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Today at Atelier Kaz - Private NSX Enthusiast, ex-Honda R&D engineer with F1, Indy/CART background

Radiator – emergency swap 01

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Although I mentioned this like more than 100 times here, it seems that my message is not getting through to the owners...



So, one more time.....




Please replace your radiator regularly.




It's a consumable parts like brake pads, disc, etc. OEM one is using plastic tank at the top and bottom crimped by the aluminium core. Two different material going through massive thermal shock every time when you drive the car so sooner or later, the plastic tank will crack or the crimped section will start to open and weaken the seal between the aluminium core and the tank resulting in slow seepage.



Also, the fins at the front lower half of the radiator are already smashed and blocked by now that your cooling efficiency is very low compared to the fresh condition. May be fine for C30A engine but big no-no for C32B engine.
Even without any engine modification or well looked after NA2 NSX, I saw temperature gauge going upwards on C32B when driven hard during the hot humid summer in Japan.





For this NSX, I recommended to replace the radiator in the past but it was left for a while.
Then, after several months, I got a message from the owner that he started to see some coolant dripping on the garage floor.
So, placed another order for the Koyo radiator in US (not sure why I can't order it from Japan....) and just recently had the delivery so emergency swap was arranged as I just had small window before overhauling the drive shaft on the other NSX just went back for pressing out the seized joint inside the hub.




Last time when I saw it, it was just showing the trace of blue marking so I diagnosed it as potential slow leakage.

Now, it's obvious that it's seeping and making the area wet. The crimped section has opened up and the seal is broken between the aluminium core and the lower plastic tank. Typical for the NSX cooling system as the hot coolant enters from the bottom side on our NSX.





Having fun loosening these bolts. No need to completely remvoe them as the shroud stay has slit on itself so you just need to make a few mm gap to slide it up but still, some challenge.
Much easier if I can break it off.





The old radiator removed and gave some cleaning around the area.
Tried to rinse off the leaked coolant as much as possible as the air flow while driving the car carried some of the coolant towards the spare wheel bottom holder area.

I couldn't rinse off some of the coolant as it was trapped between the two panels just below the radiator.

The owner may see blue fluid under the car every time when the car gets wet but since I'll carry out vacuum leak check of the system before re-filling the coolant, rest assured that it's not leaking from the radiator and it's the trace of old leaked coolant trapped in the channel of the panel.


Also, I use blue washer fluid and when the car gets warmed up, it could seep out from the tiny hole in the middle of washer tank cap.



Aiming to return the car tonight so better be quick.
I have so many emails to reply but will do that after finishing this task.



Kaz

Comments

  1. pralognan's Avatar
    All OEM radiator manufacturers use glass filled nylon header tanks crimped onto brazed aluminium cores for production runs of more than about 1000pa by agreement with vehicle manufacturers for reasons of value. Small production cars use all aluminium welded construction or use an existing plastic tank from another vehicle!
    Our durability test was 70,000 cycles from 0 to 2.5 bar at 130C for a batch taken from production,consistency over a group of Xbar minus 2sigma.
    The hope was that this test would equate to a vehicle life of about 20 years,or at least to a time when other parts like engine would need a rebuild.
    Today all heavy trucks,farm tractors and construction equipment use plastic tank radiators as OEM. Part of our replace not repair society!
    By the way,why do NSX nuts and bolts rust so badly?