The Offshore Voyaging Reference Site

An Easy Way to Avoid Engine Failures

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There are few things that will ruin a cruise more than an engine failure. But worse still, a sudden engine failure can result in the loss of the boat, or even a life.

There are tons of books and articles on how to properly maintain an engine, but the one tip I never see mentioned is to get the engine oil and marine gear fluid analyzed regularly, something we have been doing for nearly 20 years.


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Marc Dacey

It’s a good suggestion, just like installing an EGT is a good suggestion. But very few will follow it (well, maybe more readers of you here will). I’ve seen racers kill diesels in five seasons here on Lake Ontario because of their habit of redlining a cold block to the start line in 10 minutes, and then doing it again after the race. The basic needs and proper use of a diesel auxiliary seems to be misunderstood (or ignored). Really, club racers should have some sort of updated, low-compression *gasoline* auxiliary, like the Atomic 4. You can run those on and off all day. Imagine what you’d save in oil analysis!

Drew Frye

Makes sense. I’ve run such programs and supervised the labs. While you’re at it, add periodic coolant testing for glycol cooled engines. Even trace contamination with seawater (20-50 ppm is the condemning limit for chloride) can raise considerable mischief. This is why extended coolant change intervals, common for cars and trucks, don’t work for marine engines.

Testing helps anticipate and prevent serious mechanical failures. However, the most common sort of failure has nothing to do with wear. It is also the sort that happens just as a boat is negotiating a jetty or marina fairway. A filter clogs (you were just bouncing around), a line gets wound into the prop (dropped the chute and for got a sheet, or perhaps a dock line is hanging), or perhaps it simply stalls due to poor warm-up. I once had both engines stall between jetties because I had just changed the fuel filters and forgot to open the fuel valve when finished–I anchored really fast, avoiding harm).

In this case the answer is to allow the engine to warm up at the dock or at anchor before heading out, and to motor the last 1/2 mile when approaching a tricky entrance or jetty. No “jump in and go” or stylish dropping of sails right at the entrance. In this way, stupid, annoying failures happen in a safe place.

(It would be too embarrassing and lengthy to recount all of my dumb failures. Fortunately, none in this catagory were damaging and they have been effectively eliminated.)

Drew Frye

For outboards that tip-up you need to check the down-lock. They are notoriously unreliable until checked (once checked they are safe). Unfortunately, all seems fine in forward, but the moment you shift into reverse they just float up.

Eric Klem

Hi John,

You are certainly more disciplined than me to be doing oil analysis at each change. We have gotten analysis as part of the pre-purchase survey before but you have to trust the owner on how many hours it has been since the last change. I have also owned 3 diesel pickup trucks and have always used analysis to help me figure out what an appropriate oil change interval is for them (interestingly, it was way higher than I expected for all of them so I just change the oil once a year unless I have some very abnormal driving). For true voyagers, I would definitely think that this would be a good idea but I see less of a need for others who have better access to repair facilities. I do recommend doing more than simply looking at the oil level regularly, you can catch some major problems ahead of time by smelling and giving the oil a good look but it is a far cry from proper analysis.

Thanks for the tip on Cat having a service for this. I have always used Blackstone Labs and been happy.

Eric

Dick Stevenson

Hi all,
I agree with Drew about the occasional analysis of the coolant.
I test my oil once per year at the end of the season.
I started “sucking” my oil out into a vacuum container a few years ago which made collecting un-contaminated samples more difficult. My solution is to take it from my oil filter which is remote and easy to remove with all the oil still sitting in it: thereby easier to pour out a sample.
Don’t forget the genset. This is an area where an analysis of mine caught excessive wear in my fairly primitive beast and caused me to change oil weights.
I have used Polaris labs for no great reason, but they sound like they do the job.
My best, Dick Stevenson, s/v Alchemy

Bryce

Hi Dick and others,

I love how I always learn something from this site without having to go through pain for the lesson!

I thought it was a great idea taking the sample from the filter. A couple of follow up questions present themselves:

1. I change my oil filter less frequently than I change my oil (as per the manual). I assume that this is the same for most diesels, but my knowledge is limited only to my Yanmar. Do you change the filters each time you change the oil, or hold off taking the sample until the filter change?

2. Have you ever had a problem with grunge from the filter contaminating the sample?

3. Do you have any tricks for obtaining uncontaminated gearbox samples? I’ve just been using a clear plastic tube attached to a syringe commandeered from the med kit, but it is a tedious and messy process.

