Motor oil

[Rook]

Rookie question. What weight of motor oil should I run in a 1969 280S? The shop manuals are vague and I can’t remember what I put in before (or how I decided it). Thanks in advance. I live in a moderate climate.

[Sugar Bear]

I'd use a 15W-40 "C" rated diesel oil for the higher ZDDP concentration because that is a flat tappet sliding cam type. Also don't delay valve adjustment on that motor. It will run better, prevent burnt valves and camshaft/rocker arm wear.

Motorcroaft 15W-40 adverts 1000ppm of ZDDP, that's the highest I've seen lately.

Good luck!!!

[Todd Miller]

Good tip on the Motorcraft. I'd heard it was the Delo or Rotella that had high levels of zinc in them still. I'll check it out.

[Mike D]

Motorcraft doesn't "make" oil. It is contracted out to varying refineries and which refinery/brand depends on which country you are in.

(https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3709020/who-makes-motorcraft-oils).

As Sugar Bear mentions, go for the highest level of ZDDP.

[g300d]

I'd also look at MB 229.5 oils.

Looking for oils for my flat tappet OM603 300D, and these are specced by MB nowadays. I was wondering why the gasser oil spec for diesels.

ZDDP was phased out because it doesnt play nice with emissions stuff. Newer oils have different stuff in it for that with the best current MB spec being 229.5, which also happens to be the current AMG spec.

There are a lot of modern AMG engines, like the M156 in the C63, that also have flat tappets.

If it will work for those engines, I dont think ours will give 229.5 oils a problem.

I do oil intervals at the original recommended for the car though. Our older engines may have fuel dilution issues that will wear out the oil more than usage will? Not sure about this yet, still looking into it.