Eng Refresh + ABS Upgrade 202504

[Kaz-kzukNA1]

As in the recent post, started servicing another NSX.
This is the 1st of the 3 NSX with the same service menu for the efficiency and finger sensitivity purpose.

Big thank you to the owner with the cooling system service letting this owner being served first.
I would have done the same.





Tried to capture the intermittent [BRAKE LAMP] warning but obviously, it won't happen when I wanted.

It happened just when I wanted to take the car out of the garage.

By the time I went back inside the garage to get the tool to hold the brake pedal, no longer be able to reproduce the same issue.

The owner is already aware of this and on the way to my place, confirmed by his friend driving behind in the 2nd car that it was genuinely caused by the partially dead lightbulb or socket.
He noticed that from time to time, one of the brake lightbulb at the left side didn.t work.

The gauge cluster was already refurbished by me years ago and the warning only triggered after pressing on the brake pedal so not the gauge cluster issue.

I will probably replace all 4 brake lightbulbs (JDM) on this occasion.




Hope it's nothing to do with several extra wires running behind the carpet inside the boot….






The owner told me that he re-charged the a/c refrigerant twice but only lasted few days.

And the a/c specialist was someone following the rule.

He told the owner that he would not be able to charge the system if there was obvious leakage detected.

And it was already re-charged twice yet the owner told me that it only lasted few days.

So, connected the manifold gauge and somewhat expected, it was completely empty.

From all the info I have, I suspect it's leaking from the compressor seal or the schrador valve.

If the refrigerant escaped within few days and with such huge leakage, the specialist would have detected so very unlikely to be damaged pipe or fitting o-ring issue.

Still, I'll give a good look.




Wanted to carry out the vacuum check but must replace this hose gasket first.
(The red panel is my tool box, not the body work.)

Didn't like how it looked and ran out of the new one but easily found verywhere.

I must have overtighten the fitting last time.


Very unlikely but just hope the leakage is not happening at the evaporator.

It happened on my NSX.

Whole dashboard must come out from the cabin.

As I need removing the blower fan motor for the ABS Upgrade, I'll first start with the inspection of the evaporator.

As a side note, it's important to use the A/C regularly to oil the seal and o-ring around the system.

The oil travels throughout the system via refrigerant and that's why when you have system leakage, you will lose the compressor oil as well.

If the compressor was not engaged for months/years, the refrigerant will escape from the compressor front/rear seals.




Just like this one.

With the same photo, tried showing that it still has the original WP but not great camera angle.

[Kaz-kzukNA1]

This is something new.

The aluminium crimped section of the radiator upper tank is opening and seeping the coolant.

Not enough to cause even a single drip on the floor though.




Not sure when was the last time the coolant level was adjusted but it was above the Min but not at the Max level.

On NSX, coolant enters from the bottom side of the radiator so normally, you would see this crimp opening at the bottom tank.

Also, seen many hose neck getting cracked for the same reason at the bottom side.

Not enough sample but I have never seen one with upper neck being cracked.


Will speak to the owner to replace the radiator.

Hope Koyo one is in stock and it is my policy not to re-use the upper and lower rad hose on the aluminium radiator so new ones required.




Already in the plan but to remind other owners.

Please never use non-WPC method for any wiring that could face the high humidity.

This is the rear O2 sensor connector and already seen patina corrosion in the past.

It will harden the wires and eventually, breaks off.

Unfortunately someone chopped off the OEM connector so must be repaired.





Not great camera angle but wanted to show the state of the oil cooler top hat.

Very rusty and quite rare but already seen eng oil leakage from here.

I think it's already discontinued so I'll chemical treat it later.





Will check the alignment around this area.

I would say too close each other.



Compression test, initial test driving, further Health Check to follow before starting with the ABS Upgrade and evaporator inspection.

More to follow later.


Kaz

[Kaz-kzukNA1]

Lots to be done under several different time zones over the next few days/weeks.
For now, just a quick update.


1. Must replace the Radiator

Koyo Racing Rad - used to be much cheaper.
Now, the latest retail price is about £400.
Checked price in US inc. delivery/tax to UK but no longer cost effective.
Back ordered at several venders but in stock at certain places in UK.

