Thread: What engine oil do you use ?

Originally Posted by jerryd

I was going to enquire what oil most people use, so this is an interesting subject. I've been using just a cheap oil and changing it frequently although next time I'll probably try the Castrol RX Super as it seems a popular choice.

While on the subject my County has a bypass filter fitted also, should this be changed each time along with the main filter ?? The last time I purchased filters the guy said I could just use 2 standard filters and not bother with the larger one Is this good advice ??

Can someone explain the soot levels bit ???

That person has given you bad advise

The full flow filter can not filter out the very small particles because it would restrict flow too much with a small micron filter element.

The bypass filter is there to capture the small particles. So it needs to have a small micron filter element. There is a flow restrictor in the port for the bypass filter so using the same element as the full flow filter will not achieve much filtration.

If the small soot particles are removed, oil change intervals can be extended. But it is best to use oil analysis to determine when to change it.

I have changed the stock bypass filter to a centrifugal unit that will remove smaller particles than the smallest micron bypass filter elements.

QDS $102-50 or $98 if you buy 3 drums.

Originally Posted by isuzurover

I do oil analysis, and only change it when the soot levels get high enough. On that note, we have just developed a new method of soot analysis, which is significantly more accurate than the current ASTM method. I can disclose details to anyone interested once the publication is released.

Congratulations on the new improved method and publication isuzurover.

There are many variables that alter the rate of soot buildup, but what sort of mileage range does the soot analysis show to be acceptable before changing the oil?

At say 10,000km is the oil always comprimised, or have you been able to get say 15,000km with more conservative driving?

Castrol RX Super - 5000k changes, zero oil consumption, very happy with it.

CHT

Fuchs oil, changed 5-10 000km depending on use. filter every 2nd change. It normally does not get started unless it has a minimum of 200km drive (To work) or driven all day on treks and staying hot. No oil use yet.
When I had to pull it down, not a drop of gum or build up anywhere

Originally Posted by nice1guv

Congratulations on the new improved method and publication isuzurover.

There are many variables that alter the rate of soot buildup, but what sort of mileage range does the soot analysis show to be acceptable before changing the oil?

At say 10,000km is the oil always comprimised, or have you been able to get say 15,000km with more conservative driving?

I don't have reasonable stats post turbo, and am about to fit a bypass filter...

However when it was NA, soot levels got to about 1.3% by 20k km. There seems to be a lot of debate about what is acceptable. Smaller diesels owners seem to think >1.0 is high, however many heavy diesels don't have the oil changed till >3.0%.

My 10c Worth,

Since landing in NQ on the advise of the local Landy Guru I used 2 sumps full of Penrite HPR Diesel. Wasn't happy and could no longer get hold of the Penzoil MA 15w 40 Long Life that I used to run.

On advise from Dave (BLKNGHT) Friday night I did a change n used Nulon 15w 40 Semi Synthetic for Diesels.

Did 250k with the boat on yesterday and its heaps better.

It wakes up n gets outta the sump quicker but still keeps the rattles down even @ an Exhaust temp of 580c

So I'll buy another drum.

Originally Posted by isuzurover

I don't have reasonable stats post turbo, and am about to fit a bypass filter...

However when it was NA, soot levels got to about 1.3% by 20k km. There seems to be a lot of debate about what is acceptable. Smaller diesels owners seem to think >1.0 is high, however many heavy diesels don't have the oil changed till >3.0%.

From what I've been told, soot condemnation limits vary according to engine families and this can only really be determined by using UOA and working with the engine manufacturer and oil blender, something none of us can do.
Basically some oils can tolerate far higher levels of soot than others without engine wear, as do some engines.

My oil analyst always reckoned i had too high levels in both the Patrol and 300Tdi and yet neither ever exceeded 1% IIRC, with the patrol never exceeding 0.8% at 20,000km.
As Ben said, some operators use up to 3% (with the manufacturers OK) as the condemnation limit in the large over the road trucks, and usually it's the Fe that determines the oil change, not the soot these days in these vehicles using the synthetic oils, particularly when using centrifuges for the by-pass filter.