I’ve bought some OAT coolant from Halfords, but I’ve read conflicting reports if I should use it or not? It already has red in the tank, just needs a top up.
You don’t mix coolant types. I used the red OAT for years in my Mk1 (owned since 2005), but then switched to waterless several years ago.
I was wondering about waterless earlier today. No specific issue, just building a list of things to do on my NC 3.75 and looked into that.
There is a lot of divided opinion. Any thoughts please?
FL22 as recommended by Mazda
I went for it, after a recommendation from Thrussington garage; they found benefits in track times.
On a 3.75 you could use A product called Ravenol HJC which is supplied concentrated from Ravenol’s own website at decent prices.
Would recommend you drain and fill the diff with fresh lube if you are keeping long term and it hasn’t been done recently.
Waterless coolant is completely unnecessary in a standard car and requires the previous fluid to be completely removed which is not easy outside of the realms of an engine removal event. Imho.
waterless coolant viscosity is ten times the viscosity of water-glycol based coolant. meaning its harder for the pump to push it through the radiator - likely to have less flow due to increased resistivity and that means the effectiveness of heat transfer change [ Q = q * A * (ΔT) ; where Q is hear and q is flow, A area of pipe and ΔT is the Texit - Tinlet ]
In addition your pump works harder, meaning that it will last less under normal operating conditions (and if you have an electric one in your car it will burn out)
Evans Waterless saved my motor when a fan failed. It never boiled, so no cavitation. New quality water pump in it at the same time. Mike Comber (MCR Racing, won loads of MX5 races) has been using it for multiple seasons in NAs and NCs, getting better testing times with it , and no impact on reliability. I’d go with his recommendations rather than anonymous on internet.
Its more viscous sure, and was hard to bleed the first time; a good hour to get it to burp.
Proper misbehaving when it overheated. 3 years on, the engine is running beautifully.
Nothing new, the Yanks have been using Redline Water Wetter in Miatas for decades; no one has wrecked their water pumps with it.
You will find plenty of data showing that with Evans, the cylinder head temperatures are reduced, and head gasket life extended (maybe not in that Elan article you read, which has been spammed on forums); boils much higher that water + antifreeze, So no pressurisation. Bonus is no water no corrosion. I can whip off the radiator cap on a hot engine without fear. Its expensive, but hw often do you actually change a quality antifreeze? And only expensive the first time, because the system needs to be flushed. After that, £60 a go. My conversion cost ~£100, but the costs were reduced, because the flushing agent can be used twice (used on another customer car).
That Elan article, which had the deltas etc equation, said there was speculation that pumps might no last as long. Speculation by Mr Bloke Down the Pub I guess. Open to examples of premature water pump failure actually happening.
Also, every responsible MX5 owner changes the water pump early, at probably less that halfway through its service life. You do a coolant change with a belt change, which of course means a pump change. And who cheaps out on a water pump?
I was irresponsible once, and didn’t change the pump. Pump started weeping at 80k miles… Lesson learned.
There was a post on this forum illustrating how a waterpump was wrecked bhy conventional coolant. The owner has pretty much no blades left, they had dissolved.
There is Evans NPG+, which is 65% less viscous.
Note, I did not convert to waterless because I thought it could prevent overheating (evidently it did not). Actually, I was attracted by the idea of increased reliability.
Hi mate, i didn’t really look at any external links, I just applied common sense.
I knew the stuff is more viscous and (as it usually happens with Americans) they go into much details about anything. However it does seem to have an influence of what pump you are using in your car. If its not man enough and cant cope with the liquid or simply won’t push enough liquid through to transfer the heat.
Heat transfer is proportional to the thermal conductivity of the liquid used but also the flow of the liquid. If comparing the two liquids and the flow is identical the more heat transfer would be for the liquid that can conduct more heat (higher thermal conductivity). Obviously if you are testing one liquid the more flow the more heat is conducted onto the liquid and transferred across to the radiator.
Because the two liquids have different viscosity and quite possibly different thermal conductivity you can’t tell which will work better in an existing system. This is because you have different thermal conductivity between the two liquids and as result of the difference in viscosity the flow will also be different. And if you have a thermostat you won’t see how your cooling system works - whether its better or worse because the thermostat will open at 80 decC.
I’m not saying its bad product, I’m just saying people need to understand what they are doing and how things will affect their existing hardware. Its basically logical to say in some cooling systems the pump will not be able to pump this coolant either because it cant generate enough flow or it doesn’t have enough power to cope with the increased viscosity of the fluid. On the other hand in some systems it will work just fine.
Reference
Davies Craig water pump
Can I use Evans waterless coolant with a Davies Craig electric water pump?
Panos:
This specific pump manufacturer, Davies Craig, has multiple versions that typically do not move enough coolant pending the type of application
Common sense tells you water pumps “will” not last as long. Or unsubstantiated hunch.
We are talking about one sort, well two sorts of cooling system; NA/NB and NC. Not trucks, TVRs, racing cars.
NA/NBs all have basically the same cooling system. Its not the case, nor an inference, that one NA will be affected, and not another because they have different water pumps. We have established in the NA/NB/NC, Evans works just fine (several years of track data for instance). In the context of a question on MX5 servicing, discussion of any other marque, real world or theoretical, is irrelevant.
Its not a single product, there are multiple products. I used Power Cool 180. Classic Cool 180 has different properties, NPG as well. There are 4 other varieties, all with different viscosities. The manufacturer also points out that when warmed, viscosities are similar to water based coolants. the most significant difference is at -40 Celcius. I don’t live in the Actic/Canada, so will ignore that. Might be different in a Nuclear Winter though.
I’m convinced it saved the motor. It was one of those sunny days, car hadn’t been used in a while, and I was driving through a town slowly, not really looking at the gauges much. Then the car started acting very oddly; poor idle, stutter, and the gauge was right over to the right, which might mean pretty hot or boiling (it rises quickly on a stock gauge). Limped into a MickyDs. I feared the worse, after a previous overheat when a heater hose disintegrated spraying water coolant everywhere. But the engine has been fine.
For me, it was a 23 year journey, ever since a technical presentation from Redline at one of the MX5OC Seminars I organised in Northern Ireland, back when I was competing.
Hardly any MX5 owners are using an electric pump, so red herring to obsfucate.
What people need to understand is what you think is going to happen, not what is actually going to happen in the real world.
What temperature your thermostat opens up depends on which thermostat you have fitted. There are a range available for the MX5. If you linearize your water gauge (resistor mod, to remove the dampener) or fit a “real” gauge, you can see what happens. Haven’t bothered with this car, but my 1.6 I linearized the gauge, and I could see when the thermostat was closed, when it was open, when cool mixed with hot water. Was interesting to watch (and necessary to understand how the bypass line blocks).
4 years on, I am very happy in my choice. Other than the time when the fan didn’t come on due to a corroded connector, the fan turns on and off normally.
One fear expressed about not switching is what happens in an emergency. You can add water, perfectly safely, It doesn’t congeal into some mess, it doesn’t grenade your engine. It just means you are no longer at 0% water. Evans rate their characteristics at 3% v/v water, so a top up is unlikely to lead to loss of “benefits”. And if you have to add a lot, then:
Of course, you have the argument of sticking to factory spec coolant that comes in a Mazda branded bottle. Perfectly valid argument, equally applicable to air filters, oil, oil filters, shocks, tyres, brake pads etc. Makes for dull forum discussions though.
We see the same discussion about E10. Could it damage the engine? Possibly, theoretically. Has it damaged a MX5 engine? After 30 years on service use, it doesn’t seem to do that.
