I use Nulon 10W40 (apparently full SYN but doubt it) and change every 3000km.

As a general rule, full synthetics will perform better than blends which will perform better than non-synthetics. Nulon Synthetic, Valvoline Durablend, Royal Purple, Amsoil did well in tests I have seen. Castrol, Mobil One - not so much. Royal Purple and Amsoil are formulated with extra additives to cope with extended drain intervals - so the cost per km doesn't have to be any higher than cheaper oils. I use Royal Purple and it does a good job for me.

As engines wear and the clearances get bigger, a thicker than standard oil can help. At 120,000 kms you probably don't have enough wear to warrant it.

A good oil filter replaced regularly is just as important as the oil. Look for the "absolute" micron rating (means 99% efficiency), not "nominal" rating (traps only 50% at that particle size). Wear increases exponentially with particle size. A typical filter is 40-50 microns - some are even worse. A 30-micron filter can reduce wear by about 50% (vs 40 microns), and a 20-micron by about 2/3. Among the best of the commonly available filters is Ryco at about 30 microns. Ford Racing Performance, Amsoil, Donaldson High-Efficiency and Royal Purple and others are better again (25 microns down to about 17). But the the smaller the particle trapped, the faster the filter fills, so the more often you have to replace it. A full filter opens the bypass valve and filters nothing at all. There is minimal benefit below 25 microns. I use Ford Performance Racing filters.

But, whether filter or oil, brand names alone are unreliable - some little known brands are excellent, and some well-promoted brands are worse than average. And more expensive is not necessarily better.

There are some other threads on FM that have links to tests, but I'm too lazy to try find them at the mo.

I use genuine Mitsubishi Engine oil of the 15W50 viscosity. It keeps engines very clean, and is abled to be used in some light diesels too.
I change it at 5,000km or 6 months, as I do reasonably short runs.
Read the small print at the photos.

 

 

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Please tell me you are not talking about those stupid wear scar tests.

I've run castrol gtx previously and I wasn't that impressed, I swapped to the repco branded penrite and it's a bit better.

I'll be trying out royal purple in my new engine and see if it really lives up to its name, being 100 dollars a bottle...

Castrol Magnatec for me. 10W-30

Shell HX5 15W/40 for me. I also use it in the Mrs' 323. I was surprised the SOHC 1.8 specified the same oil.

Whats everyone's take on Castrol Magnatec? Since trying it, I'm really not convinced it's as good as Castrol make it out to be.

Yep. It's a common way of measuring an oil's ability to reduce friction and prevent metal-on-metal contact. And it's relevant to what happens in an engine. Happy to learn why I should ignore the results though.

Magnatec - My opinion: Last time I used it I broke an oil ring... probably un-related but I was still not impressed with it. haven't used it since. It did instantly make engine noise louder which in my book is bad.

Everything I've heard about it: Bad.

Because the test is very easy to manipulate.
Because nowhere in you engine are there two surfaces that contact each other the way that test does.

It's a common way of measuring an oil's ability to reduce friction and prevent metal-on-metal contact.
The test actually shows what happens AFTER there is metal to metal contact.

It only tests fresh oil. Your engines oil IS contaminated the second you put new stuff in and start the engine.

It doesn't show the oil ability to deal with heat, with acid, with petrol dilution.

This will change your mind, test some 75w90 gear oil on that stupid machine. When it kicks the a*** of all the engine oils will you start using gear oil in your engine?

True. There are a lot of other variables inside an operating engine. But these would apply equally to all oils. I have also seen long-term tests of premium synthetics, and the relevant oil characteristics don't change radically in use - even over 20,000 kms. The top-up oil at filter changes is enough to keep a good oil within spec in an engine in good condition.

The testing I have seen was comparing oils of similar viscosity. Given a choice between one that prevents contact damage and one that doesn't, I would rather have the protection - even if I never need it.

Independent tests I have seen show that premium synthetics definitely reduce friction and produce a measurable (though slight) increase in power. Less friction has got to be good.

But all that's just based on the testing I was able to dig up - FWIW. If there are sources of more relevant comparison tests, I would really appreciate your pointing me in the right direction. Can never be too informed. Thanks for your help.

I use Penrite HPR30 20w60 in my eb 3.9, loves it, engines cleaner then old mates fagna engine above and it stayes golden on on the dipstick for 3000k, change it before 5000ks.
I use it because of a slight bottom end knock on cold start, no knock with this oil and holds good pressure too.

The only test that is relevant to the individual is used oil analysis.
That tells you how your oil is working in your engine, not how the oil performs in a lab test.



That oil does not exist. IF your engine ever gets the point that it needs to rely only the extreme pressure additives your engine has seconds to live, it will either get oil flow back or it will fail.

I've seen results of test between many oils and the difference between the best of the best and te worst of the worst was so small that it really meant nothing in terms of 'added protection' in a boundary lubrication situation.

You are far better off choosing an oil based on its ability to stay in grade with out needing VIIs, its ability to deal with acid build up, its ability to deal with petrol dilution and its ability to keep the inside of your engine clean.


I'm not going to link you to any test result as I fear it will only confuse you more then you already are and re-enforce your misconceptions.

We use it a tonne at work for cars under 100,000km or cars that specify it. That being said, I put it in my car, and it likes it a lot more than the thicker oil (Castrol GTX 15W/40)

As long as you're not boosting over 15PSI or running the 1/4 mile every week, it'll be fine.