uoa - nissan TD4.2Ti

[jamie_m]

hey guys,
i just got the results of an oil test on my Nissan Patrol GU4 4.2 and while the diagnosis is normal i was wondering if someone can decipher and break it down a little more for me. i recently returned from an outback Queensland loop, did 4300km of mostly black top driving in quite hot conditions (40c+), i did an oil and filter change the day before leaving using delo 400 and ryco Z503 filters. i read a post before i went on the trip that stated that if not a drop of oil is consumed between services that a test should be done to see if there is an above normal fuel dilution, i have never had to add oil ever between changes at around 5000km but had the test done out of curiosity more than anything.

thanks guys
jamie

 

[jeremiah2360]

Can`t see UOA. No image and clicking on link requires membership to view.

 

[Quattro Pete]

Throw it up on photobucket or imageshack.

 

[jamie_m]

ah, sorry fellas, here is a photobucket link. the engine is a 4.2L 6 cylinder turbo diesel.


http://s1119.photobucket.com/albums/k640/gu_patrol/

 

[dnewton3]

Nice looking rig. Would be nice if we could get something like that here in the States.

Your UOA shows very nice wear; your wear metals are low, contamination is low, and TBN still very high. Nothing to worry about with that report. The oil and rig did well on your trip.

I see that you changed the oil. The numbers show that you oil can go much further than this. I would say you could add a couple thousand km's on the next one, test again, repeat and continue to build up the OCI extensions. Is the vehicle still under warranty? If so, that might be your OCI limit, depending upon your comfort with extended OCIs.

Just curious; what is the OEM OCI specification?

 

[jamie_m]

firstly thanks for the welcome. i've learned more about oil in 2 days than i did in the last 40 years.

the oem oci recommend oil and filters every 5000km. the vehicle is 6 years old now, i bought it when it was just out of warranty. i don't think i have made it to 4500km ever since i bought it 3 years back.

good to hear that all is fine in there and not wearing away to quick. i will try and hold back a bit on the next change and get a test at 6000km and post the results.


btw, you guys have some pretty tuff trucks over there that we don't get a crack at.

many thanks
jamie

 

[dnewton3]

5k km is akin to 3k miles to us, so that's a pretty darn short OCI.

Clearly that OCI duration is conservative in the effort to protect the engine, but I also suspect it's wasting the oil's capability. Extend out a bit, then test again. Repeat until you get to a point where you feel the ROI is met or your comfort is at risk.

Right now, you have plenty of wear protection and life left in the lube.

 

[jamie_m]

just another quick question. from a UOA, can one tell if the oil filters are performing as they should? can a filter comparison be made from a UOA?


jamie

 

[dnewton3]

Indirectly, but not directly.

If your soot and insolubles are low, there is an inference that the filters are doing their job.

Soot and insolubles are similar, but not the same thing.

As for insolubles, you're looking at oxidation issues and such. If your oil is in good shape, and not getting overheated, it should not happen too quickly. Oxidation is inevitible, but one can get "better" performance from fluids that resist oxidation well. Call the byproduct what you want (sludge, etc), it does happen to all fluids. The question is this; to what degree? Better oils resist oxidation better. The filter can only catch oxidation byproducts that become large enough to be trapped by the pore size of the filter media.

Regarding soot, one cannot ignore the massive effect that the add pack has (dispersents, in particular). As long as the anti-agglomerates are not overwhelmed, they are what keep soot small and segregated, and that in turn keeps the fluid viable. Until a soot particle gets quite large (comparitively speaking) it won't be caught by the full flow filter. If it gets large enough to be caught, it's been large enough to do damage as it grows.

One also has to think of this topic in two manners; size and percentage of presence. Think of this in a theoretical sense. Which would you rather have; one 7um soot particle, or seven 1um particles? Either way the total soot loading of the fluid is the same, but the 1um particles will have a much smaller propensity to do damage. And that 7um particle is not likely to be caught by the full flow filter until it grows much larger (perhaps twice it's size to 14um). So 'round and 'round it goes until it gets big enough be to caught. Versus having a good add-pack that is doing it's job, keeping fourteen 1um particles in check. Same total loading; big difference in size.

So a UOA really cannot give you the overall total view. For that, you'd also want a Particle Count analysis.

With that in mind, I don't think there is any fair ability to compare/contrast filter performance from one UOA to another. You can make some indirect inferences, but I don't see a direct link. Perhaps to a small degree for any particles large enought to be caught, but I don't want my particles to get that large in the first place. It is a an assurance that it will happen to some degree, the but less, the better.

To me, low soot/insoluble levels speak to the oil's resistance of oxidation, and soot control of the add pack.

 

[jamie_m]

awesome. you're a genius dnewton3.


jamie