R3 Radiator broke, looking for cooling system replacement help :)

[Krystian Pogubilo]

Hi,

After owning my R3 for around 4 months now, I've found it's a fantastic car but rather difficult to get the correct information about replacement parts.

I daily drive my R3 and now the radiator is burst...

In my search for good after market options. I have found a lot of conflicting information with what fits and doesn't fit the R3. To my knowledge is has a slightly different design to the S1, thus making my options limited.

Ideally I would want a good aftermarket option as I am thinking of possibly turbo charging the car later down the line and I do drive it quite hard quite often. What sort of radiators are good options? I have seen a lot of people saying the koyorad is a great option (although seems quite expensive depending on the seller) but there's some conflicting info on this too!

Essex Rotary has the KoyoRad 48mm for the R3 listed, but heard Essex Rotary has been having some customer support problems recently

Racing Beat has a R3 KoyoRad listed for £500+ with 36.5mm, to my awareness, Koyorad website only lists the 48mm as compatible. Seems more expensive than the others too?

RRP has 53mm that they mention can make in house adaptations for but haven't replied to my message yet (has only been a day, but it is showing as read )

Some need adapting coolant hoses, some don't, not sure which do. I want to also get replacement silicone hoses all round but again, the design for the R3 seems to have changed from S1, all the kits list support from 2004-08, haven't found 2008+ ones yet. Same story with uprated cooling fans which I am considering doing while I'm there. If anyone knows anything about this, I would be grateful!

I can make some adaptations through fabrication with my brother if necessary to mounting etc. But I don't want to chop the car up. All of the information so far isn't clear from what I have found.

Any help would be fantastic. I don't mind waiting a little bit for parts, but not months since it's my daily driver. Same goes for cost, as long as I know I'm getting something good, I don't mind spending a bit more.

[warpc0il]

Focusing in the last question first, most "uprated" cooling fans are actually a downgrade compared to oem.

The oem arrangement has two 2-speed fans, and a complex control matrix to determine what combination to use under what conditions. The fans even have a different number of blades, to avoid beat vibration.
There isn't a significant shroud around these fans, so movement of the car through the air is sufficient 90% of the time, as long as the undertray and foam rubber surrounding the core are in place, so air can't leak past.

Most aftermarket options are based on "universal" fans kits, adapted to fit, often with shrouds, so little free air can flow through the core.
The one use case that might benefit from this arrangement is a dedicated drift car, that spends 99% of its time not pointing in the direction of travel, and needs the cooling air sucking through.

For the radiator, I'm happy to recommend Essex Rotary, even if Aston is often too busy fixing people's cars to answer the phone, at times. They usually response to FB messages.

You need to check why the radiator has "burst" as that's not a common failure on these cars. The AC condenser mounted in front of the radiator provides protection from stones etc. The only common cause of failure is the small plastic pipe to the header tank being damaged, usually when replacing the tank to fix a duff level sensor.

If it has truly "burst" then that would indicate excess pressure, which could be a result of an aftermarket cap being fitted. Some are convinced that increasing the pressure rating of the cap is a good thing, which it isn't, and we're aware that the quality control on some of these products is so bad that the actual relief pressure may be considerably more than marked.

It's also possible that a coolant jacket seal has failed, so compression gases are pressurising the cooling system, so I'd be using one of these kits to check the coolant https://www.ebay.co.uk/itm/127278886039, before replacing the radiator.

[Krystian Pogubilo]

Thanks Warp!

I will keep the original fan and shroud in this case. I do occasionally drift but certainly not often so I'll keep it stock in this case. Although it would be nice to have it shiny haha

I have read about the rubber surrounds and under trays being important so I will make sure those are in place.

As to why it burst. I may have used the wrong terminology. Essentially it has a hole/dent on the face facing towards the engine bay. After replacing the old coils, lead and plugs. I took it out for a nice 30min back road torture test. When I returned, I had a coolant level light on, wonky battery and a bit of a puddle under the car. The battery tray came loose on one. I am missing a screw/nut from it and I have a hole near where the fan blade meets the rad (the fan doesn't touch, but it would with a screw in-between it). That's the conclusion I have came to as the rest of the rad facing the engine bay is in good condition.

I will most likely give the Essex rotary rad a go since this is the correct one stated by Koyo that will fit into the R3. Price is decent too relatively speaking. Do you know if I'll need any adapter hoses? I have seen a lot of places are selling adapter hoses for the Koyo radiators but not sure if it's needed for this one / would I need a different adapter kit since mine is the R3? All of the silicone replacement pipe kits don't state support for the R3 or 2008+ models which is strange to me. I would be happy replacing 15 year old rubber pipes while I'm there, but I really don't know what I need here.