Cheers,

Bryce

Rob Gill

Hi Bryce, Dick, John,
Absolutely second your comment on this site, your questions and credit to Dick for his idea. I was also wondering about using oil from the filter – for clarity, isn’t this were the most contaminants are designed to be trapped and therefore might give an overly pessimistic view of the engine condition?
regards,
Rob

Dick Stevenson

Hi Bryce, Rob and all,
With respect to getting the oil from the filter, I figured the oil was well stirred up and distributed as the filter oil is quite hot. I suspect if you let the oil sit for long periods you might get skewed readings, but even then, I do not know. The analysis is looking at contaminants: metal, coolant, sea water and such, that are in suspension. I am also taking out a sample, just the first few ounces. I am not draining the filter. That said, it is a good question.
If there was any grunge from the filter, it would be on the bottom and not poured into the sample jar. I turn my filter over into a funnel to drain and, over years, have never noticed any grunge coming out and the oil looks the same as all the other oil. I suspect the “grunge” is captured by the filter element and held onto.
I change my filter every time I change my oil. I also change my oil at about 75-80% of the time the manufacturer recommends. Maybe if I were running a fleet of trucks and buying oil by the ton, I would look at ways to extend the time, but for me, the money, in the scheme of things, is not a relevant criteria (1-3 changes per season). For those with access to oil at US prices, this is even more the case.
As a note, my old engine was a Westerbeke with 100 run hours as the oil change mark. Once, in Central America, I had trouble finding oil and called Westerbeke about using a multi-viscosity rather than the straight 30. After a few minutes of inquiry about my motoring habits, they said to just keep going significantly past the 100 hour mark. Their rational was that I (and most cruisers) was much easier on my engine oil as I motor occasionally/regularly for long periods.
As for gearbox oil, I will mention a “tool” that has multiple uses on a boat. It is old fuel containers. They can be cut with a hot knife (I use a propane torch with an old crab knife rather than a lighter weight rope/canvas hot knife—empty and air the container thoroughly first) into any shape you wish to slip under (or hold) most anything. They are very strong and easy to clean (Think winch servicing). One of mine was made to slip under the tranny and is easy to clean so the tranny oil is uncontaminated. It also makes it easy to look for metal particles as the dump is out of the bottom of the tranny where particulates congregate. This inspection is actually all I do.
My best, Dick Stevenson, s/v Alchemy

Marc Dacey

Great minds, etc. I have used a large foil pan of the sort employed at Christmas under my engines for a similar purpose. It can be easily bent to shape and if you have a leak, it’s easily spotted and located.

Dick Stevenson

Hi Marc,
Agreed. For repeat tasks the old plastic fuel containers are great. For others, I keep a selection of throw away aluminum pans from any supermarket. They are light, easily bent and modified, and come in a variety of sizes. They are particularly helpful for containing such ugly tasks as plugged toilet fittings as, with a bit of patience, they can be duck taped to areas where you want a leak caught/contained saving much spread of yuck and clean up. They can also be molded into troughs and gutters for transfer of liquid from difficult to deal with petcocks and such to more convenient locales.
My best, Dick Stevenson, s/v Alchemy

Eric Klem

Regarding whether taking oil from the filter for analysis is okay or not, I would think you would need to test that to be sure but it would not be my preferred solution (people who work on filtration may be able to definitively say). You would be getting oil from both the unfiltered and filtered side. The actual unfiltered oil on its own is probably not that bad but if it takes some of the contaminants caught in the filter, that could skew your results. Oil flows from the outside of the filter to the inside so if you could carefully only take oil from the inside, you wouldn’t have any worries. Whether this is possible is probably installation dependent.

The first thing that I do when I get a new vehicle is install one of the Fumoto valves to make oil changes easy. These also have the advantage of making sampling easy if you have good access to the bottom of the oil pan. On our boat, we have a hose hooked to the drain plug hole which we can use to suck the oil out but could also be used to get a sample by simply disconnecting it quickly from its mount and holding it lower than the oil level.

Eric

richard stanard

would like to see comments for your related article on how to stop killing your engine with kindness but says comments are closed…seems to also block access to the registered comments as can’t see how to do that…i must be missing something? have an excellent day…i am…cant miss here in the islands although the wthr lately a little unsettled…hard to beat messing around with boats regardless of loca

richard s., s/v lakota