Oils Aint Oils <Merged Thread>

[bjc]

I have just always used royal purple 10/40. When I tried a 0w50 in my AU the head used to tap/knock all the time until hot, it was just to thin for the engine on start up. Obviously tolerances must be alot tighter these days to recommend the zero weight.

No tapping or knocking with 10w either btw.

[Vevapower]

I use Brad Penn 10w 40 but I have no cat so best oil for me!

Go the Green!

[Garrettba03]

I just wanted to add I have a baxr6t with high 190kms and was running 10w40penrite everyday synthetic and I can tell u it ran really rough for about 2-3 minutes from cold till it got warmer and sometimes not very happy at running temps (but nothing like how crap it was at cold temps). Does not like 10w at all this is now in winter. Got worse the long ier the oil was in there. Changed 4000kms after with penrite sin 15w50 and...all problems gone. Really think with more power should use a thicker than factory spec oil real synthetic. How much of my problem was due to bigger clearences of high km's, thin oil, oil breakdown from high turbo temps I'm not sure but car hated the 10w40

Maybe it wasn't due to the 10w but the overall thinness of the 40 weight...either way car ran bad

Not sure if its from the 10w or the 40 but car did not like somethin that's for sure

Edited 30/07/11 09:48 AM by tab

[aiboart]

That really sh*ts me because I sent an email to Nulon a while ago asking them for there advice with the extra power that I was running and they recommended the 15w50 which I have been running for the last 25k (just serviced it @55k with 15w50 again,do it every 5k).

I'm really over this subject how can Ford and other oils say run a 15w40 and others say a 0w40 for the same motor???

My way of thinking was with the extra power going up to the 50 wouldnt be such a stretch with the extra boost etc...

I just think that I will give the 0w40 a go on the next change to see what it is like....very confused I'm going outside to have a beer and talk to my dog about it....haha

1-

The oil recommendation include an assumption as to how you might drive the car.

Two cars can have the exactly the same engine, however the oil manufacturer may recommend a thicker oil for the sportier variant of the car.

Why?

Because they think that the sportier car might be driven hotter. By driving harder and longer or even on a track, the car's engine will be hotter and hence a thicker oil is needed to maintain oil pressure. That's it.

Of course if the sportier version has an oil cooler you might be back to square one and the original oil recommendation applies.

One might expect that a modified car will be driven in a more spirited manner than a standard car.

In short to answer your question, it's a informed guess.

2-

With respect to 10W-40 and 15W-40, the trick is to remember that the numbers Do Not relate to the absolute viscosity of the oil.

At start up when the oil can be expected to be in the 10W range it is exceedingly thick. It is tens of times thicker at that moment than when operating at the '40' weight temperature range.

So what gives? How can the 10 weight be thicker than the 40 weight?

The answer, just to repeat the above, that the 10W-40 designation does not indicate absolute viscosity.

Instead what those numbers are telling you is that when cool the oil operates like a 10 weight and when hot it operates like a 40 weight.

What they don't tell you is than a cool engine oil of low weight is always much, much, much thicker than a hot engine oil of high weight.

3-

15W-40 is cheap mineral oil and Ford knows that some of its fleet buyers do not like spending money on cars.

High range mineral oils like 10W-40 are really 10 weight oils with lots of temperature sensitive thickening agents. As the oil gets hotter, the thickening agents cut in and do their job and limit the extent of viscosity loss to that of a 40 weight oil at the same temperature.

The problem is that if cheap thickening agents are used these can degrade prematurely and or in high shear conditions, so that the oil now now longer operates as 40 weight when hot. Instead the oil now stays as 10 weight when cold, or hot. This is very bad.

A 15W-40 oil helps avoid this problem in two ways. One, it has less thickening agents. Two, the base oil is already a 15 weight. The downside is that 15W has a higher viscosity at startup, hence delaying the onset of dynamic lubrication.

4-

A 0-40 oil is a synthetic oil. It has a different base chemistry to mineral oil and the above points simply do not apply. A synthetic does not shear back thickening agents. There arn't any.

Again a point to note is that when operating at the 0W temperature, the oil is much thicker than at the 40 weight operating temperature, so there is no issue with 'low' viscosity there.

However, synthetic oils do not have the residual stick ability of a mineral oil. This could be the potential source of clatter reported by some 0 weight synthetic users. Then again it may not.

[Kroozin]

that's some good info there aiboart..

Ive had a few tuners tell me that Castrol edge 10-60W is the what they recommend.

Any thoughts on this oil?

I have been using the Nulon 10-40W for roughly 3yrs would it be worth while changing?

[Wenier]

aiboart that is an awesome explanation. Always wondered what is the best way to explain it to people. The Castrol edge 10w60 should be a full syn oil but would be for someone giving the car some very spirited driving that is what the 60 part is for.

I give my ute some spirited driving but not enough to warrant running a 60. I personally run a elf 0w40 (might be 5w40).

What you've got to remember is the engine is designed for a certain viscousity oil at a given operating temperature.

In my case of the 0w40 it means that the actual viscousity of the oil starts off when cold is closer to the operating viscousity so doesn't have as much change to make it to this ideal operating viscousity at 40.

But if I were to be doing trackdays or something that will create that prolonged extra engine temp you will find the 40 will become too thin at that higher operating temp which is why you should up it to a 50 or 60.

[Kroozin]

I might go with the 0-40W aswell. The temp needle usually sits just under the 1/4 mark when cruising around which is what I do most of the time..I'd be lucky to give it a stab in say 2 gear changes once every blue moon. Thanks for that

[Wenier]

Were you meant to say under the 1/4 mark or over as under is low. My stock ute gets to bout 1/2 way between the 1/4 and 1/2 mark and when you give it heaps it'll go to the 1/2 mark.

[Kroozin]

Yeah just under a 1/4 the fans are dialled in for a 72degree stat though. When giving it a hard time for abit the temp will go just under half way.

Ill speak to bta about on wednesday another tuner recommended the 72stat the last time it was tuned. On a reallycold morning itll sit like around 3/4 of the way to the 1/4 mark when cruising at a consistent speed

[TonezXR6T]

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