Are fuel additives needed for diesel engines

[thunderhoof]

I suggest you check all the flexible fuel lines for cracking by bending them near the fittings. Any air leaks on the suction side of the lift pump could be a real problem. (I know from experience.)
Also I found on an older sailboat that a long horizontal run from fuel tank to lift pump was clogged with something nasty that appears to have built up over the years.
Carefully inspect your Racor filter after a few outings. Sediment or bacteria in the tank may not be picked up at first but after a few good sailing days it may break loose. You might need to have your fuel polished.

[Len hornick]

Another view,
The first i heard of the low sulfur was in Tahiti about 10 years ago ,a couple of boats had injector pump failure that was attributed to the change in the fuel.
Arrived in NZ and bought a Toyota land Cruiser Diesel .A few weeks later it started leaking fuel.. Took it to the Diesel pump/injector service co. They told me "sure we can fix it,but there are 20 ahead of you" Repaired at a cost of over 1000nz$ There was a lot of engines damaged here as a result of the new low sulfur fuel...Hmm.They told me put 2cycle oil in every tank,I have for the last 10+ years (same Toyota) runs fine , Did the same to the Ford diesel in my boat , about 4 ounces per 20 L also biocide.
Engine has 6300 hours starts instantly ,No fuel issues .

[FULLCIRCLE331]

If you have ValvTect fuel in your are use it, it has all the additives marine diesel needs. Just add a little conditioner for winter layup.

[Lepke]

I've been running diesel engines since I was a boy and I'm near 70 now. I don't come from yachting, my background in commercial boats, tugs and ships. I also had experience with returning mothballed ships to service. Sometimes with 20 year old fuel.
Tanks will always collect moisture. Period. If you have good filters and turn over your fuel often. moisture isn't a problem. Fresh fuel has enough biocide and stabilizers for short term. Weekend users and others that leave the vessel for months will have water and sludge. If they have a good filtering system it will remove most of the water. I use an additive every time I add fuel and know for a fact, my tanks are clean. No sludge, no water. I've walked around inside.
Circulating the fuel with a proper additive and a filter change will clean your tanks. I've done it many times that way. Big diesels pump a much larger volume of fuel than is need. Usually 10s of gallons a minute is circulated while the engine is running. Smaller engines need a circulation pump that pulls thru the primary filter. By circulating your existing "bad fuel" with a 3x dose of a good additive will clean the tanks. A vacuum gauge after the primary filter but before the pump will show when the filter is getting dirty. The additive will also improve the burn of the old fuel. I use Archoil AR6200. 1 ounce treats 80 gallons, but I'd triple the first time. Used in normal fuel I get about 10% better mileage. Oh, and the 20 year old fuel I mentioned earlier was better than the crap sold today. So having an additive that helps the burn does make a difference.

[evm1024]

I recall that there was a test done on fuel additives for lubrication. (engage google) Turned out that adding biodiesel was tops.

Lubricity Additive Study Results - Diesel Place : Chevrolet and GMC Diesel Truck Forums

and others....

[GarthGregory]

Diesel in Europe ( Med ) contains a high percentage of bio diesel , this seems to facilitate the growth of Algae etc . The low cost of an additive to stabilize your fuel is far easier option than cleaning your entire system , including taking your tank out , all of which I have had to do , besides the risk of your engine dying in a critical situation , that may cost you your yacht Rgds Garth Gregory