skimp on a couple of bucks and stick water with who-knows-what minerals, metals and contaminants in to your cooling system.

[lwells]

Engine coolant drop:

Dropping the coolant out of the radiator only gets about half the coolant in the system: the rest remains in the engine block. Perhaps the ease with which I was able to remove the radiator lulled me in to a false sense of security, but dropping the coolant from the block is undoubtedly the single (physically) hardest car task I have completed. Be warned: I needed the better part of a day working solidly. The hardest part is actually getting to, and then undoing, the drain plug. You will need to remove the front (Y) pipes and cat, have the dexterity of Gumby, and the patience of an angel (or have neighbors who don't mind a constant stream of profanities ).

You should also probably get a set of new gaskets for the turbo dump --> front pipe joint, and cat --> exhaust joint. Due to time constraints, difficulty locating the gaskets, and specialist shops not being open, I had to settle with cleaning up the original gaskets and using a very light application of manifold cement.

1) Follow the front pipes up to where they join the dump pipes (sorry, no pics, couldn't get a decent shot). You will see two nuts per flange: undo the nuts a bit (although leave them on so the exhaust doesn't latter drop on your head ).

2) Remove the shield that covers the catalytic converter. Where the cat flange joins the rear exhaust flange you will see two nuts: again, loosen them but leave them on for now.

3) Just in front of the cat is a bracket that holds the exhaust in place. Undo and remove the nuts.

4) Undo the exhaust temperature sensor. Do not cut it. It is stainless steel and can't be soldered, and will have to be completely replaced if damaged. I couldn't get mine undermine so just left it in place.

5) Now remove the nuts from the cat --> rear exhaust section and wiggle the sections apart. Remove the nuts from the dump pipe --> front pipe flanges, and wiggle the front pipes off. Because I couldn't get my exhaust sensor undone, I had to take a bit of care to lay the front pipes down in such a way that there was slack in the cord for the exhaust temperature sensor.

6) Reposition yourself back towards the engine and try and spot the engine plug (ha, good luck!). When you finally see it, wonder how the f#ck you’re ever going to get to it, and what Nissan's designers were thinking.

7) You will need to remove the rear turbo support bar. First undo the turbo coolant line (the middle screw) and move the bracket out of the way, then undo the two bolts holding the support bar in place. Remove.

8) Again wonder how you're going to get at the drain plug. Without doubt this is the most difficult bit. A ring spinner will probably not be long enough, a ratchet + socket will foul on the turbo heatshield (as will most other tools). I ended up having to use most of the sidchrome collection, namely this concoction:

My ratchet + extension + universal joint + socket + bar to extend the handle a bit.

Even though I bent the turbo heat shield back a little and used the above concoction, it took me about an hour to get the f#cker undone. I just can't describe how difficult it was...

When (if!?!) you get it undone, grab a 5 litre bucket/tray, try and position then remove the drain plug. Your likely to get covered in coolant as it comes out very quickly and there are a number of obstacles it hits on the way down.

9) Clean up the drain plug.

Once the coolant has finished dropping, replace the drain plug. I found this just as difficult as getting it off. The workshop manual says to use some sort of thread lock: I didn't have any so tried one very thin layer of teflon tape but had to remove it because I was having such difficulty getting the plug to do up.

After about an hour I finally got it on as tightly as I (and my father, combined, yanking on the ratchet) could manage.

For now, do not reassemble the turbo support, front pipes or exhaust in case the drain plug isn't seated properly and you have a leak.

Reinstall radiator and preparing for the new coolant:

1. Place fan shroud on radiator and do up the screw.

2. Reinstall the radiator. Make sure the two rubber mounts on the bottom of the radiator remain in place.

3. Reinstall the coolant reservoir.

4. Reattach the top and bottom radiator hoses, making sure to tighten them sufficiently (but not too much otherwise you will crack the plastic!). Ensure the radiator drain plug is done up.

5. Reattach the lower section of the fan shroud. Give the fan a spin to make sure it doesn't hit anything.

6. Plug in the thermostat sensor wire.

7. Turn the ignition on (but not the engine) and set the heater to max (32 degrees).

Adding the new coolant:

Adding the new coolant is quite a laborious and repetitive task, but extremely important given that air pockets in the coolant system is likely to cause sharp spikes in engine temperature.

