Pulling Oil Sample for Analysis?

[Israel Hands]

Looking at a boat this weekend.  How much oil is required to send off for an engine analysis? Is there a recommended way to pull a sample? Does the engine have to be run/warmed up beforehand? This boat is winterized and on the hard, so maybe now is not the time to do this. But if I could draw a meaningful sample, I might go ahead and do it.

 

[European Bloke]

If the engine has been winterised they may have just changed the oil. If they have I'm not sure what an oil analysis will tell you.

 

[suider]

I would agree with the above that it isn't the ideal time to do it- we will usually pull the sample as we are winterizing. Our sample cups are probably 6-8oz or something like that, and we have a separate vacuum pump that accepts the cup- and, yes, we happen do our sample pulls warm. We also use new tubing each time to avoid cross contamination.

All of that being said, even one sample is unlikely to get a 'definite' response of anything- most like to look at 'trends' and the first sample, even if something is noted, will usually come back with a 'will compare results next year' type of disclaimer. I use ALS Tribology and I like their setup and ease of accessing the results online.

 

[Zonker]

Yes, engine has to be run and warm. Heavy particles you want to know about will have settled in the oil pan otherwise. About 125 ml or 4 oz is about a typical sample size

 

[climenuts]

Playing devil's advocate here:

What sort of information do you get back from these tests and how does it translate to actionable maintenance to be undertaken?

Do you just get a breakdown of the allowable/actual concentrations of various materials? How would that be used to know you need to check bearings or you've got low compression?

How is Joe Blow  going to actually use these reports to prevent failures beyond what the regular maintenance he's already supposed to undertake will?

 

[Elegua]

Fair enough. Oil analysis only tells you history, but it does a lot to tell you the state of health of the engine. 

A good oil analysis will be pretty detailed.  In the analysis I attached you can see the engine breaking in at the start and then stabilize. The overall higher copper levels are from the cooler. But when soot climbed all of a sudden, as did chrome, which is an important wear metal on all of the hardened parts, then I knew it was time to look at my cylinder bores. Turns out the compression is fine, so I think that the engine was given a rough first start-up after being laid up. The rings can stick when laid up and if the engine is just started up without lubing or barring it over first it can be hard on it.  Well, that's my theory. 

 

[ghost37]

Playing devil's advocate here:

What sort of information do you get back from these tests and how does it translate to actionable maintenance to be undertaken?

Do you just get a breakdown of the allowable/actual concentrations of various materials? How would that be used to know you need to check bearings or you've got low compression?

How is Joe Blow  going to actually use these reports to prevent failures beyond what the regular maintenance he's already supposed to undertake will?

In addition to metals reports also flag whether fuel, water, or antifreeze has diluted the oil, all of which could indicate a number of issues. It's an easy way to get a heads up that something is wrong before it goes boom.

 

[SASSAFRASS]

If you are in Seattle stop by Covich and Williams.  I think the sample kit is $5 or $10 for chevron products but they will do others.  Small sample bottle and postage paid mailing kit. Will get analysis back via email.  Lab is in Portland so quick results.  Just warm engine and pull some oil from dipstick or oil change pump.  Probably pull a quart let settle some and fill sample container from that.  Will need some hrs on the oil for it to be worth while.

Red flags are fuel, water and metal content.  Report does it for you super easy to read.

Avoid a low sump sample point as it will most likely give a false report.

 

[LionessRacing]

A single sample should be thought of as qualitative. Only red flags matter, things you would decide to NOT buy the boat because of. You do want to have it taken warm, and buy someone you trust. Being on the hard is no problem to run for a few minutes to warm up. 

 

[Israel Hands]

Only red flags matter, things you would decide to NOT buy the boat because of.

Okay, well that would definitely be my reason for doing the sample - looking for major or pending major engine problems pre-purchase.

