Hi all, I’m about to do a full fluid change service on my 95 Eunos 1.8.
Oils and brake fluid sorted so I’m after advice on antifreeze.
ive searched this and other forums but there doesn’t seem to be a definitve answer I can find.
So, what would seem a simple question. Should I fill with blue or pink antifreeze?
A simple explanation of the differences maybe, but please don’t cloud the issue, that’s what seems to happen when I read other posts on the subject.
Many thanks.
D
It’s more about how strong of a mix you do, so it goes down to a lower temp before freezing not about colour?
I am not sure colour is not a guide of how good it is and may be just a dye.
Pink antifreeze tends to be the HOAT antifreeze. Blue is a Phosphate enhanced OAT antifreeze. There is some controversy as to whether a blue antifreeze is suitable for Japanese waterpumps.
I switched to Evans waterless coolant (expensive, because you need to flush clear of water first) on the basis of no pressurisation (so should be better for an older engine, with respect to hoses and gaskets), which was the main benefit, and supposed improvement in power on the track (some evidence, likely marginal, but I can understand the theory behind that).
Its also about how much protection you want for the galleries, cavitation etc. Antifreeze is also a good idea in hot countries.
I very recently had a conversation at my local motor factors about this subject when considering which coolant to use after fitting a new cambelt.
The important thing is not to mix red and green and so if changing coolant types, a very thorough flushout is needed with clean water (I use de-ionised or distilled water when topping up). The old fashioned, Blue coloured glycol based coolant is best avoided - it doesn’t give the same protection as the later green or red types.
The motor factor chaps recommended red, which would have been cheaper to buy and does have a longer life between recommended changes, but seeing that my car already had green coolant and having flushed the system I saw it was like brand new inside, although the car is 21 years old, I decided to stick with green.
I have considered “waterless coolant” in the past and acknowledge that it is a very good product, albeit rather expensive. However, it always worries me that it’s not widely stocked and if the cooling system ever needed working on for whatever reason when away from home it might be a major problem to get a replacement supply to refill with.
The definitive answer is if the Mazda dealers parts department still sell Mazda Super Coolant, that is what Mazda recommended for the pre mid 2005 cars.
The argument about which is best goes round in circles.
Use what Mazda recommends if it is still available.
I do not know if Mazda still suply it but there are stocks in Germany.
In over 20 years of MX5 ownership, and well over 300k kms in the said cars, I have had a few failures, all attributable to failure due to pressurisation. I am expecting such failureds to be a thing of the past. Other failures might happen. Adding water to Evans isn’t going to cause any harm; the general recommendation is to change the coolant at the earliest opportunity, a £50 cost. Its basically pure glycol. Its in there for the life of the engine, as long as its not contaminated.
As per engine oils, cleaning products and tyres etc, the subject of the most appropriate coolant is often subjective and controversial. 
I researched the use of Evans and similar “waterless” coolants quite a long time ago in some detail and as I said, they are a good product. It’s just my personal choice not to use it in my MX-5. As I wrote, the cooling system of my car’s been totally fine on the green stuff for over 21 years now (its cooling passages are so clean they look like those of an almost brand new car) so in my view there is no real need to change over to it.
The green coolant I bought very recently cost me £12 for 5 litres. Evans would cost almost five times that (obviously including the prep fluid, which is more expensive than the basic coolant itself). I can get de-ionised water for £3.50 for 5 litres, distilled for free.
I did fit a new radiator when I did the cambelt change about three weeks ago but that was because of external, not internal corrosion and ageing plastic tanks which I decided were probably past their safe life. The car will probably bodily rust away before the cooling system rots out.
Fair enough, but fears about not having Evans in an emergency should be dispelled.
OP’s question has been answered.
Expanding on post #4 from PaulW - if you do mix glycol antifreeze with OAT antifreeze they will react and form a gel (not good).
Don’t overdo the strength. You do get protection to a lower temperature with a stronger concentration, but the protection temperature bottoms out at about 50% and actually starts to rise again after that.
Thanks for the replies everyone.
I’ve just spoken to my local Mazda parts supplier ( Littlewick Green Garage ) and they said Mazda recommend Mazda badged green antifreeze at £53.18 plus VAT for 5 litres. I’m guessing this is FL22. MX5Parts advertise this for £15.82 for 5 litres, but are out of stock. They also say it is for MK3 and MK4 cars only, so I’m still confused. Given that 5 litres of Halfords ready mix OAT antifreeze ( which it’s web site says is for my car ) costs £20.50 it seems a bit of a no brainer if FL22 is compatible with MK1s. Any more thoughts?
D ( still confused (-:
Hi, Like you I spent some time looking at this subject for my 1992 Mk1. I recently changed mine, it had a blue antifreeze of unknown origin in it, but after reading various posts on here regarding the Japanese engines and silicants etc, I went for the Halfords Pink OAT ready mixed. As previously mentioned give the system a very good flush before refilling with the OAT coolant. Seems okay at the moment!
Good point about the mixture strength of the coolant. Water has a far better specific heat capacity than “anti-freeze” (approximately twice as good a coolant as ethylene glycol) so it’s best not to over do the concentration in an engine that needs the very best heat transfer. I don’t think that’s a major problem with the early MX-5s though.
