NSX Radiator problem

[mart155]

Out for a drive on Sunday night and my radiator decided to dump all the coolant. :(
I haven't removed the old one yet but it looks like I need a new one. Bad news is that Honda want £880 for a new one and they won't be able to get it until November.

Searching on Google, I found a company called Mishimoto UK who have what they call a performance radiator for the NSX which is a direct OEM fit for £235 + VAT.
Does anyone know anything about them or have fitted one of these. Are they any good?

I would be grateful for any advice or recommendations as I don't really want to wait until November.
Also, I am planning to do the work myself so any advice about the coolant I should use and the bleeding process when refilling would also be welcome as I understand it isn't as simple as just refilling.
Thanks
Martin.

[NSXGB]

Hi Mart,

Have a little search for Mishimoto or Koyo rad on here. They are more or less the same but when installing the Mishimoto you may need to make a small modification to the radiator shroud. The Koyo rad is a straight swap.

[britlude]

Check ebay/amazon too as there's huge price differentials for the same item.....

[Kaz-kzukNA1]

Hi, Martin.

Please inspect your radiator and coolant hoses first because you may have split/burst hose.

Most of the time, the OEM radiator will crack at the bottom right side of the tank near the lower hose neck. OEM radiator is made from recycled aluminium cramped to the plastic tank at the bottom and top.
Two different materials with different expansion/contraction rate and going through huge thermal shock frequently especially at the lower side (NSX is different from other production cars, the hot coolant enters from the bottom side) and thus, sooner or later, it will start leaking or the plastic tank will crack.
This is the reason why I mentioned many times on here that the OEM radiator is a consumable parts and must be replaced at regular interval.
Hope you caught the issue without cooking the engine.....


I would recommend Koyo Radiator over Mishimoto one for the direct fitting and welding quality.
The only downside is that Koyo rad is stocked in US so it will take about two weeks for the delivery after placing the order.
I have already ordered and installed Koyo rad for many owners and in fact, I'm going to receive another delivery of Koyo rad tomorrow.

Please refer to the following link for some of the examples.
http://www.nsxcb.co.uk/blog.php?1811-Kaz-kzukNA1&s=&tag=koyo


I think our member 'mutley' installed the Mishimoto one on his NSX as he also experienced the crack (possibly your issue is also cracked tank???) and I also inspected the fitting on the NSX.
You will need to cut part of the plastic shroud in order to fit the Mishimoto one but not a huge task so if time is the highest priority, you may want to go for it.


The Koyo rad is 36mm thick whereas OEM one is 32mm so you will need bit extra coolant but not much.

For the coolant, just visit your local Honda garage and ask for the 5L bottle of Honda Type 2 coolant.
08CLA-G01-8L0 x 3 or 4. About GBP19 each inc.VAT but you may be able to get NSXCB discount.

For C30A 3.0L engine, you will need at least 16.5L plus extra for bleeding and also for extra capacity of Koyo rad.
Each 5L bottle of Honda Type 2 coolant comes with bit extra amount and it contains just about 5.45 – 5.50L.

I think Honda may have 1L bottle of Type 2 coolant but I have never bought one so not sure about the parts no..

Also, please make sure to buy the blue one using the above parts no..
I know Honda used to sell green coloured coolant in blue bottle so bit confusing....
Type 2 coolant is blue.
When you visit the Honda garage for placing the order for the coolant, they may have some left over of new coolant used for another car so you may want to ask the parts manager for the special deal on that if you feel the need for the extra fluid.


You don't want to mix the old and new coolant especially, if your existing coolant is green one. It may create black flake like particles.
Ideally, you should rinse the system with soft water first and then drain as much water as possible before re-filling the system.

By the way, if your washer motor is dead, now is the best time to deal with it as you will have extra room while the radiator is out. It can be done with the radiator in place but bit tricky on removing the old motor if it was stuck in the tank.


Also, I strongly recommend replacing the upper and lower rad hoses as the hose neck shape between Koyo rad and OEM one is slightly different that you want to put the hose cramp bit inwards when using Koyo rad.
If re-using the existing hoses and cramps, you may want to consider using double cramp per neck as you must place the cramp at the same position on the old hose.

In fact, if your coolant header tank, tank cap, all of the hoses, cramps, thermostat were not replaced within the last 10 years (presuming you don't have aftermarket header/exhaust box, etc that generates extra heat), now is the best time to replace all of them. It will help draining extra old coolant as well.


