Old engine oil recommendation

[Dan2286]

Just would like to say, I did a search and I could not find the info I need. I am sure this has been gone over many times, but I guess I suck at searching.

I recently just picked up a running Olds 350 with less than 100,000 miles on it. I just replaced some basic things like timing chain, oil pump, and some gaskets. When I took the engine apart, I noticed that it is very clean inside with no sludge that I could see so I am assuming it was pretty maintained.

I was just wondering what would be a good oil for this engine? As far as I know, this still has the stock flat tappet cam and I am keeping it that way. I am trying to stay away from thicker oil because this engine will be started in cold temperatures. I was thinking a 10w40 would be the thickest I would want, but if anyone disagrees, please say so. I don't know how important zddp is in a stock engine like this, so if someone could explain, please do.

Thanks for the help!

 

[lipadj46]

Shell Rotella 5W-40 synthetic would be a good choice if you want to go with a 40 weight. If 5w30 maybe go with Mobil 1 EP.

 

[JohnBrowning]

If you are going to drive it dureing the winter Shell Rotela T SYnthetic 5W40 come warmer months a 15W40 would work well.

 

[bullwinkle]

Stick with a diesel oil-15W40 or straight 30 would work well in the summer, and 5W40 synthetic or 10W30 diesel oil in the winter. The newer SM rating has taken out the ZDDP & many other additives to "preserve" the catalytic converters-I'm personally trying to figure out how the old ones lasted so long (SARCASM!)!

 

[Dan2286]

What do you all think about Napa 15w40 premium fleet service oil? I had some sitting in my garage and decided to throw some in so I can prime the oil pump and verify pressure. I believe it is rated for diesel engines, but forget what rating it was. I think it was ci or something like that. If that is not good enough, I will just use it for when I get it in and first start it up then go to a different oil.

 

[sparkplug]

I wouldn't hesitate to use any Napa oil. It's re-branded Valvoline. I'm assuming their 15w40 is re-branded Premium Blue.

 

[JohnBrowning]

Rationg do not matter much between diesel and petro engines. A diesel oil will always be better built then an oil designed for a gasoline car. IN fact the more modern rating killed oils in some reguards. Sure they can not use the cheapest base stock avialble any more due to the decrease in allowed volatility but they also lowered the Anti Wear additives by 50% so that it would make the catalytic converter on your car last longer so OEM's could stop having to replace them under Wararranty. That did us no favors that is why 9out10 OTC synthetics are worthless and can barely make it to 7500 miles before their TBN is close to zero. It was not that long ago when automotive oils and diesel oils had close to the same additive package.

 

[Nickdfresh]

I would just use a good high mileage oil like MaxLife in the 5w30 for winter and 10W-30 when it warms up a bit...

 

[artificialist]

I see plenty of old flat lifter OHV engines doing fine on ordinary API oil. What they lack in ZDDP they make up for it with alternative EP additives.

 

[jorton]

The synthetic blends made by Connoco/Phillips are good cold climate oils. I would use 10W because it won't shear to a 20wt like 5W will. Brands are:

Motorcraft
TropArctic
76
Phillips66

 

[jorton]

Originally Posted By: jorton
I would use 10W because it won't shear to a 20wt like 5W will.


Dan that's assuming Oldsmobile spec'd 30wt and not 20wt for your year model.

 

[AntiMatic]

Dan, in my warmed over 72 350 Cutlass vert 4 speed, I have run a lot of dino 10w-30, 15w40 Delvac, and 15w40 Rotella (ZDDP). I now plan to try Syntec 5W-50 (AAP sale and $10 coupon). If its not rebuilt, I like the 40 and 50 weights. Main thing about an Olds is the poor oiling system. Don't use a high volume oil pump, as you will suck the pan dry. Also it wasn't designed to spin over 5000 RPM. I always shift at 4500 or below.

 

[Chris71]

Pennzoil Yellow Bottle 10w-30 or Pennzoil Platinum 10w-30 if you really want to treat her right.

 

[labman]

Give the starter a break and run 5w or a 0W synthetic. 30 will be good enough if it holds oil pressure. Otherwise, go to 40.

 

[jorton]

Originally Posted By: jorton
The synthetic blends made by Connoco/Phillips are good cold climate oils. I would use 10W because it won't shear to a 20wt like 5W will. Brands are:

Motorcraft
TropArctic
76
KENDALL