Oil Analysis 101

The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.

firstbase

Guru
Joined
Nov 6, 2016
Messages
1,644
Location
United States
Vessel Name
Black Eyed Susan
Vessel Make
Grand Banks 42' Classic
I am right at 60 hours since last oil change which I believe is a good time to do engine oil and gear fluid analysis. However, I know little about where to get the kits and where to send. Everyone seems to use a different vendor most of which I have never heard of. alright, ALL of which I haven't heard of. Where is a reasonable place to get test kits and a reasonable, reliable place to send or take them here in South Florida-Stuart-Jupiter-West Palm area? I know to warm the engines and draw some first before getting the actual sample. Draw it out through the dipstick tube? Not even sure where to draw it out when changing the oil. Velvetdrives as well. Where do you pump it out?

I TOLD you it was Analysis 101... I think everything I post is 101 something or other:)
 
I do most of my oil tests on the road so local to me doesnt matter.

I use Blackstone labs as the personal write ups seem better than many others I have read.

I just do it every oil changes every 100 to 200 hours.

For 5 years it has given me confidence during my 2000 to 3000 miles every year snowbirding.
 
+ 1 on Blackstone,
I've used them for last ten years or so. Very fast email response. I print out results and log/file in a dedicated folder. Very good info for surveyors and potential buyers when ready to sell.
 
Blackstone as well - inexpensive, quick turnaround, personal comments on report.

I hope to catch any developing issues.

I also value having a stack of 100-hour analysis reports for the prospective buyer. It tells a story and adds value to the deal.
 
Thanks for the replies. I assume testing 1/2 way through the oil change cycle is correct?
 
Last edited:
I collect my sample about midway through the the drain at at oil change, which is 100 hours in my case. Blackstone asks on the submission form if I have interest in extended drain intervals, and I decline. Their website probably has much more information.

If you PM your email, I will share my most recent report.
 
Also very happy with Blackstone. I pull a sample and pump the oil out after a day of running to have a complete mixing of everything in the oil sump. I do it every oil change as it's easier to spot problems developing based on trends.

Ted
 
Unless the engine is a disaster a single sample is of limited use.

What you need is to start a library of all the sampling results over time, and oil use..

This will be very very reassuring to the next owner, as well as giving you confidence before the next long engine run.
 
Freds correct, the real value in oil analysis is establishing a baseline. changes in later samples will frequently spot problems before they become big issues.
 
I have done three samples in 3600hrs. Done at tail end of the oil change interval which is 200 to 300hrs. I don't see the value in doing it every time. Results come back normal and actually show the oil could be run longer than 300hrs. Spec for this engine is 250hrs and lab said the oil was good enough to run at least twice that.

When you get the results, look carefully at Na and K as those will flag if coolant or seawater are entering oil. Also look for fuel dilution as that can creep up on lightly loaded engines.

Soot content used to be the number that set the oil change interval, but with low sulfur fuel, soot generation is way down. And in trawler service and lightly loaded engine, soot generation is even lower still.

Low sulfur fuel also helps TBN from getting depleted as acid formation is reduced.

I think for most engines in our fleet the 100hr oil change is more often than needed. But the sample will tell you if this is the case.
 
That's what I am trying to do. I have one from 4-5 years ago and that is all. Gotta start somewhere. Ordered kits from Blackstone and will test when I get them to see what is going on. After that will test when I change oil every 200 hours as suggested in the manual. Figure that doing at the same intervals, same oil state is best so there is a commonality to them all but I'm a new guy, what do I know!
 
Last edited:
So, who here has found an issue based upon oil sampling and what did you do about it? :hide:

Granted, some engines are highly over stressed and do indeed have a limited lifespan, but a low revving Lehman or Perkins? Are you sampling transmissions and gensets too?

This question comes from a guy who has some hands experience with commercial engine oil analysis.

During my lower hour per year usage boat hunting forays, several mechanical things spark my interest. Particularly the maintenance log items and related adherence to schedules. Not to mention a peek in the ER. Now, on the 500+ hour per year commercial rated engines, oil sampling and analysis seems and is logical.

But oil sampling on a low hour usage diesel for sales purposes? Not sure how relevant this is to a knowledgable buyer. Nice looking oil samples on a vessel that overheats, inordinate exhaust smoke, coolant or RW leaks during a sea trial wouldn't sway me.
 
While oil analysis with every oil change may seem excessive, I pay less than $30 per analysis. For the average boater here, that's $30 to $120 per year (1 or 2 engines once or twice a year). In the overall cost of boating, that's nothing.

Ted
 
While oil analysis with every oil change may seem excessive, I pay less than $30 per analysis. For the average boater here, that's $30 to $120 per year (1 or 2 engines once or twice a year). In the overall cost of boating, that's nothing. Ted

But, aside from the feel good nature of oil sampling, what does it really accomplish? Not to mention lab or sampling mistakes that keep one awake on their low hour per year engine.
 
I agree that oil sampling is a hit or miss thing for buying a boat. To many variables and as sunchaser pointed out, sometimes one cant see the forest for the trees.