[New Duke]

Stick with the Koyorad in 48mm, new Mazda original radiator, or the RRP one (assuming you can get them to make it fit or adapt it yourself).
The foam around the radiator won't fit any that is thicker (or bigger in general) than the stock one. So you need to fit your own foam afterwards if you're going thicker, otherwise it will run hotter. Maybe good in winter, not good on track. So that is up to you.
So unless you pack around it properly a thicker aftermarket radiator actually cools worse than stock.
The part number you want for the Koyorad 48mm is HH062267.
That's the one I have and it fits just fine with no need to mess with different hoses.
Keep the stock fans. On the 48mm Koyorad and stock Mazda one the stock fans just bolt straight on. You'll need to check about other rads.
As Warpc0il said your radiator shouldn't just burst. So there may be another problem to solve. Unless it got damaged or just corroded and leaked out, for example.

Edit: Just seen your reply and just looks like it got damaged.
No need to replace any of the hoses unless they're damaged or you really want to. The stock ones generally age well.

[Krystian Pogubilo]

Thanks New Duke,

That sounds good, I'll get the Koyo 48mm one in this case. Just to clarify, do I need to change the packing for this one? I believe it is bigger than the standard one but I haven't got the dimensions for the R3 stock radiator. I believe the S1 is 36mm, not sure about S2 / R3.

I am also a bit new to these in general, would there be anything that would be good to replace while I've got the front end disassembled?

[New Duke]

The stock packing won't fit the Koyo 48mm I'm afraid. It may only fit the Mazda stock radiator.
But everything else about that radiator (I believe, it's been a few years) just fits as is.
You don't 'have' do fit new foam around the radiator, I never did as I was lazy, and you may never notice not having it. It just 'should' be there. Mine ran hot on track on hot sunny days and that was why. Which is an extreme use case most cars never see. But otherwise it wasn't noticeable. I had to mention it though.
While you're taking the front end off just be very careful of the fog lamp wiring as it is delicate. Also the washer fluid pipe, clamp that off to save losing all your fluid.
Personally I have a 'if it ain't broke don't touch it' mentality. But while you have the front off check out the condition of the oil coolers for leaks. Maybe also consider removing the VFAD (there's a guide in the DIY) and/or fitting a Revi ram scoop if you haven't. But those are mods that change the characteristics of the engine. So have a read on here and see what you think about them.

[Clive]

We have sold Koyo radiators for 24 years with no issues and I even use one in the Race Car.
The Koyo R3 Rad we sell is a direct replacement with no messing about.

You will find the Series 1 and R3 radiators are different, the fan shrouds are different and I have known people fit one to the other and have issues.

As above, stay with the stock fans as these are very good.

https://www.racingbeateurope.com/mazda- ... 1276-p.asp

I hope this help.

[Clive]

BTW, no way do you need a 53mm rad.

Years ago I sold someone who was desperate for a radiator on his track car, but I only had an RX-8 one on the shelf.

He fitted that to his RX-7 FD and years on its still on the car, so as said you don't need to adapt a fat rad in

[Krystian Pogubilo]

The stock packing won't fit the Koyo 48mm I'm afraid. It may only fit the Mazda stock radiator.
But everything else about that radiator (I believe, it's been a few years) just fits as is.
You don't 'have' do fit new foam around the radiator, I never did as I was lazy, and you may never notice not having it. It just 'should' be there. Mine ran hot on track on hot sunny days and that was why. Which is an extreme use case most cars never see. But otherwise it wasn't noticeable. I had to mention it though.
While you're taking the front end off just be very careful of the fog lamp wiring as it is delicate. Also the washer fluid pipe, clamp that off to save losing all your fluid.
Personally I have a 'if it ain't broke don't touch it' mentality. But while you have the front off check out the condition of the oil coolers for leaks. Maybe also consider removing the VFAD (there's a guide in the DIY) and/or fitting a Revi ram scoop if you haven't. But those are mods that change the characteristics of the engine. So have a read on here and see what you think about them.

Thanks for the help with this. I'll probably re-do the foam in this case then as I do drive it hard + I do want to do track days/nurburgring etc. Maybe even a turbo in the future if Josh from Blackstar gets it ironed out.

I believe I have already removed the VFAD for the AEM intake kit I installed. Revi ram scoop is also irrelevant in my case but thank you for the heads up!

We have sold Koyo radiators for 24 years with no issues and I even use one in the Race Car.
The Koyo R3 Rad we sell is a direct replacement with no messing about.

You will find the Series 1 and R3 radiators are different, the fan shrouds are different and I have known people fit one to the other and have issues.

As above, stay with the stock fans as these are very good.

https://www.racingbeateurope.com/mazda- ... 1276-p.asp

I hope this help.

Hi Clive,

Thanks for helping out. What model is the Koyo rad you sell for the R3?

[Clive]

If you are interested PM me and I will check availability on Monday for you.

[350matt]

any foam rubber that can take the temp will do the trick, this stuff I believe is used by a number of folks

https://buyinsulation.co.uk/products/ka ... gImofD_BwE