Marvel Mystery Oil

[Ribbit]

I like this stuff - Mobil Delvac™ 1300 Super.

It's compliant with the right things for older diesel engines.

Volvo VDS-4, VDS-3, VDS-2.

If I remember right, the usual recommended spec for older marine diesels, is VDS-3.

Walmart has a good deal on 5 gallons: Mobil MO01305P 5 Gallon 15W40 Super Diesel Engine Oil - Walmart.com

Perhaps the most critical issue to address though, is modern low and ultra low sulphur diesel fuel. Particularly perhaps as 'dodgy sources' can substitute central heating oil. It's a bit late to find out when the lack of lube has totalled your injector pump.

From now on I'll be adding 1/4 ltr of synthetic 2 stroke oil, to each 25 ltrs of fuel. 100:1 mix should work fine to lube the pump, and perhaps supply enough lube for valves as well.

[hellosailor]

Well, if it is an old engine running conventional motor oil, then yes there will be sludge (coke, tar, whatever you prefer to call it) on the valve cover and other places. That's one argument in favor of synthetics--they just don't tar up the same way.

But if you've had no problem from the tar (sludge) and aren't worried about it, there's no reason to run a "cleaner" in the engine.

I know some old mechanics used to add a quart or more of kerosene, run an engine (not under load, just static) to circulate that as a cleaner, then drain and change the oil. And MMO has to be gentler than that. It has many fans but I've never heard any loud complaints that "MMO ruined my engine" although I'm sure a web search could find at least one.(G)

But cleaning an engine just to support a newly installed oil gauge? Seems pointless. If there's a real sludge problem, in theory a clump can break off, clog an oil passage, and cause an engine failure. If that thought keeps you up at night, well, time to reconsider synthetics after the cleaning. If not, no problem.

[cards26]

I can save you some money on Marvel Mystery Oil. Get some light weight mineral oil, throw in a bottle of fuel injector cleaner, then add some red dye, and you're good to go.