For others, especially long distance cruisers, my using sampling every 150 or so hours on an older designed, rebuilt engine with certain known design issues seems prudent.

It lets me know if fuel dilution or coolant or water is starting or increasing to an unacceptable amount. While it is still a personal decision what to do about it, but it allows me to think about when and where remedial maintenance may be done before having to stop because it has progressed too far.

Sure some of these failures are so sudden that analysis may be moot. However, after having a very slowly deteriorating head gasket issue, I like the comfort that I might catch something early. My head had been giving me warning signs for awhile (combustion to coolant, oil to coolant) but so minor for the fist year or two, certain tests were not definitive. Had it been any combination of issues affecting the oil, analysis may have stepped up my maintenance planning.
 
As a know-nothing-newbie I thought that learning everything possible about a boat was a good idea and analysis was one of them. More education taught me that the oil analysis is or can be a little misleading. At first I thought get a sample, send it in, get the report and it tells you what shape the engine is in. After more education I learned..not so much. I can see how trends would help me as an owner though. It did help me in a failed purchase though. Boat was what I would call forlorn. Nice boat but nobody had done much with it in two years. Got it to the survey and oil analysis stage and oil showed VERY high iron. Heard from the broker and others that it wasn't too odd with a boat that sat for extended periods. As the story goes condensation on the top of the engine/valve covers causes surface rust which drips down and then shows in the analysis. OK. They changed oil, ran the boat for 20 hours or so and retested. SLIGHTLY lower but no where near a normal reading. Backed out of that one as it spooked me and their plan to "fix" it by doing it all over again would take another month. I think in this case the oil analysis helped me out as the results were very whacked and the explanation and fix didn't quite go as planned. As a neb buying an older boat that is all it took. Beyond that I stopped paying attention to sellers who had one recent analysis to show. Despite their explanation who knows when and where it came from.
 
Last edited:
As a know-nothing-newbie I thought that learning everything possible about a boat was a good idea. The oil analysis is a little...misleading..I guess. At first I thought get a sample, send it in, get the report and it tells you what shape the engine is in. After more education I learned..not so much. I can see how trends would help me as an owner though. It did help me in a failed purchase though. Boat was what I would call forlorn. Nice boat but nobody had done much with it in two years. Got it to the survey and oil analysis stage and oil showed VERY high iron. Heard from the broker and others that it wasn't too odd with a boat that sat for extended periods. As the story goes condensation on the top of the engine/valve covers causes surface rust which drips down and then shows in the analysis. OK. They changed oil, ran the boat for 20 hours or so and retested. SLIGHTLY lower but no where near a normal reading. Backed out of that one as it spooked me and their plan to "fix" it by doing it all over again would take another month. I think in this case the oil analysis helped me out as the results were very whacked.
 
But, aside from the feel good nature of oil sampling, what does it really accomplish? Not to mention lab or sampling mistakes that keep one awake on their low hour per year engine.

Do you feel the same way after a yearly physical?

Ted
 
Unless the engine is a disaster a single sample is of limited use.

What you need is to start a library of all the sampling results over time, and oil use..

This will be very very reassuring to the next owner, as well as giving you confidence before the next long engine run.

+1 :thumb:
 
I think some peeps are missing the point. A single oil sample in itself may or may not tell anything about the current condition of an engine. a continuous oil analysis program CAN tell areas of the engine that may need further investigation. I don't think it needs to be done on a "every oil change" schedule, but regular oil analysis is valuable. Granted it won't head off a catastrophic engine component failure, but either will a blessing from your mechanic. Why do you think these tests are done by industrial fleet operators?, certainly the oil samplers aren't getting rich off of 200 hour a year yacht owners. Business that depends on fleets of trucks,boats etc do this because it works.
 
I have not done oil analysis in the past but I may do it with the new engine. Fresh start and all....
 
I think some peeps are missing the point. A single oil sample in itself may or may not tell anything about the current condition of an engine. a continuous oil analysis program CAN tell areas of the engine that may need further investigation. I don't think it needs to be done on a "every oil change" schedule, but regular oil analysis is valuable. Granted it won't head off a catastrophic engine component failure, but either will a blessing from your mechanic. Why do you think these tests are done by industrial fleet operators?, certainly the oil samplers aren't getting rich off of 200 hour a year yacht owners. Business that depends on fleets of trucks,boats etc do this because it works.

It does work, but commercial users tend to use it for different reasons. When I managed a fleet of Caterpillar 3516 driven generators, we took samples 3 - 5 times before every oil change. The main reason was to extend oil changes as long as possible. With a large engine, extending the oil change from 600 hours to 1000 hours meant a considerable savings in oil, manpower and downtime. Sampling occasionally picked up issues with coolant in the oil etc , but other more serious problems were usually picked up by vibration sensors, exhaust temperature monitoring immediately without the lead time of oil sampling.

For high end pleasure boats, a history of oil sample reports is probably a good investment, but more for the reassurance it gives any future buyer.
 
Last edited:

Latest posts

Back
Top Bottom