[roc]

Hi all,

Just had an oil analysis done, vehicle is a GU3 zd30 with 75k on the clock. Oil (Castrol RX Super 15W40) had been used for about 2800km prior to the test, results came back as:

Aluminium(ppm) 1
Nickel <1
Copper <1
Chromium <1
Iron 6
Lead 1
Tin <1

Silicon 5
Boron <5
Sodium <1
Potassium 1
Phosphorus 1180
Molybdenum 1
Calcium 2251
Magnesium 323
Zinc 1411

Water (%) <0.1
Soot (%) 0.4
Viscosity (cSt, 100degC) 13.9
PQ index <10
Oxidation (Abs) 10.8
Sulphation (Abs) 16.4
Fuel (%) 1
Dispersancy Pass
Total Base Number (by FTIR) 8.4


So, what does that all mean then?

 

[CARIB]

The first set of data is the wear metals in the oil. There is no significant wear in the engine, however you need to trend this information over time.

The second set of data is the additive metals in the oil. There seems to be no significant depletion, however the only way to be sure is to run an oil analysis on a sample of new oil. Basically the oil is good for further use.

The third set of data is the physical properties of the oil. There is 1% fuel dilution which is not too high for a diesel engine and the TBN is 8.4 so you could extend the oil drain interval. However, you would need to have a couple more samples analyzed before making the final decision on how far you can extend the drain interval.

Of course the cost of all these oil analysis would soon exceed the cost of an oil change!

 

[patrolen]

where did you get this done roc?

 

[Bruza 2]

The first set of data is the wear metals in the oil. There is no significant wear in the engine, however you need to trend this information over time.

The second set of data is the additive metals in the oil. There seems to be no significant depletion, however the only way to be sure is to run an oil analysis on a sample of new oil. Basically the oil is good for further use.

The third set of data is the physical properties of the oil. There is 1% fuel dilution which is not too high for a diesel engine and the TBN is 8.4 so you could extend the oil drain interval. However, you would need to have a couple more samples analyzed before making the final decision on how far you can extend the drain interval.

Of course the cost of all these oil analysis would soon exceed the cost of an oil change!

Good explanation Carib, but he's only done 2800km till the test.
Which makes me ask roc, why didn't you do it at 5k and/or 10k?

 

[GU Duke]

By taking amcouple of samples before your prescribed change interval, then another at the interval, you can analyse the trend, (in many cases oil degradation and contamination it is linear, but this should be verified through a MINIMUM of 3 samples). From the trend, the safe useful life of the oil can be predicted. It isn't uncommon (particularly in heavy equipment) to find oil can last for up to 5-10 times the perscibed interval without requiring change, as determined by ongoing condition monitoring. Particularly in heavy equipment where every oil change can cost thousands, a $30 lab analysis, or a $30K handheld, realtime analysis device can quickly pay for themselves, especially when you consider the cost of lost productivity due to maintenance downtime.

I'm not sure that it would be cost effective on a personal vehicle though, unless it was an occasional analysis with a focus on detecting engine wear (Ie metal particulate).

 

[bennoGU28]

If an engine is being run at a constant load / rpm then the oil life will be far longer but if the same engine is run with varying load and being accelerated constantly (especially on very laggy engines) then it will be having far more soot finding its way into the oil.

Marine engines used in trains or trucks are very hard on thier oil.

 

[roc]

Hi guys,

The test was carried out by Australian Lab Services (also called emonitor) and costs $30-35. The reason I got it tested at that interval was actually because I found some water droplets in my catch can and I thought the sludge in there had a bit of a green tinge. Made me think head gasket and after getting a negative CO test I thought I'd get an oil analysis to check water content of the oil for peace of mind- at <0.1 that's fine from what I understand.

Roc

 

[whitie]

Hi Roc, a couple of things stand out to me in those results.

The Iron is higher than what I am used to (I get around 4 in a 10k sample) and the TBN is 8.4 (it started out at 10.9).