It's my policy not to re-use the upper and lower hoses when installing the all aluminium radiator.
Must place new order to Japan.
Hose clamp can be re-used if not rusty.

Koyo rad should be quick delivery if in stock but not the coolant hoses.




Will leave the installation of the ABS modulator and the tri-pod until after the new radiator in place.

Carrying on with the installation of the new brake pipes, ABS upgrade loom and the removal of the classic ABS controller.
However, out of focus but what are all these wires behind/below the glove box….

Looked to be the dealer option OEM Keyless Entry System connected to the Security brain.
I have the same system on my NSX but installed it by myself.
Don't remember so many wires….
Though, it was more than 30 years ago….

[Kaz-kzukNA1]

Based on all the testing carried out by myself, can now confirm the refresh procedure.

There is definitely a leak.
However, it can only be detected using the dediated vacuum gauge and not by the ordincary 2 dial manifold gauge.

Haven’t checked with the owner but most likely, the a/c specialist didn't have the standalone vacuum gauge.

With the ordinary gauge, this type of leakage can’t be detected under vacuum unless pressurised.

Looking at the state of the compressor area, will first replace many o-rings and the compressor.


The drier/receiver is a must whenever disturbing the a/c system.


Addition to these, will replace 2 x front a/c pipes but it all depends on the state of the fitting.

Quite often, some of them are seized at the R & L condensers.

The Exp. valve will be replaced but again, the fitting could be seized.

Even with the use of double spanner, it can kink the aluminium pipe so unless replacing the evaporator, forced to leave as is.


So, in summay, first, deal with the o-ring, compressor and the 2 pipes + drier/receiver.

If still leaking and the fittings seized at the R&L condensers, replace the condenser+pipe as a set.

I hate this as it requires the removal of the front bumper.

Replacing the evaporator is not in the scope at this stage.

Though, if the fitting at the exp. valve seized and still leakage detected, may be forced to do so.

[Kaz-kzukNA1]

After starting the engine several times and confirmed that the radiator top tank is still stable, went out for base line test driving session.

This NSX has aftermarket damper at the front with the OEM spring.

Rear set is all OEM.

The tyre is fairly new and using the Advan V701 Fleva on OEM 16/17 wheels.

Never used this tyre on my NSX so used my standard tyre pressure setup.

Only very gentle driving and don't know what alignment setup the owner is using but compared to my poor Type-S damper/spring with near the end of tread life Neova AD08RS, quite liked it.

Bites into the road surface nicely and while bit too soft feeling on the side shoulder, in return, very comfortable on the terrible road condition around my area.


I did find inconsistent CL bite point after driving for awhile.

When it was cold or while placing the car on the lift that requires the delicate CL operation, no problem.

It’s just once the car gets warm.

I know this owner and he is a experienced Racing driver.

Knows how the CL works and won't slip the friction discs massively at the bite point.

Normally, it's the other way round with the worn out friction disc.

When cold, easy to detect that the CL is slipping.

When it gets hot enough, the friction co-efficient increases and no more slip.

Having said this, not the same once the CL material gets really worn out.

Thus, opposite to what I felt on this NSX.


On the Cl Hyd Sys, this NSX has dumper-less joint with the NSX-R CL pedal.

I installed them for the owner many years ago.

At that time, no such CL feeling.

Since then, the owner only covered just over 2K miles so very little mileage added.

Felt more like release bearing not sliding smoothly over the metal guide.

Or, too much rust on the CL material.




Double checked the CL pedal mechanical rattle and the free play adjustment.

All good and consistent with mine.

I have the same setup (damper-less joint + NSX-R CL pedal with specific pedal adjustment for the NSX-R).

When hand operated, felt no air trapped.

May bleed the system for testing purpose.


For now, no plan of replacing the CL and want the owner to drive regularly to observe the situation.


Wind noise from the door window area.



For the next few days, must focus on the Gauge Cluster calibration process so no further activity on the mechanical side on this NSX.

Will release the updates on the gauge cluster service shortly.


Kaz