If your coolant is pre-mixed you can go ahead. If, like me, your coolant needs to be mixed with water, obviously work out the required proportions and combine (if you don't have a big enough container, do about 2L at a time. Small variations in the mixture won't matter, but try to be accurate).

Below is the procedure described in the R33 workshop manual (its a little clearer than the R32 workshop manual) with my comments/correction/suggestions in []'s:

1. Undo and remove the air release valve. [stupidly I didn't take a picture of this. The release valve is located on the left of the engine (looking from the front of the car), on the front side of intake manifold collector. You will see a little sticker underneath it that says "Never open when hot".]

2. Top up the radiator with coolant at [a] filling speed of less than 2L / min [keep checking under the car -- both near the radiator and near the block drain plug -- to ensure that the coolant isn't spilling out somewhere]. Close the plug if coolant start spouting out from the air release plug while filling up the radiator [i suggest you place a rag underneath the plug, and allow as many air bubble out as possible. Only close the plug when there is a steady stream of coolant flowing out]. Top up coolant to the top.

* Replace air release plug copper washer with a new one. [i didn't bother, but I guess you should ]

3. Close the radiator cap and start the engine. Keep idling until the thermostat injection vale opens.

4. Check that the engine coolant temperature gauge needle is pointing over mid way [this will take 5-10 minutes of idling]. Touch the radiator lower hose and make sure warm water is flowing. [i think they got that the wrong way round: warm water should be flowing through the top radiator pipe]

5. After checking the thermostat injection valve, race the engine 2 to 3 times with 10 [second intervals at 2500RPM between each race].

CAUTION: Do not raise the engine coolant temperature too high.

6. Stop the engine.

7. After cooling down the engine [this will take 30-60mins each time ], open the radiator cap and check the level of coolant. If the coolant level has decreased repeat the steps from 2. [i had to redo this process about four times over about 90 minutes]

8. Once the coolant level has stabilised, top up the coolant to the MAX line [printed on the inside of the radiator filler hole].

9. Refill the coolant to the filler tube. [Replace] the radiator cap and stop the engine [the engine shouldn't be on anyway, so I have NFI what they mean]

10. After cooling down the engine, refill the reservoir tank with coolant to the MAX line.

11. Restart the engine and increase the engine speed to 3000 rpm from the idling position. At this time make sure there is no heater core water flowing sound from the instrument panel area [i think they are referring to the center console area]. If there is a water flowing sound, repeat steps 2 to 10 until the coolant level stabilises.

As I noted, I had to 'top up --> turn on car --> race engine --> cool down car' about four times before the levels stabilised. Be careful when opening the radiator cap after cooling the car: the coolant can be surprisingly hot.

[lwells]

Assuming everything is A-OK...

Reinstall exhaust:

As I noted above, you should get your hands on appropriate gaskets so you can replace them at this stage. Unfortunately for me, that wasn't possible. Instead I cleaned up the existing gaskets with a light sand and applied a thin coat of a quality manifold cement. Lucky for me this seemed to hold (no leaks), but if you plan in advance get the gaskets...

1. Replace gaskets on the turbo dump pipes and cat.

2. Reinstall the rear turbo support bar: do up the nuts at either end then the middle nut that holds the turbo line.

3. Reinstall the front pipes by attaching them to the dump pipes. Place the nuts on the thread, and do them up a turn or two so that they grab and hold but still give you plenty of wiggle room.

4. Attach the cat end of the dump pipe to the rear exhaust section: you will need to wiggle things around to get them in place. Put the nuts on the threads, but don't do up very tightly.

5. Do up the nuts on the turbo dump --> front pipe flanges. Try to get a nice flush fit by torquing each bolt a bit at a time (like you would when torquing down a head, for instance), doing a couple of circuits before a final tighten.

6. Do up the nuts on the cat --> rear exhaust flange. Again, try and get a nice flush fit.

7. Place the exhaust back on the bracket (just in front of the cat, on the drivers side) and tighten bolts (you want these suckers tight to stop the exhaust rattling).

