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Discussion Starter · #1 · (Edited)
I wanted to let you all know that you SHOULD NOT buy the Mishimoto aluminum radiator if you have a D16Z6 motor. Although their website states that the radiator is a "direct fit" for the D16 it isn't. The upper and lower radiator hose mounts are sized for a B motor not a D.

That means that the upper and lower hoses are 32mm (1.25") inside diameter instead of 28mm (1.125") inside diameter. You cannot stretch a hose to fit....I tried.
I called Mishimoto and they said that they know about this issue and that they are sorry. They did offer to refund the radiator purchase price once they received the radiator back. So, I am not out of the money...just time.

I wanted everybody to know that they should steer clear of this radiator if they have a D series motor. It appears that the fitment issue is due to the fact that the B series has 32mm upper and lower mounts on the engine side and the radiator side. The D series has 28mm mounts on the upper and lower engine side and radiator side. :bash

Other than that difference everything else fits. The radiator shroud fits. The fan fits. The coolant tank fits. The radiator cap fits. The radiator even fits between the engine block and the front frame mount although it is a squeeze as the Mishimoto is almost 3 times as thick as the stock radiator.

The only things that do not fit are the hoses.

This may seem to be a small issue...however, you can not purchase a radiator hose that has one end 32mm and the other 28mm. You can try to fit silicone hoses and stretch them out to fit 32mm. However, under pressure the silicone will split and fail. You can also try to fit a 32mm hose on both engine and radiator sides but the hose clamp will not hold when you reach the operating pressures of 14-18psi.

The Fluidyne, Mishimoto, Godspeed are all built for the B series and as such have the 32mm hose diameter. The Godspeed site says that they have a radiator specifically for the D but they say the measurement for the hose diameter is 32mm or 1.25" when it is actually 28mm or 1.125" So, even they are wrong. I checked with Honda and their stock radiator is 28mm or 1.125" Anything bigger and the stock hoses will not fit the thermostat housing or the upper radiator support housing.

The only other option I know of for an aluminum radiator is the Koyo replacement radiator :clappy. It IS a stock fit radiator. It has the correct upper and lower hose diameters. However, it is at least twice as expensive as the Mishimoto. So, if you want an all aluminum radiator with the correct hose size you can buy the Koyo for $400 :eek2 or the stock one for $65.

If anyone knows of another radiator that is all aluminum and has the correct hose diameters please post the manufacturer and purchase information. I still want a new radiator but cannot find one without this problem.

FYI
 

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Discussion Starter · #2 ·
Does anybody know if the thermostat housing for a B16 will fit a D16? Will the upper hose mount for a B16 fit a D16? If so then I could just purchase a set of B16 hoses and replacement mounts and use the Mishimoto. If not....well I am right back where I started.
 

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Discussion Starter · #4 ·
Yes, I consulted with the manufacturer before I purchased the radiator. They assured me that it would fit. It did fit...but the hoses were wrong. I knew the radiator would be physically bigger that was no surprise. What I did not know and what they did not tell me was that the outlet hoses were 32mm instead of 28mm. Koyo advertises these radiators as being different but Mishimoto does not. Mishimoto, Godspeed, and Fluidyne all say their radiators are a direct fit replacement but they don't say that their radiator hoses are 4mm larger in diameter. That is the important part. I have spent the day learning more about radiators than I ever wanted to know.

I want to turbo my D and asked the forum if the radiator would be a worthwhile upgrade since my existing radiator was cracked. Those who replied indicated that an all aluminum racing radiator would be good. However, I don't think anyone actually knew that the producers of aluminum radiators make them with 32mm hoses instead of the D series required 28mm hoses.

I checked around with other manufacturers and nobody but Koyo recognizes this difference. Koyo states that they make the D16Z6 radiator with 28mm inlet and outlet hose diameters.

What I wondered was whether anybody here on the forums was aware of this issue? It could save forum readers some time and frustration.
 

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Discussion Starter · #6 ·
This sort of thing is kind of retarded, you know. Why would Honda make one engine with 32mm hoses and another with 28mm hoses? Wouldn't have it made sense to use the same hose sizes for all years? I mean the flow rate for 32mm hoses would be slightly higher and that would only help the D16 motor. Plus, the uniformity of parts would be more typical of Honda's concept of less-is-more.

Anyway, my intent here is to try and find an aluminum radiator with 28mm upper and lower radiator hoses. So, do you happen to know of one that is made that way other than the Koyo? I would really rather not spend $400 on a radiator.

I double checked with Godspeed and they measured their D16Z6 radiator and found that even their measurements are wrong. Supposedly, they are going to change their website to address this finding. I wouldn't expect that to happen though.

For the betterment of the SuperHonda forum members: Please, double check your hose inlet and outlet sizes before you buy....
 

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Discussion Starter · #8 ·
CX Racing does have a radiator for the D16Z6 Del Sol Si. They state on their website that their radiator hose size is 1.1 inch which makes it 27.93mm that should do. Hopefully I can get one for cheap and without a lot to ship.

Thanks for the suggestion.
 
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