The higher Iron reading could be caused by the formation of rust, the quick variance in TBN (if it was 10.9 to begin with) is also usually a sign that something is going on as well.

Just keep an eye on it and maybe get another analysis done at 10k interval to see if anything stands out then.

Cheers,
Whitie

 

[roc]

Thanks for the replies guys.

Whitie - the higher iron being caused by rust is very possible - before doing the 2800km the vehicle had actually been left standing for about 3-4 months so a bit of rust is very possible.

I've been doing a bit of searching for other oil analysis results for zd30's on this site and the 3 readings (3 different vehicles/oils) for iron were:

test at 10,000km 8
test at 5000km 12
test at 4767km 21

The base number is the lowest of any of the tests I've seen. I'll def do some more research and keep an eye on that figure.

Cheers
Roc

 

[q8160]

Oil sampling and what the figures mean ??

Hi, oil sampling is a great thing and can show up trends that will indicate a 'problem' before a 'real problem' (like a mechanical break down) occurs. ( but not always)

However can only be really useful if the sampling was initiated from zero hours to establish a base line for each metal, we need to know what and where the indicated metals live within the engine and sampling is carried out at same in service time, each time and preferable with the same lubricant.

Get a graph book, place the metal indicators down the side and time in service or when sampling is carried out across the page.... at each sample point, mark metal plots and join with a line from the last sample plot.

Having said all this, at 75k's you could make this your base line. Subsequent samples will then be used to show how your engine is trending. Any high rate deviation will give an indication that abnormal wear is starting to happen.... but if there is no correlation between what is normal and what is not normal, wear patterns/trends will have to be established over several samples.

If you know someone who has been trending their engine for several oil samples, from new, you could use their figures as a comparison base line ( wear rate).

With regards to the ZD30 engine, my assumption is that oils sampling / trend monitoring would not show up the 'grenade' type of failures we have seen.

Don't get me wrong... if this engine was running with the same pollution gear as the SD22 engine, no other engine in it's class would come close to it. It's one tough little son-of-a-gun.

My 2 bobs worth

 

[bennoGU28]

May I respectfully disagree, if a ZD30 was to overfuel through either a failing MAF or a partially blocked manifold it should start to show up through a higher soot concentration.

 

[q8160]

May I respectfully disagree, if a ZD30 was to overfuel through either a failing MAF or a partially blocked manifold it should start to show up through a higher soot concentration.

Agreed..... but wouldn't this would show up thru throttle responce, visible exhaust emmisions (soot output - black smoke) and at the bowser??..... long before a sample report was obtained, plotted and determined.

My 2 bobs worth

 

[roc]

Oil analysis update....

Hi all,

Just did an oil change and analysis at 8000kms and got the following back (8000km's is left hand column, 2800km's is right hand column). Only thing that seems to stand out to me is that the TBN is now down to 5.8. (Castrol RX Super starts at 10.2). I'll probably extend my oil changes to 10,000km now as (if the TBN reduction is roughly linear) it'll still be over 4.5 at that point.

Would love to hear what others read into the below.


8000km 2800km
Aluminium(ppm) 2 1
Nickel <1 <1
Copper 1 <1
Chromium <1 <1
Iron 9 6
Lead 2 1
Tin 1 <1

Silicon 6 5
Boron <5 <5
Sodium 2 <1
Potassium 1 1
Phosphorus 1230 1180
Molybdenum 1 1
Calcium 2382 2251
Magnesium 327 323
Zinc 1503 1411

Water (%) <0.1 <0.1
Soot (%) 0.5 0.4
Viscosity(cSt,100degC) 13.6 13.9
PQ index <10 <10
Oxidation (Abs) 10.7 10.8
Sulphation (Abs) 15.6 16.4
Fuel (%) 1 1
Dispersancy Pass Pass
Total Base Number 5.8 8.4

Cheers