8. Replace cat shield. Do it up tightly, otherwise it will rattle like a mofo (very irritating!).

Conclusion

All done! Now just sit back and wonder where the hell your weekend just went!

Some other observations:

1. I didn't bother replacing my thermostat as it seemed to be working fine. If you have any doubts though, during the radiator removal is the best time to check and if necessary replace it. PranK's guide contains instruction on how to remove the themostat.

2. Unless your exhaust is stainless steel, tiny bits of rust will fall everywhere. Wear some protective glasses, or be prepared to spend 20 minutes removing rust from your eyes (like me ).

Cheers,

Lucien.

[lwells]

Fixed the photos. Will try and fix some of the remaining broken links and reformat a bit when time permits

[cowie165]

Lucien I can relate to the rust particles in your eyes... I changed the front pipes a few months ago (btw wish I had read your thread first and done radiator at the same time) and took a few trips to the sink to wash the crap out of my eyes - and that was with safety glasses on too

Awesome thread, very easy to read. Great work.

[Duncan]

Great tutorial!

If you have trouble with removing the cat temp sensor in the future, you can undo the plug end instead, it is under the passenger seat just remove it through the floor.

[markimak]

when doin my GTR turbos i lost all my coolant and most of it in my head cause the turbos are lower. so i used genuine nissan coolant. 2L a little water. ther is a bleed screw next to the fuel rail on Rb26 i dnt knw if u coverd that. its imprtant to unscrew that to let air out.

mark. GTR engines run very very hot under the bonnet fresh effective coolant is essential

[lwells]

ther is a bleed screw next to the fuel rail on Rb26 i dnt knw if u coverd that. its imprtant to unscrew that to let air out.

Yup, I did. Its called the "air release valve".

[lwells]

Okie dokies. Another day, another fix of this thread Pictures should all be working now.

[SKiTLz]

Most of that should be the same principal on an RB20. Im going to attempt mine next weekend. Hopefully things aren't quite as difficult to get to as the RB26 as it sounds like you had some real fun.

[Ryanr32]

This may be cutting corners.....

but rather than looking for the drain plug and so forth,

run a flush through the engine first, drain at the radiator, remove the hose to the engine, grab the good old gardon hose and hold it tight at the water inlet manifold so as to ensure little air gets in. Run the engine for 30 seconds untill all the crap is washed out, get someone to keep an eye on the coolant temperature on the dash.

I know its water restrictions, but if mechanics are allowed to do it .......

anyway... i've never seen this done on a gtr, but ive seen it on many other cars so... maybe for some reason you cant do it..

Let me know what you guys think..

[Ryanr32]

forgot to write... prior to flushing the crap out... undo the lower radiator hose to the engine, but im sure you guys worked that out.

[Ryanr32]

oh and lucien,

i think the reason you check the lower radiator hose for warmth, is to check that the thermostat has opened letting the coolant run around the engine.....

[Mid_Nite_R33]

This may be cutting corners.....

but rather than looking for the drain plug and so forth,

run a flush through the engine first, drain at the radiator, remove the hose to the engine, grab the good old gardon hose and hold it tight at the water inlet manifold so as to ensure little air gets in. Run the engine for 30 seconds untill all the crap is washed out, get someone to keep an eye on the coolant temperature on the dash.

I know its water restrictions, but if mechanics are allowed to do it .......

anyway... i've never seen this done on a gtr, but ive seen it on many other cars so... maybe for some reason you cant do it..

Let me know what you guys think..

so simply disconnect bottom and top radiator hoses and stick a garden hose into the engine where the top radiator hose connects? with the motor off or on ?

cheers

[CrimsonLey]

^^

LOL, I'm about to try this today with a garden hose to flush the rust out of the block. I'm buying A LOT of distilled water at the Supermarket to ensure that I flush the tap water out afterwards.

[rofocale]

"I see you have constructed a new socket wrench. Your skills are complete. Indeed you are powerful... "

[Monkey.Magic]

Nice!

[BuuBox]

Thanks for the guide, very useful.