Oil samples??

How accurate are these? I'm not so sure. Both my engines got flagged for x, y, and z earlier this year. Changed oil to mechanics recommended Chevron Delo 100 (had been using the NAPA oil) and took samples 35 hours or so later. Most of that time ran at 1800-1900. Suddenly they are "healed and healthy". No flags. Below are the old/new numbers.
Port
Iron 119-17
Chrome 6-1
Tin 16-1
Soot 50-30

STB
Silicone 24-20 (at 20 no longer flagged as an issue)
Tin 15-2
Iron 215-25
Chrome 34-2
Aluminum 35-2
Soot 56-26.

Tranny's show good. Generator (2003 13KW Onan with 1600 hours) shows sodium flagged at 221 and Aluminum flagged at 33. Oil (use Rotella synthetic blend) always looks great on the stick plus mid year I do a quick change without changing the filter. Generators cruise at highway miles unlike the mains running uphill everywhere they go. I really don't think there is anything to worry about. Samples are done by CAT.

Installing new gen this winter. Think I'll send a sample on that at 100 hours and see what they come up with. Thoughts?

My experience is the trend matters MUCH MORE than any single sample.

I agree with using the Delo 100. Not sure about the specs on the NAPA brand.

I would continue to sample and pay attention to the overall trend.

Oil analysis and results I have found out are in many cases up to the person doing the testing. When I lived in NC sent my Cummins samples to Gregory Poole the NC Caterpillar dealer who had a lab. Found out when questioning warning notes then next test perfect results that they had to build their own data base for my engines because Cummins wouldn't give them base lines for analysis. Basically the person doing the testing was left to his or her own interpretation of results. When I went back and looked at previous test results I found that on one test things were flagged as abnormal and next had basically same results and was considered normal. I've lost a lot of respect for oil samples results. I would recommend you really compare several tests and just compare results from at least three to set a pattern. Also use same testing facility so you eliminate as much variation as possible.

NAPA oil is NP75118 and rated for DD 2 strokes. Is the Delo that much better and samples are truly better? Cost is nearly the same and I only want to use what is best regardless of cost.

Quote:

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Originally Posted by JD5652

My experience is the trend matters MUCH MORE than any single sample.

I agree with using the Delo 100. Not sure about the specs on the NAPA brand.

I would continue to sample and pay attention to the overall trend.

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What he said and what the other gentleman said about how the sample was taken.
First the sample needs to be taken hot with all the stuff mixed up. Remember a lot of the metals will sink to the bottom of a cold engine and the sample won’t be uniform. Second the sample needs to be taken after the draining has started so you don’t get contamination off the bottom of the engine. Third the sample’s need to be taken on an exact time between samples to be effective.

What tools do I need to do the samples myself? Samples were taken cold after sitting a while.

Quote:

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Originally Posted by JD5652

My experience is the trend matters MUCH MORE than any single sample.

I agree with using the Delo 100. Not sure about the specs on the NAPA brand.

I would continue to sample and pay attention to the overall trend.

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The correct DD oil from NAPA P/n 75118 is a great CF-2 oil. I recall Amalie makes it.
Used and sold a lot of it.

During my shopping, I made an agreement with the local Mobil Oil distributor.
Now using Mobil Delvac 1240, thought to be the same oil DDC sells for their CF-2.

Of course Shell Rotella T1 is a great oil sometimes on sale at Wally World.

Quote:

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Originally Posted by madhatter1

What tools do I need to do the samples myself? Samples were taken cold after sitting a while.

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Cat makes a great SOS sample kit.
Each kit comes with a fresh draw tube.
Draw your sample when hot and not off the bottom of the pan.

https://www.cat.com/en_US/support/ma...-services.html

Were the samples taken at similar hours? IF one was taken at 100hrs and one at 35, that could explain the difference.

Different hours. I am learning that it is up to me to make sure filters are changed, samples taken properly, and monitor everything else. Even if you have a good mechanic you have to monitor all situations.