Your logic is flawed, the running temperature of an engine in Alaska and Hawaii is the same, so the viscosity when up to running temperature would be the same both places. The cold temperature is correct though. A cold climate is more likely to have a need for a runny oil at cold temperature.
For temperatures I see in the south of England, an 0w30 and a 5w30 are for all intents and purposes the same as it doesn’t get cold enough to make a difference. The viscosity at -25c is irrelevant if the coldest it gets is -10.
Some will say, only buy an 0w oil as you can be sure it is synthetic. You can’t make an 0w weight mineral oil, not sure this is true.
Many oils labled as synthetic do not legally have to be 100% synthetic. Look closely at the label and you will see stuff like ‘Synthetic Technology’. I have even been told oils labeled as Fully Synthetic are not always 100% synthetic. I look for marketing or tech documentation that states that the Base oil is synthetic. Whether it matters is a whole different question.
The running temps should be the same, however the ability of the cooling systems to maintain that 86 degrees in temps above 30 varies considerably depending on load and airflow. A mountain pass in the heat will result in higher oil temperatures. Whether that will require the use of a higher grade oil is anyone’s guess but a 5w30 will be thicker than the 5w20 in this situation.
Regardless my point is that the US cars are specced with an oil that has a smaller temperature range than that of the UK cars so the environment in which it is being driven was likely not a deciding factor when Mazda specified the oil grade. Thinner oils do give better mpg and power figures which may be one of the reasons (others include testing methodology and internal changes to the engine itself) that Mazda list the bhp figures higher in the US too
Not in my experience. I spent forty years working in technical positions for a very large vehicle manufacturer, our company had a huge technical centre including many engine test beds. We had an extensive laboratory at our plant and worked with oil suppliers to ensure we used the best for our vehicles.
Okay, so based on those 40 years experience which are the best?
If some of them aren’t as good, (but still meet the specifications) why aren’t they as good?
What do you use that is “the best”?
With no disrespect that is quite a bold statement to make and perhaps we would ALL be interested in why.
Many thanks.
Mobil Super 3000 FE 5/30. Comes in 5 litre cans, switched to this when castrol reduced the can size to 4 litres.
Have used this for most of the car’s 108,000 miles. Does get changed at less than the recommended mileage, currently annually, 6k miles/year (used to be a tad more!)
PS I usually buy a can when it’s in Halfords sale, whehter I need it yet or not, so save a few bob there (add in Barclaycard/Goldfish tokens and it gets even cheaper!)
I can’t say what is the BEST for an MX5, the oil our company used was Mobil who formulated a specific oil which was sold under our brand name and not sold to any one else.
But if you use oil from one of the major oil companies, Shell, Mobil, Castrol, etc then you cant go far wrong. These people invest tens of millions a year in R&D every year. Something smaller concerns can’t match. I use Mobil One in my MX5.
The biggest advantage these people have is their expertise in additives and how they produce their oils.
Don’t be so sure that major companies can’t get it wrong. About 10 years ago a global manufacturer missed a key ingredient out of the grease used in train traction motors. We didn’t find out until after about 6 months train traction motor bearings started failing. A majority of uk electric trains had to be stopped for a rolling programme of bearing replacements. The manufacturer did admit liability and bore the costs
Thought this might rumble on…
I use Total Quartz Ineo MC3 as recommended by Total.
Another reason is that a few of the main manufacturers have changed from 5 litre containers to 4 litre containers, annoyingly so!
Whats that all about, (Money I know) we all know “a lot” of engines take 4 litres +
The way I see it, it’s still a user preference thing.
Also it’s annoying Mazda Main Dealers charge £10+ per litre.
mk375 pack of cards maybe
Apologies to all for reviving this. I have a 2006 NC 2.0 auto on its way from the far east. I have used Fuchs fully synthetic oils in all my cars for years now.
Am I right in thinking I need (any) 5w-30 fully synthetic oil please, or is it more complicated than that?
In short, yes, it’s more complicated than that, but not by much.
You should only use oil that meets or exceeds the manufacturer specifications… And the general consensus among forum members (myself included) is that Mobil 1 Super 3000 is the best.
You can use Fuchs if you wish, there’s absolutely no issue, as long as it meets the exact requirements.
Just thought I would update on the Kerax Hyperdrive oil I have been using (read the post up the thread a bit).
I subsequently found out that Kerax were challenged on the accreditation written on the spec of the oil. They revised formulations, were retested, and were fine. Except… a few months later they were retested and failed. As a result they were reported to trading standards: https://pmmonline.co.uk/news/vls-escalates-engine-oil-case-to-trading-standards/
Whether the specific (and possibly very narrow) tech spec failure has any bearing on 99.9% of users is a valid question, but personally I think if they can’t be trusted on quality control enough to meet the spec they put on the bottle, then I will avoid in future.
I am running the oil in the MX5, and it will be swapped out in the next couple of weeks - it has been in there for about 6k.
I also ran it in our CX5 diesel. It may be coincidence, but we had it jump into limp mode on occasion, and the dealer diagnosed an exhaust pressure sensor issue and swapped that out. The problem remained, car would go into limp mode (sometimes once a week, sometimes twice a day), which would be fixed by a switch off and restart. Several other owners report the same thing on various forums. However, since the last service when the Kerax was dumped and replaced with whatever oil Mazda fit, the issue has never reoccurred. Might be coincidence, might be they jiggled the correct wires at the service, but it might also be that DPF that is known to be very sensitive to non C3 oils did not like the Kerax.
So the next low cost oil that is going in to my MX5 is likely to be Fuchs Titan XTR which is on the Opie list of suitable oils and costs around £20 for 5L on Amazon. No rush, so if a better deal comes along in the meantime… keep hoping Halfords will repeat their 50% off offer on Castrol sometime.
There’s some good deals on the web, very low prices and free delivery. I usually buy my oil and provide it to the dealer to use. Saves me a considerable amount.
Yes, definitely pays to shop around. Just be aware of the number of counterfeit products that are available; so if buying online be certain of the reputation of the seller. I had a quick look this morning and there were some good prices on oil from a chap with a made up name and feedback from only about 100 people. I would avoid him, perhaps unfairly, but I wouldn’t risk it to save a fiver. I expect he will disappear and change user name in a few weeks implying either he was not keen on being traced for some reason…
Also be aware of old stock - I note the Mobil tubs have a shelf life warning on them, although most do not.
