Stock or aftermarket radiator?

Albert86

Albert86

Experienced Member
Joined
18 November 2011
Messages
441
Location
Falcon Heights, MN - no Falcons - no Heights
My car is a 94 and I am progressively trying to get is refreshed.
Last winter I did spool valve gaskets, pan gasket, and full brake caliper rebuild, SS brake lines - plus headers.
This winter I plan on replacing all hoses and thought I would do the radiator at the same time.
(I also am doing harmonic balancer/belts/plugs/cam seals and valve cover gaskets, and plan to flush the ABS - TB/WP is up to date)
I have yet to track my car - may - but is not a priority.
With 72Km on the car should I replace the radiator?
I plan on driving to NSXPO next year from MN to CA.
If I should replace - should I go stock ~ $400 or go with a Koyo ~ $365 or Mishimoto $tbd - or (your recommendation here) ...
Sounds like Koyo fit the best next to stock ....

Thanks for any thoughts (and what else I should be doing) - Al
 
I have a koyo just waiting to drop in. I picked it over other brands because it reportedly fits the best plus Kaz recommends it.

You can get them around $365 shipped.
 
Well if Kaz says so ... It might just be the one.
Did you order new rubber bushings?
74173-SJ4-000

<col style="width: 86pt;" width="114"> <tbody>
[TD="width: 114"]74172-SD4-020 [/TD]

</tbody>
2 each - about $10 total?
Already on my buy list.

Thanks for response - Al
 
shawn110975 said:
my OEm radiator started to split so I got a dual pass radiator off ebay for 300 full aluminum not the plastic top versions they sell

then I put a mesh grill in front of it so rocks will not bent the vents so it will literally last as long as the car.
- - - Updated - - -

I think this is the one I got

http://www.ebay.com/itm/Mishimoto-A...Parts_Accessories&hash=item2a4548f06a&vxp=mtr
Click to expand...

Shawn, did you get the track or street version of the rad guard? Have you noticed any increase in engine temps since you started using it? I tried to get one through Dali awhile ago, but had to get a refund through PayPal. What a surprise! Did you get yours at Science of Speed?
 
The stock radiator cooling capacity is sufficient for a stock 3.0, but is not sufficient for the stock 3.2 with heavy track duty. There is a classic Best Motoring video where the NA2 NSX-R overheated after only 5 hard laps with the Drift King driving it. Kaz has mentioned this on his blog- wondering why Honda did not increase cooling capacity for the 3.2. All that said, I have a Koyo on my car. It is all aluminum (no plastic tank glued to the fins) and about 30% greater coolant capacity than OEM. For a normally-aspirated NSX, it is more than enough for any kind of driving. If you have a SC or turbo and track your car, you should think about a bigger option like the Ron Davis, Driving Ambition, PWR (if you can find one) or if you are a baller, the KSP Engineering triple pass. I know Regan was doing some nice work with Masiv as well.

I also bought the Dali "Street" rad shield and it has done a great job keeping my Koyo dent-free and does not affect cooling during street driving. I do remove it for the track though on Shad's recommendation.
 
I have a 1995 NA1 NSX and I found the stock radiator inadequate.

The owner's manual says (about the temperature gauge), "In severe driving conditions, such as very hot weather or a long period of uphill driving, the pointer may rise to the upper white mark" and that is exactly what mine did on long uphill stretches in the summer.

After I put in an Australian-made PWR brand radiator (since discontinued) that's about 50% thicker than OEM, the temperature gauge has never gone above 3/8 no matter what. That includes uphills in Death Valley on summer afternoons with the AC on. Car companies from around the world come to Death Valley to torture test their cars; I've seen camouflaged cars there in the summer.

And even when your coolant temperature gauge is steady at 3/8, the oil temperature varies according to conditions. At freeway speeds the oil temperature is higher in the summer than in the winter. The interesting thing, though, is that with the aftermarket radiator my car's oil doesn't get as hot in the summer as it did with the OEM radiator. I saw about a 10 degree F reduction in oil temperature in summer freeway driving from the better radiator--I mean on fairly level terrain where both radiators maintained coolant temperature at 3/8 on the stock gauge. (I added an oil temperature gauge to the car while I still had the OEM radiator.)

Get a beefier radiator, you won't regret it.
 
it fit like OEM no problems at all, then I went to Home depot and got some aluminum rain gudder gaurd and put it in front of the radiator
so rocks will not bugger up the fins. I check it often and no bends in the fins so my home depot 1.26 gaurd is doing it job

when you get the gaurd you have to flaten out the very top cuz its bent for use with a rain gaurd but its easy
 
Note that the temperature gauge is very insensitive, so the needle stays in the middle over a wide temperature range. Whether running at 6 to 8,000 rpm for an hour or cruising at 50 mph, my gauge reads the same. Never had a problem with the stock radiator.

So, I'm curious. Unless there's a problem, or a '94 radiator is far worse than a '96, why would one change out the original radiator?
 
ftuhy said:
Note that the temperature gauge is very insensitive, so the needle stays in the middle over a wide temperature range.
Click to expand...
The point of a thermostat is to maintain a certain temperature even in varied conditions.

Whether running at 6 to 8,000 rpm for an hour or cruising at 50 mph, my gauge reads the same. Never had a problem with the stock radiator.
Click to expand...
With the stock radiator, my gauge stayed at 3/8 on the flats no matter what too. Long uphills in the summer were another story.

