Is diesel oil always black instantly?

[JOHNMARDALL]

Old fashioned high sulfur fuel also contributes to the engine oil going black quickly. It you've inherited a tank full of the stuff, things will probably improve when you use or recycle it and refuel with low sulfur diesel.

Good luck
John Mardall
Vetus Maxwell Group.

[boeing1]

all the boat that I had and even worked on after a oil and filter change the oil does not stay clean long.

[elschwieb]

The oil in our Westerbeke 5BCD genset turns black on first running (we used RotellaT). That has about 1300 hours on it. Our Perkins 4.236, with about 3000 hours, runs clean for about 75 hours before it starts to darken. I have been told that all Westerbekes run black, but I cannot say from personal experience.

[basssears]

Takes about 20 hours for it starts to darken in my (unknown hours, ~3,000 prob) Universal/Westerbeke 5432/M40.

Coming from cars I can't stand how few engines have a bottom drain plug, that's where all the nasty stuff comes out, and that's where the magnetic drain plug is supposed to catch all the little metal filings.

Best I have found for oil change is (not cheap) the Jabsco pump on a bucket:
Jabsco 17800-2000
It's a strong 12v motor, goes straight into the bucket so you don't need other containers until you have used your new oil, then easy to pump from the bucket into your old containers to go recycle. Use a real steel hose clamp not the dinky plastic one they provide (it can let the smaller hose pop off when you go to pump out the bucket, spraying oil everywhere), and zip tie something small and rigid (like plastic covered coat hanger) to the small hose to keep it straight so you can poke it way down into little cavities and suck up all the nasty goo. Bonus on this pump is so far it hasn't had any issues with doing pretty hot oil changes (hotter oil keeps crap suspended so it leaves the engine in the oil change). And the thing lives in a box in the dock box so it doesn't take up space on the boat.

-- Bass

[captmikem]

An easy flush, that works very well is after you drain your oil, fill it with diesel, start it and run at an idle for about 20 seconds, then drain it, put on a new filter and put your new oil in.

Gets rid of the oil that did not come out on the drain, and washes down all the passages, top of the head etc.

M

[basssears]

Originally Posted by a64pilot

Now, once flushed out if it's an older design, naturally aspirated engine, may well be that straight 30W or 40W will be every bit as good as the syn oil, and the money you save use to change more often, don't buy into that it's synthetic oil, you don't have to change it very often.
We change oil in our little Diesels not because it's broken down, but cause It's loaded with soot and soot is carbon, and carbon isn't a good lubricant

I agree, my personal opinion has been that synthetic is not worth the money here (although I love it in our newer cars). I don't like to let oil with all the acids etc in it sit over the winter, and I don't like to use oil that sat over the winter in case there's been condensation in it, so for us there's an automatic oil change in the fall to prep for winter (and that is rarely past the 70 hours I shoot for for oil changes anyway) and then one in the spring (usually with about 5 hours on it). I never get enough hours (at least right now) on the engine in a season to make it worth synthetic (commuter boating right now, trying to sail as much as possible instead of motor).

Another thing to do is have oil analysis done, I've used Blackstone and they seem very good, do it after you've done your flushes and then have some hours on the engine (a 5-10 hour oil change won't say much about what's going on)... the fall oil change always has an oil analysis done on it.

If you're concerned about the engine oil change interval, figure same issue applies to tranny and take a good long look at it too (and you can do oil analysis of that as well).

-- Bass

[lazydove]

I bought a brand-new VW Tiguan (one of the cheaters). The oil was pitch black after less than 20 hours of use. According to Volkswagen this is "normal". Less than 6 hours after an oil-change the oil is black.

[lazydove]

I bought a brand-new Volkswagen Tiguan (one of the cheaters). The oil was pitch black after about 20 hours of use and turns black a few hours after an oil-change. Volkswagen claims that this is normal.....but can we still believe those guys?

[lordgeoff]

[QUOTE=Guy;2433226]

Originally Posted by Stu Jackson

Engines are at an angle, and not all the old oil can be removed.

Ours is almost level and the drain fitting is at the bottom, it still turns black. There is a lot of residual black oil all over everything inside the engine, oil cooler, hoses, passageways etc. I could get our Perkins oil looking OK but I would need to change it every 25 hrs and I go over 100.

I change the oil in my M92 Perkins EVERY 200 hours. Use the pump attached to get most of the oil out into 1.5 Lt Chateau Plastique screw top wine bottles. Then take the Sump plug out and let it drain for half an hour. A purloined plastic container belonging to the admiral takes the remaining half litre or so. I change out the oil filter and give the engine a wipe over and check for anything loose.
The old filter goes into a triple bagged plastic bag. The Chateau Plastique bottles go into another triple bagged bag and gifted to the Marineros.
The engine takes exactly 7.5Kt. The oil stays clean for 100hrs then goes dark towards 200 Hrs. Would probably be ok for 300 hrs but the Perkins is always happy happy happy with new oil and filter. 7000 hrs on the clock.

[a64pilot]

If your concerned about magnetic particles, there are all kinds of oil filter magnets available, and they really do work.
There is even an FAA approved oil filter with a magnet in it, as an A&P I always cut open filters and inspected the media, and there would be little fine wear particles on that magnet.
http://www.aircraftspruce.com/catalo...ickkey=3020932

[a64pilot]

For those that have sideways mounted filters and would like to drain them before removal.
http://www.aircraftspruce.com/catalo...ickkey=3020932

Just make sure your filter is big enough or you will need to shim the tool

[Don C L]

I can't figure it out. My buddy had his MD7A rebuilt and he's run it about 20 hours and the oil has not turned black yet! Maybe we have found a new Bermuda Triangle or an anomaly in the space-time continuum!

[Pete7]

So does my VP2003. I use the cheapest supermarket oils providing they meet the API spec for the engine. It doesn't like semi or fully syn oils.

Pete

Originally Posted by sandy stone

I always expected my engine oil to turn black right away, as you say. But on my current boat, with a 1986 Volvo 2003 engine, the oil stays amber for months. I'm as surprised as anyone. I change the oil every year, whether it needs it or not, and I put a half quart or so of new oil into the crankcase while I'm sucking out the old oil. Maybe it helps, I don't know, at least I feel good about it. The engine internals that I can see through the oil filler port look absolutely spotless. I do use Rotella, and try to stay with Wix filters.

[Deltasailor]

Originally Posted by transmitterdan

For many older diesel engines it is true. The oil turns black as soon as you start after an oil change. But for newer engines with good rings and tight tolerances it is not always true. My Yanmar 4JH3E with 2K hours has clear oil on the dipstick. But each year the oil i pump out of the bottom drain valve gets a little darker. Still it does not go instantly black like a lot of diesels do.

I had a Perkins 4108 in my Endurance 37. As soon as the oil was changed it was black. However the oil in my Jeanneau 37 Yanmar you could cook chips with after a year! Clean as a whistle.

[Deltasailor]

Originally Posted by lazydove

I bought a brand-new VW Tiguan (one of the cheaters). The oil was pitch black after less than 20 hours of use. According to Volkswagen this is "normal". Less than 6 hours after an oil-change the oil is black.

I've an Audi TT Quatro turbo ( A Cheater) Oil as clean as a whistle!