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How to Do an Engine Oil Analysis

1K views 9 replies 4 participants last post by  BigART 
#1 ·
#3 ·
While I agree that UOA's can be a good tool to check out the condition of your engine( I do them myself )that article is typical of the ones you see on car repairs that only get it part right or just gloss over it all without giving true detail.

You do NOT want to pull the oil filter and take your sample from there as they suggest however. NO NO NO! That will give a false reading as the oil in the filter will contain more residue, debris, "bad stuff", etc... The dirtiest oil in your engine is in the filter and at the very bottom of the oil pan.

Using a vacuum pump works but you have to be careful you don't put the tube too far down and actually suck right off the bottom of the pan which is bad( sucks up crud that has settled to the bottom of the pan and that doesn't circulate with the oil ).

To recommend getting your oil from the filter though? Come on! There is also little to no mention of the fact the oil needs to be at operating temp and that the engine needs to be run for another 10 minutes or so after temp is reached to burn off moisture and or fuel in the oil. Never take an oil sample cold nor right after starting the vehicle. Always with it at operating temp and then a good 10 minute run after that.

To take a proper sample from the pan( non vacuum )...

1 - Drive your vehicle until full operating temp has been achieved and then give it 5-10 minutes more. This ensures any moisture or fuel in there from sitting/cold start will be gone. That way if any shows after the test you know it is a problem and not normal.

* - if you will have the sample pulled by a mechanic at a shop vs doing it yourself make sure you arrange it so when you arrive the vehicle is at least brought in to the bay it will be worked on in right off so it doesn't sit and then get started up after it cools down. Leave it running while you go in to tell them you have arrived. If it sits in the lot and cools down it must be taken out and driven again before taking the sample or you risk a false report.

2 - Once on the lift( or ramps in the driveway )remove the oil pan drain plug as you normally would. DO NOT take your sample right away! Let approx 1/3-1/2 of the oil drain out 1st. You want your sample from the middle of what is in the pan. Never take it from the 1st or last bit out as it can contain higher levels of contaminents from the bottom of the pan which give false readings on the report.

3 - Once 1/3-1/2 of the oil is out reach in with a clean container and let about a cup of draining oil go into it. Don't put the plug back in and take it out to get the container under there. Just reach in.

* - very important NOT to bump anything under there and knock dirt, grease, etc... into the sample or it will skew the results. Be cautious and just get draining oil!!!! Be careful wiping the lip of the sample container. Use a clean rag that isn't all frayed. Make sure your sample container is CLEAN! I actually go to the hardware store and get a quart sized plastic paint jug and one of the plastic covers for it. Costs about $2. Once the oil is in I carefully wipe the lip and then seal it with the cover instantly so nothing gets into it.

4 - Fill the oil sample container from the lab you use, again being careful not to get anything else into it, and send back to them per the instructions.

It is critically important if you want the most accurate results to keep all contaminants out of the sample/sample containers. It is also critically important that the oil be at operating temp and that the engine was run for a good 10 minutes after temp is achieved before sampling.
 
#4 ·
I have one small issue with the above, sorry NHEMI.

If you let 1/3 to 1/2 your oil drain out then the oil analysis is not going to help you extend your oil changes that way. Otherwise it's fine.

There is a small vacuum pump that AMSOIL and other companies sell. You can take samples from the dipstick tube. It has a long line that just snakes down the tube. You give it a couple pumps and it will use vacuum to suck the oil into a small sampling bottle.

Where ever you decide to take the sample you should do it from that spot every time so you do not skew your results from test to test.
 
#6 ·
quote:Originally posted by BigART:

If you let 1/3 to 1/2 your oil drain out then the oil analysis is not going to help you extend your oil changes that way. Otherwise it's fine.
That is the recommended procedure from the UOA lab's? You let some of the oil drain and then grab the sample. You don't want the 1st oil out nor the last oil out. The 1/3-1/2 of the oil was my suggestion and how I do it but the basic principle is the same. The whole point is to avoid getting a false reading from contamination/sediment on the bottom of the pan. That sediment will be more likely to come out with the 1st of the oil to drain and the last to drain. The sediment does not actually mix with your oil and travel through the engine as it runs so if it gets in your sample it contaminates it and skews your results.