Combemartin,
As per my original reply, people do tend to be very loyal and stick to using what they already prefer (regarding coolant, oil, tyres, cleaning products, favourite football team etc). I’m not surprised that you are still confused, having seen all the contradictory advice here, as expected. I’d say make your own preference (certainly use the previously mentioned waterless type if you wish), but avoid the blue ethylene glycol type and then just make sure you adhere to the recommended lifetime of whatever coolant you do use - this does differ and it is important.
I must add that in the forty five years or so of maintaining cars and rebuilding various engines (my own small fleet of five we have here plus those of family and certain close friends who trust me to do a proper job), I’ve never had ONE fault caused by a “wrong” coolant, even though most of my vehicles in the past were just filled with the proper concentration of the old fashioned blue stuff due to the use of brass in the radiator, which can be adversely affected by more modern coolants. My supercharged competition car still uses the blue type without any issues whatsoever. I might change it to a more modern type, but I’ve not been in a hurry to do it because as a project car it gets modified on a fairly regular basis so the coolant gets changed a lot more often than that of many cars (first built that one from a bare chassis almost 20 years ago). The cylinder head of that one is about to be changed for a modified one very soon (I’m redesigning the fuel injection system at the moment and lowering the compression ratio plus a couple of other mods so it might be a good opportunity to use green, red, or even waterless… but never a mixture of any two!
Just found this Mazda Technical Bulletin which seems to say that FL22 is suitable for older cars.
Service Bulletin
© 2007 Mazda Motor of America, Inc.
Mazda North American Operations Irvine, CA 92618-2922
Subject:
PRE-MIXED LONG-LIFE “FL22” ENGINE COOLANT
Bulletin No: 01-033/07
Last Issued: 12/14/2007
MULTI-MODEL - PRE-MIXED LONG-LIFE “FL22” ENGINE COOLANT
BULLETIN NOTE
This bulletin supersedes the previous bulletins issued on 08/01/07 and 01-029/05 issued on 11/04/05.
Bulletin No: 01-033/07 Last Issued: 12/14/2007 © 2007 Mazda Motor of America, Inc.
When coolant replacement becomes necessary for older Mazda models not originally filled with FL22 coolant, FL22 coolant can be used. If FL22 coolant is used for older models, be sure to place a FL22 sticker on the reserve tank or degas bottle to indicate FL22 coolant is being used. Six (6) FL22 stickers are included with each case of coolant. Additional FL22 stickers can be order through MStore (p/n 9999-95-FL22).
NOTE:
• In the case of older models, the coolant replacement interval is every five (5) years or 60,000 miles (96,000 km).
• FL22 coolant is compatible with current (Green) ethylene glycol coolant.
• If FL22 coolant is mixed with existing Orange coolant, coolant color will turn black. For customer
satisfaction, DO NOT mix FL22 coolant and Orange coolant.
PLACE FL22 STICKER ON RESERVE TANK OR DEGAS BOTTLE
Just a quick update, though not much of one. I contacted my local garage again to clarify what coolant they were recommending. I asked if it was FL22 or Mazda Super Coolant or something else. The answer was " not really sure, it’s just got Mazda Coolant written on it " I then asked if it was concentrate or pre mix and was told it was pre mix so it would cost me £127.63 to change which seems mad. I then phoned another dealer and asked the same question. They said they only stock FL22 which was not suitable for my car and if I brought it into them to service they would just use " standard antifreeze " whatever that is.
So I’m not that much wiser. Currently I’m thinking Halfords pink OAT antifreeze or, if the above service bulletin is correct, FL22.
When taking into consideration the shipping costs from MX5 Parts and the 10% discount the club gets from Halfords there’s not much price difference but FL22 is out of stock.
Oh decisions decisions. Any other thoughts from the wise?
Thanks again.
D
Slightly contradictory to raise the issue of specific heat capacity and water content while also acknowledging that Evans waterless coolant is ok.
For precisely that reason I do not understand how waterless coolant can be “BETTER”
Regarding the OP. In a 1995 car you may as well use the pink OAT or whatever at 50/50 concentration. It’s much more about the existing condition of the cooling system and flushing out any scale and debris than any individual differences in coolant types.
Mk375, Yes it is contradictory. As with most things in engineering, solving one problem often brings up a possible issue elsewhere. As I said, I don’t think that early MX5s suffer from cooling capacity issues so in this case it shouldn’t cause a problem.
I have used pink stuff from GSF or Euro Car Parts for the last 20 years in all my cars.
50/50 mix with the water from my garage dehumidifer.
No problems whatsoever.
After months of pondering I’ve finally got round to buying some antifreeze. After a bit of phoning around I got 5 litres of concentrated Mazda Super Coolant from a Mazda dealer for £16.
D
Well I finally got round to doing a coolant change.
Flushed the system four times including running the engine each time to make sure the thermostat was open and the water was circulating. New coolant added and the system burped. All went well.
Only thing is the car seems to reach normal operating temperature quicker. Needle just below the middle position. I can’t put a definitive time on this but I’m sure it is quicker. Heater works well and the coolant level remains constant.
I’ve driven over 200 miles since the change and temp remains just below the middle.
I’m sure ( hope ) all is well but thought I’d ask.
Any thoughts?
Thanks
D