Radiator Refurbishment

[Formula 91]

Hi, The radiator on my car has developed a very slight leak . Should I buy an aftemarket radiator or has anybody had their radiator refurbished ? If so, where did they have the work carried out ?

[NSXGB]

Koyo all the way.

[Senninha]

As above, direct replacement to OEM install as shown …

[PeterW]

Yes, I got a Koyo.

[Formula 91]

Looks like an aluminium radiator is the way to go. Do I need to purchase any other parts apart from new hoses and clamps. Where is the best place to purchase a Koyo radiator?

[FlyNavy]

You'll probably not beat a Black Friday deal at Torque GT:

https://www.torque-gt.co.uk/koyo-performance-aluminium-radiator-nsx.html

I certainly couldn't find cheaper when I purchased this time last year

[sorepaws]

Looks like an aluminium radiator is the way to go. Do I need to purchase any other parts apart from new hoses and clamps. Where is the best place to purchase a Koyo radiator?

Direct replacement - also includes new 10mm fixings. At the price in the previous post its a steal.

[lotusolly]

You'll probably not beat a Black Friday deal at Torque GT:

https://www.torque-gt.co.uk/koyo-performance-aluminium-radiator-nsx.html

I certainly couldn't find cheaper when I purchased this time last year

Thanks for the heads up

Ordered :)

[Formula 91]

Hi, i have been on the forum and noted that a rubber seal from Toyota/Mazda is required for the radiator replacement . Does anybody know the part number ? Is a new drain plug also required from Koyo ?

[NSXGB]

I've installed a KOYO rad in mine. I don't know what seal you are referring to. The new rad comes with the drain plug and the rubber seal required for it.

[Kaz-kzukNA1]

As NSXGB mentioned, the Koyo Rad would be delivered with the bottom/upper plugs with the rubber seal installed on each of them.
Also, there should be 4 x bolt attached to the rad body for holding the rad fan shroud.

Once received, please flush the radiator well.

Based on the feedback seen on here and on Prime, you may want laying it flat, fill it up with water and leave it to monitor for tiny seepage around the welding.

Never experienced after installing so many of them but recent feedback on Prime suggests potential welding issue causing tiny seepage but not all of them.


Kaz

[Formula 91]

Hi, It was in a post by Kaz in 2014 (Radiator Problem) showing the parts required for installing a new radiator. I think it may be required for the fan shroud.

[Formula 91]

Hi Kaz , I hope you can help with the Toyota /Mazda part number for the spare rubber seal mentioned in the previous thread from 2014.

[Kaz-kzukNA1]

Placing the highest priority on another subject until the end of February so slow to respond.
Please bear with me.

If you really want, you can get the Mazda NF01-15-203 but as stated above, no need.

You can re-use the Koyo rubber gasket at least once.

The comment from 10 years ago about the spare gasket was based on the initial experience that was even before that.



https://lh3.googleusercontent.com/pw/ABLVV86cMc5UPR-cMuJ4O3Y9lX76h9jy4GviYnLR-Ea-L1fXbdVEpqyF7ZscwsmyaFh7U2eqiSXhdlLw3RjLsR4mYYFSaj Yvf4J4XSYl5thwswDwHbfmT_VM_7YiJJGzFbwJlepB4kTtCB9E yB7JuO1vaxtODQ=w1080-h810-s-no?authuser=0

https://lh3.googleusercontent.com/pw/ABLVV85rNi3RDZ6aoOWRZjfCxwueV6Z3j8CQEtH6mXN34v3V-JCcxYQRxWAlYkE82AKuF0k0Kh57KQyJ61oDZ_--j1CRtvZQ-d25Opzdvxlc7O6Z4VhEqCKCpptw0XIArfz_vjzs83blaN-AkGbWMSVPOjDxOQ=w1080-h810-s-no?authuser=0
Didn't like how the gasket sat at the mating surface of the radiator drain port because of the drain plug design.

Since then, don't know whether Koyo changed the material, the thickness, etc or may be it was one off unlucky at that time but for all the ones afterwards,
no problem even with the same plug design.



https://lh3.googleusercontent.com/pw/ABLVV84MIhAvybFoL6_bWT24sIQc6Sw4iK9cqYCL8k89w2LTcf 7nONkZi_-i9OTGDcA-sNZ76BU8tZjGDxOWqagFDneoOoy3dybzBfs0qfbDIxeIkxCYpK BFjJsRojTE0hbOL5bt2OmrdDtrvLgwBxi8lY8nlA=w1080-h810-s-no?authuser=0

https://lh3.googleusercontent.com/pw/ABLVV87_n993Ldr1VA5AjQo6xENbFSUrjR4uORgkFCIeNmMMQG JLbHChingh0CuQL_s2KgefvovfY1QsB8Y_QrgK0LL_RWr6Vt4X 2EDRvwnQu4tb9kUOeNSDTmOEzLYTrO3mMYmi_frLd7IyHqdAbc NNwOpSeQ=w1080-h810-s-no?authuser=0
The Mazda parts consists of not just the flat rubber gasket but also the plastic drain plug.

Quite cheap in Japan and even several good quality aftermarket ones available.

However, probably around £10 in UK just for a single drain plug.

Although the Mazda plug looked to be the same diameter/pitch as the Koyo one, it's much shorter.

Also, the plug body is plastic whereas the Koyo one is machined aluminium.


I own MX-5 and change coolant every 2 years.
In old days, used to create own coolant mixture at 30% and change it at short interval.
I still prefer 30% from the cooling performance point of view.

If you own MX-5 or other JDM (Mazda/Toyota/Nissan/etc) using the same plug,
you’ll know the #3 slot on the plastic drain plug could get damaged.

So make sense to replace the plug and the gasket as a set every time.


As mentioned above, Koyo drain plug is machined metal.

If changing the coolant frequently, just replace the gasket when required.

Look for the M10 flat rubber seal.

From what you wrote so far, you either have the Koyo Rad ready to be installed or about to get one.
You can measure the one pre-installed on yours but this is what I have.

Should be the same unless Koyo changed the design spec recently.

ID: 10mm, OD: 16-17mm, THK: 2mm



https://lh3.googleusercontent.com/pw/ABLVV86Sk8tl303huq7I7MSwxzbCQfoDKB3N3MnglYZVDheejo hM46kx8i4KjQp6B6Qa5RnputXdl5rpIEHt3L5hEJkZWe7p61oV ORIRVQWZzx_vzYrMj6LiwWDFzqZOVfF5SU6shbAfMLigIRLy2N 6Mg_M_xA=w1080-h810-s-no?authuser=0
The flat gasket of the Mazda one is thicker (2.5-3mm) than the Koyo one.

My preference is THK 3mm.


Don’t know what material in use for the cheap ones on the market but you can find the EPDM one as well.

If not sure, just replace it every time when you drain the coolant.

Plenty of M10 flat rubber gasket on the market with all sorts of different spec.


It's in contact with the coolant chemical passing through the threaded section of the drain port, thermal shock, all sorts of debris, etc so you can get some idea on the environment.


Again, you can re-use the Koyo rubber gasket at least for the next service.


Don't know if it will fit and not sure of the material but the rubber seal at the TB tensioner adjuster bolt could be similar size.


Kaz

[Formula 91]

Thanks Kaz for clarifying the seal required at the drain plug.