I fail to understand why you feel sampling the "middle of the oil" will not provide an accurate measure for extended OCI's? It is how it is done and is the recommended procedure even from the UOA lab Amsoil recommends/uses( Oil Analyzers ).


quote:from Amsoil:
Collecting a clean and representative oil sample is critical to the oil analysis process. Put simply, an oil analysis is only as good as the sample taken. The accuracy and reliability of the data produced by an analysis hinges on receiving a representative sample from the equipment to be tested. To assure that the sample extracted is representative of the system, always follow proper sampling procedures.

See more info at: http://www.oaitesting.com/
Here is the info from Oil Analyzers which is where the Amsoil site sends you for more info on proper sampling procedures....

quote:From Oil Analyzers:
3. Oil Drain Method
Clean the area around the drain plug thoroughly to avoid sample contamination. Allow oil to drain for three to five seconds prior to catching a sample. Place a clean, dry sample bottle in the oil stream and fill to within 1/2 inch of the top. Seal bottle tightly. Wipe bottle clean.
Two other UOA lab's...

quote:From Blackstone:
1. - If you're taking your sample while changing the oil, let some oil drain before you fill up the bottle. Try not to get either the first or the last oil out of the pan.
quote:From Analysts, Inc:
Clean drain plug area before sampling. Do not sample the first oil out of the drain.
 
#7 ·


That's understood and I agreed with you on that. I'm not contradicting the method, but explaining there's more ways then one.

Let me add something so you understand what I'm saying.

It's hard to do it the "drain plug" way if you're going to extend your oil drain interval with that method. That's why I mentioned sampling through the dipstick tube.

Also, for those running by-pass kits. You can add an actual sampling valve to take samples from. This what I did with my previous truck. I ran oil analysis at 1000 miles, 5000 miles, then once a year. I went 3 years and 35,000 miles on one oil change. Only reason I had to change then was because the oil's viscosity was higher then spec. Read closer to a 40 then a 30. AMSOIL's PAO oils get a little thicker over time which is much better then getting thinner, breaking down and causing sludge.

Hope this info helps you guys out.
 
#8 ·
One of the sampling valves.
http://www.amsoil.com/StoreFront/images/BK30_300px.jpg">


The sampling pump.
 
#9 ·
I see the point now. You mean to test for extended OCI's as in test the oil in there at the time and wait for the results to come back to see if it can keep going or needs to be changed. I agree my method makes no sense for that. For that a vacuum pump is probably the easiest way.

I have always done the extended OCI testing by picking a figure to start out at( say 10K )and then grabbing a sample of the oil during the change and sending it off for a UOA w/ TBN test to see how it held up. It will show you that the oil was pretty much done by then or had life left. If it had life left you can increase the OCI to say 12K next time and test again to see how it did. At some point you can see how your engine responds to that particular oil and you get an idea how long it can go.

I forget some people will sample the oil and leave it in there until they hear back. That is why I couldn't understand what you meant. MY error.
 
#10 ·
No problem NHEMI.

My background and schooling lead me to do an initial sample at 1000 miles, then at 5000 miles at the recommended drain intervals. I got my baseline of the oil and continued to do it every 5000 miles for the first year to see how the oil was trending. After that I tested once a year.

Don't just look at TBN though. My TBN was still okay at 3 years and 35K miles. The viscosity was higher then spec'd for the 0W-30 I was using. All other tests shown the oil was still good. In fact, I could have continued to use it. But as long as I follow the recommendations of the oil analysis, AMSOIL backs it up with their warranty and it cannot affect my manufacturers warranty because I have proof of the oils quality.

I have yet to put a by-pass on my diesel. As soon as I do I'll be doing the same testing to see how far I can go between changes.
 
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