 

[El Borracho]

I agree...an oil analysis is only meaningful with careful comparison to a long history of tested samples. For example, if the lab reports chromium in the sample what can one determine from that? Yes, chromium is an indication of certain normal wear. But how much in the sample make an issue. It will always be present and is very much dependent of hours run, filtration, and how the sample was acquired. On an old engine the chromium will have substantially worn away. Will the low reading give one confidence, or dread? Same with bearings: when new there must be a great amount of babbitt in the oil, then a moderate amount during normal wear. Then progressively less as the babbitt disappears to expose the bronze (?) when the engine is worn out. Coolant, fuel and soot in the oil is more than obvious, no?

A proper compression test, and visual inspection, is far more telling. Actually, I would assume a decades old engine that looks tired probably is. Some future rebuild or replacement should be figured into one's costs.

 

[SASSAFRASS]

For a purchase a oil anylisis is good even without history.  Fuel and water will be the obvious no go's.  Engine will run with both issues and a owner may be completely unaware of leaking injectors, oil cooler etc.  For long term bering wear etc yes you would want a history but you can eliminate some of the major stuff with a sample. Just shouldn't be new oil.

 

[Elegua]

I think of oil samples as inexpensive circumstantial evidence that point towards or away from more definitive and expensive investigations. 

 

[MangoMan]

If you want to use oil analysis over time, it is a good thing to be disciplined with your sampling procedure. Do it the same way every time you pull the sample.

 

[El Borracho]

For a purchase a oil anylisis is good even without history.  Fuel and water will be the obvious no go's. 

There is always fuel and water in the engine oil. Without an accurate logbook and engine history the test is nearly useless. The report above shows the water going from perhaps 0.1 to 0.2....so what? From low to low. What is the buyer to surmise? That the engine is getting older? A great amount of fuel in the oil indicates either a relatively simple pump rebuild or an engine rebuild. Proper compression test and simple inspections are far more determinative in a buyer situation. Then @Elegua above dismisses the chromium test results with a compression test influenced wild guess (however reasonable). A guess that only time will test. An option a buyer does not have.

 

[SASSAFRASS]

I've been pulling samples for about 20 years in all sizes of engines, gear boxes hydraulic systems etc, there are red flags over night or sample to sample. They will have acceptable levels, areas of concern and critical immidate action.  For one time purchase it would the upper two to look at. Any critical content would be a no go, anything high would need a explanation.  Probably the biggest one is pin holes in coolers or high fuel content which could be alot of things and definitely a area of concern. You would be amazed at how contaminated things will still run.

I don't think I can remember a single progressive failure that turned up over time, but there were many that were fine to oh shit sample to sample.

 

[Elegua]

There is always fuel and water in the engine oil. Without an accurate logbook and engine history the test is nearly useless. The report above shows the water going from perhaps 0.1 to 0.2....so what? From low to low. What is the buyer to surmise? That the engine is getting older? A great amount of fuel in the oil indicates either a relatively simple pump rebuild or an engine rebuild. Proper compression test and simple inspections are far more determinative in a buyer situation. Then @Elegua above dismisses the chromium test results with a compression test influenced wild guess (however reasonable). A guess that only time will test. An option a buyer does not have.

Well it's not magic. In my mind oil sample analysis isn't definitive and just another tool in the toolkit. An accurate log of hours and maintenance so you know what the engine has been doing it a great help when it comes to diagnosis. It's much harder on these older analog engines. With cars if I I do a 4th gear "pull", see a "knock event" in the data logger and then see bearing material in the oil, I have a pretty good idea of what's happened.  Chrome is on all hardened parts and older engines don't have the oil galleries that new engines do so start up wear can be higher.  My CAV was leaking a bit, so that's off for a fix as well.  Injectors were perfect.  In my case the engine only has about 350hrs after a complete re-build, but it took me 10 years to put that many hours on. My electrical loads are low and I don't motor much. 

If you see contamination you can ask for a hold back to get you that extra time. My parents just bought a boat where the transmission oil came up a bit toasted. There is a hold back for the cost of replacement that will be released after a certain number of hours.