Regardless of the extra tasks above, you will need to drain the old coolant from the F & R Eng block and centre floor pipes so you will need at least 2 x 8mm aluminium packing.
90471-580-000 x 2.


If you have never done this before, it is better to get 4 bottles of above Type 2 coolant because you will struggle to bleed the air.


Through out the process, please set the A/C CCU at 32degC setting before removing the IG key or disconnecting the battery. If you forgot, just remove the air mix motor cable from the water valve and just manually fully open the valve. That's what I normally do when servicing the cooling system while the A/C CCU is removed from the car.
You will need to remove the water valve any way if you are replacing all of the coolant hoses.


Just follow the workshop manual for the bleeding procedure.
I use different procedure as I use vacuum fill equipment but it's almost the same.
Once you have carried out the initial bleeding before starting the engine for the first time with the header tank cap partially closed (about 45deg, first stop from full open, as in the workshop manual), I normally run the engine for about 30sec to 1min just to push any remaining air pockets in the system towards the front of the car. Never run the engine any longer than this.

The thermostat is closed (strictly speaking, there is tiny pin opening at the top of the thermostat so there will be minute flow) so the only coolant flow is inside the engine and the heater circuit (thus, you must keep the water valve in fully open position) and by running the engine for just short period will allow the remaining air to be trapped at the bleeding point at the heater core.

Bleed the air again and then follow the manual to properly warm up the engine with the header tank cap partially closed at 45deg.
Cool down the system, top up the coolant, double check no air at the heater core as well as at the radiaotor then go out for the test driving session.
Leave the car overnight, double check no air at the heater core and radiator and final adjustment of the coolant level.

Not simple so just take your time......


Kaz

[drmikey]

I have a brand new and boxed Mishimoto Rad I can do for £235 delivered ;)

[mart155]

Thanks for the replies everyone.
Mike,, I would like to take you up on your offer. Let me know how you want to do it.

[mart155]

Kaz, once again, thank you for the detailed description, it will be invaluable when I am doing the job.
Do you think it is worth me changing the thermostat as well?
If so, do you know what the part no. is and also for the rad hoses.
Thanks

[Kaz-kzukNA1]

Hi, Martin.

If not replaced in the past, best to do it when you have empty cooling system.
Or, you can do it at the time of TB/WP service as you will need to drain the coolant again.

Please note that Honda Type 2 coolant should be replaced every 5 years but from my past experience,
you may want to do it at earlier stage especially if you are flushing the system with the softwater and
not replacing all of the coolant hoses or if this is the first time using the Type 2 coolant.


It's quicker for me to just cut and paste my old post and modify it to suit your NSX spec.

The thermostat and two rad coolant hoses are highlighted in blue below.
Addition to these, you may want to replace the hose cramps at the upper/lower rad hose.
It's the big cramp highligthed in blue below.

I'll just keep the entire list rather than extracting a few parts no. just for your case as
other owners with the same spec NSX may consider overhauling their cooling system.
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++++++++++++++++++++

For RHD, NA1, MT, non-DBW model without modification, I will be using the following parts during my cooling system OH.

*** Radiator ***
(Koyo Rad, V2032)
(bolts for cooling fan shroud)
(spare rubber seal from Mazda/Toyota)

*** Coolant Hose, RHD, NA1, MT, non-DBW***
19103-PR7-A00 x 1
19104-PR7-A00 x 1
19107-PR7-A00 x 1
19501-PR7-000 x 1 Rad hose, lower
19502-PBY-R00 x 1 Rad hose, upper
19506-PR7-A01 x 1
19507-PR7-A01 x 1
19518-PR7-A00 x 1
19519-PR7-A00 x 1
79721-SL0-010 x 1
79722-SL0-A00 x 1
79725-SL0-A00 x 1
79726-SL0-000 x 1
79727-SL0-A00 x 1
79728-SL0-A00 x 1
19422-PR7-A01 x 1
19423-PR7-A00 x 1
19424-PR7-A00 x 1
19522-PR7-A00 x 1
19523-PR7-A00 x 1
19524-PR7-A00 x 2
19526-PR7-A00 x 1

*** Figure of ‘8’, rad drain/bleeder o-ring, aluminium gasket ***
91318-PY3-000 x 1 figure of '8'
19012-PD2-004 x 2 rad drain/bleeder o-ring (not required for Koyo rad)
90471-580-000 x 2 aluminium 8mm gasket

*** Cap, header tank, thermostat ***
19045-PR7-J24 x 1 tank cap
19101-PR7-A02 x 1 header tank
19301-P8E-A10 x 1 thermostat

*** coolant hose cramp ***
Some can be re-used if you know the original condition.
If not, replace them.
Not worth the risk.

