Packard Forum Index » Post-War (1946-54)

Just curious who uses what weight by region/season? Read some saying somewhere about using 20W50 or some such brew.

Been using 10W30 and have added a can of STP last time and probably will continue in Southern California in the 288.

I use Shell Rotella-T diesel oil here in western Pa.

I usually use Shell Rotella T in 15W40 grade or other diesel oil in 15/40 if on sale.

Shell Rotella T or Mobil DelVac, either in SAE15W-40 is my choice as well. If you can, get the now discontinued formula with the higher ZDDP levels; it's identified by having an API rating of CI-4 or CI-4+. Though it's been out of manufacture for some time now, I run across it frequently at the smaller auto parts stores. The additive package has been reduced in the current (CJ-4) formula due to catalytic converters on diesel trucks.

Gentlemen:
You took me by surprise with the use of Rotella.
Can y'all comment on why the preferred use of diesel lube oil in gasoline engine? Additives? Other issues?
Thanks.

ZDDP (zinc diakyl dithiophosphate), an EP additive, was greatly reduced in SM-rated oils for gasoline engines to prevent premature failure of contemporary catalytic converters.

Oils rated API CI-4 (and CI-4 Plus) for diesel engines had much higher levels of ZDDP, but with converters now being required on those engines, ZDDP is also reduced in CJ-4.

I suspect it won't be long before a great influx of oil products with higher levels of ZDDP become available for the collector car market.

Gee, don't think I've ever see those out here.

Both Red Line (a botique oil formulator) and Castrol have recently introduced additive-rich specialty oils for the (non-catalytic converter) collector car market. Red Line advertises in CCCA News Bulletin and other publications.

Thank you Brian and Owen.
BTW, I have a car buddy (races SCCA) who, upon advice from a race car mechanic, used Red Line to cure syncro problems in a Nissan Z car.
He had no 2nd syncro, replaced the oil, and in a couple hundred miles, he had a syncro again.
Strange, but true.

Guess I'll just stick to straight Valvoline 30 for warmer weather. Actually since it doesn't get below 60 when I actually use the car I could leave that in year round. Was mostly wondering how low you go in the frigid East.

Back in the 60s STP was experimented with for things such as gearbox woes and tons more applications so there is probably something to the Redline thing.