So, I'm curious. Unless there's a problem, or a '94 radiator is far worse than a '96, why would one change out the original radiator?
Click to expand...
Rereading the posting that started this thread, I see there may be no compelling reason to get a new one. If you've been using good coolant and have changed it on schedule your radiator is probably fine inside at 72K miles. My recommendation to get a thicker-than-stock radiator was assuming a decision had already been made to get a new one.
 
We sell both Mishi and Koyo in our shop. I personally have the Mishimoto in my Nsx and if works perfectly fine, same or better than oem. I have not noticed any difference in hot or cold weather. We have great deals on them as well if you are still looking to get one.
 
Wow - Thanks for the feedback.
So I bought my car with 64K - service history was incomplete except for the last owner - TB/WP job had been done plus a few other items
I never knew if the hose change job had been done. Car seems pretty clean - but like I say - incomplete history.
Last year was fun stuff - Prospeed ECU/injectors - rebuilt brakes w/stock pads and painted calipers - Side scoop - wheels/tires - spool valve gaskets - headers.
This winter I thought I would get to the abs (try flush and verification) - I still have an oil leak so valve cover gaskets (maybe paint covers) - cam plugs.
Then the box next to me has short shifter kit and and S stalk - front compliance clamps - ...
But I see that the coolant hose job is something that I should get to. I have no idea what the former owners used for coolant.
I have seen - maybe once or twice - a couple drops of coolant in the front of the car - ordered the gaskets for the drain plugs - but I am deciding I should just do
the entire hose job.
I went to a track event last year and did some ride-a longs .... sure seems fun... so the car may get a visit or two a year to the track next year.
Have repeatedly told a guy I work with I will never need a SC - keep saying that and watching the ads.
I will go to NSXPO next year - father-in-law is in PS - incentive for a 4K drive.
Don't want my sweetheart in the middle of nowhere Nebraska with green stuff under the car.
So all of this says I may as well just replace the radiator too.
Stock one is comparable to the Mishimoto or Koyo as for price - so that's what started this (hope others can glean something from it too).
Thinking now I will go Koyo - but Shawn is making me think 2x on the Mishi.
Not to ignore RYU - I took a brief look for MASiV - but may be more than what I need - unless they are ~$500 - maybe would consider.
Otherwise I need to puchase some driving skill - if someone has some moderately priced and too worn out.
Just trying to make the car better than I got it ...

Again - TIA to all - Al
 
Koyo

Went to the KoyoRad site and plugged in '92 NSX and it came back with "no product found".
Any idea where I can find one to replace OEM radiator in the Koyo brand?

Cheers
nigel
 
Tom239 said:
The point of a thermostat is to maintain a certain temperature even in varied conditions.

With the stock radiator, my gauge stayed at 3/8 on the flats no matter what too. Long uphills in the summer were another story.
Click to expand...

I disagree, to some extent. The NSX thermostat begins to opens at 76 to 80 C and is fully open at 90 C. There is hysteresis involved in the state change of the wax in the thermostat, but I won't go into that here. Once the thermostat opens and cooler coolant comes in from the radiator, temperatures drop somewhat, fluctuating up and down. When the outside air is very cold, there's more fluctuation than when its very hot. At some air temp, the thermostat will be fully open, the radiator working at its full heat exchange capacity, such as in Death Valley, and the temperature will begin to raise to unacceptable levels.

But to my original point, my 1984 Corvette has a digital temperature gauge, and you can see it hit the opening temp and see the temperature cycle about 5 C under cruising conditions. On my other cars, you can see the needle "wiggle" on the gauge under those conditions.

Note that there are not even temperature markings on the NSX gauge, and the check on the gauge in the shop manual is to "Check that the pointer ... starts moving toward the H mark" with a short to ground. Its better than an idiot light, but doesn't have the precision or accuracy found on some other cars or certain aftermarket gauges.

For 99% of the owners, this friendly :smile: esoteric discussion doesn't matter. But for those planning to run FI (or in abnormally hot climates), more HP = more heat generated => a bigger radiator needed to exchange the heat into the air. If I were adding FI, I would disconnect the wire from the temperature sender, connect an Ohmmeter to the sender, and measure the resistance to ground under various air temperatures and operating conditions before adding FI. Then, after the FI is installed, do the same tests to help determine what size radiator is needed or if a newly installed radiator can help the engine work in the same temperature range.
 
OLDMNSX said:
Something else that the Street Rod guys do is add stuff called "Water Wetter" to the coolant. They claim it helps with reducing the temps. A couple companys make this product. Red Line is one. https://www.youtube.com/watch?v=pApWgZdozQA
Brad
Click to expand...

I've also heard about this, but is it a complete replacement? If you broke down could you just add water and still be good (temp wise).
 
USAFguy22 said:
I've also heard about this, but is it a complete replacement? If you broke down could you just add water and still be good (temp wise).
Click to expand...

The Water Wetter is only a small 12oz bottle. It is ADDED to your normal mix of Anti-freeze / Coolant. If I broke down and had to add water I would do a flush and refill after I returned home and did the repair. Normal driving conditions with straight water isn't a problem. The Anti-freeze / Coolant just gives you the protection from freezing, raises the boiling point of the liquid mixture, and gives you corrosion protection.
Brad
 

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