19511-PR7-A01 x 12　　big one (if replacing just the upper/lower rad hoses, then you just need 4 in total)
19512-PC6-003 x 2　　　low tension, header tank
19513-PE0-003 x 12　　high tension
90661-SL0-A01 x 6　　　pre-set type
95002-4125004 x 12　　 small one
95002-70000 x 1　　　　 overflow tube

*** Honda Type-2 coolant ***
08CLA-G01-8L0 x 3 or 4
Please refer to my previous post above regarding the capacity, etc.


*** lots of silicone/rubber grease + time ***


Again, please note that above list is only for RHD, NA1, MT, non-DBW without modification.
The parts number, the number of each hose, number of hose cramp, etc are different for other spec such as the year model, RHD/LHD, MT/AT, aftermarket parts, etc.

If you have the aftermarket parts, removed the engine bay cover, etc, some of the parts in the above list won’t be suitable for the purpose without the extra parts/protection/process.

Kaz

[mart155]

Thanks Kaz, you're a star

[mart155]

Thanks to Mike at R Motion for the Mishimoto Radiator and the quick service.
The radiator arrived on Friday and is now in the car. I haven't yet filled the system up with coolant yet though. My upper brackets were looking a bit shabby and had started to show signs of rust so I have cleaned them up and painted them gloss black. Once the paint has completely dried I will finish the job.
My original rad was completely gone for about 200mm along the centre of the inside edge at the bottom where it meets the core.

The modifications people have mentioned were not too difficult and consist of removing come of the plastic on the fan cowling where both hoses fit onto the radiatior. I just marked where this was and used a small grinding wheel in a drill which was exactly the right size for the job. I also had to slightly modify one of the lower mounting holes on the cowling as it didn't quite line up with the hole on the radiator. This was done using an angle grinder.

The Mishimoto rad was extremely well packed and overall I was quite happy with the quality. Sure the welds could have been a bit neater but overall it looks pretty good and certainly better than paying the £870 for a Honda replacement.

[mutley]

HI Martin,

I'm glad you got everything sorted, I forgot about the other minor mods as it was long ago and, as you now know, didn't take that long to rectify. Filling and bleeding doesn't take that long either so you will be back on the road in no time.

Cheers

Jim

[goldnsx]

Just follow the workshop manual for the bleeding procedure.
I use different procedure as I use vacuum fill equipment but it's almost the same.
Once you have carried out the initial bleeding before starting the engine for the first time with the header tank cap partially closed (about 45deg, first stop from full open, as in the workshop manual), I normally run the engine for about 30sec to 1min just to push any remaining air pockets in the system towards the front of the car. Never run the engine any longer than this.

The thermostat is closed (strictly speaking, there is tiny pin opening at the top of the thermostat so there will be minute flow) so the only coolant flow is inside the engine and the heater circuit (thus, you must keep the water valve in fully open position) and by running the engine for just short period will allow the remaining air to be trapped at the bleeding point at the heater core.

Bleed the air again and then follow the manual to properly warm up the engine with the header tank cap partially closed at 45deg.
Cool down the system, top up the coolant, double check no air at the heater core as well as at the radiaotor then go out for the test driving session.
Leave the car overnight, double check no air at the heater core and radiator and final adjustment of the coolant level.

Not simple so just take your time......

Kaz
I was flushing the coolant yesterday and went through the SM procedure of bleeding it, plus Kaz's tips above. I did this about 5 times and always got a little bit of air out at the heater core. I took 13 l out and initially 11l in while the coolant tank was at 2/3. As I warmed the car up and watched the coolant tank and waited for the fan to come on the temp gauge went one line above the normal position (was absolutely horizontal). By that time I shut the engine off. With the IGN ON again the coolant fan was running its first time and at MAX. During that time the long awaited significant drop of coolant in the bottle happened. The coolant at the hottest of the three hoses (heater?) was 82-83 deg. C. The other ones were cooler. I'll let the engine cool down, recheck for air in the system and redo the procedure once again.

Kind of a tricky procedure...