10w-40 versus SAE40

[Garrie Denny]

I need to get some advice re oil to use. My old fiat 70ci states to use SAE40 oil in the sump, my question is will sythethic 10w -40 be all right to use in its place rembering this dozer is approximately 50 years young, any onewith semi-proffessional and knowledge would be really appreciated, thanks, Garrie.:notworthy

 

[willie59]

As long as it doesn't have a two stroke Detroit in it, multigrade oil would probably be suitable. However, and I could be wrong, but I don't think diesel engine oil comes in 10W/40 grade, least not here in the states. Diesel engine oil is typically a 15W/40 grade here.

 

[oldseabee]

I would have a discussion with your oil supplier to make sure that there isn't an additive that isn't compatible with the seals and gaskets in your engine. If they can't tell you check with Fiat factory product support. Most of the old engines had looser tolerences so when the engine starts cold the thinner oil is subject to bypass easier until the engine gets hot and the clearances close up from expansion.

 

[blitz138]

If it calls for 40 SAE 15w-40 will work. 15w-40 is 40 SAE the 15w has nothing to do with the weight of the oil, the "W" actually stands for winter. Multi-grade oils have a polymer that expands when the oil is heated and shrinks when it gets cold to keep the oil working as the viscosity is designated.

Tried to answer without getting to involved, let me know if you need more info.

 

[CAT793]

I would not run a synthetic oil in an engine that old. The viscosity would not be a problem but the ADD PACK, detergents and dispersants in a modern DEO SYN could promote oil consumption.

Rings and liner finish were not designed back then for the film thickness of modern DEO.

I would reccomend a Mineral oil.

 

[TheOldMan]

Does the non multi-grade modern oil apply to my 580C w/207 Case diesel? Presently using Shell 15W40.

 

[Nige]

I agree with my Austrailian colleague. Your engine was never designed for synthetic oils. Use a mineral-based oil in it. The 10W-40 you mention would most likely be for petrol (gasoline) engine service anyway. I've never seen a diesel egine oil of that viscosity, they are usually either 10W-30 or 15W-40.

If you can find a mineral-based oil that lists API CC or CD classification that would be fine - it was the standard back in the day. However I think you will struggle, most oils that you'll find will be rated something like CG-4, CH-4, or CI-4. So long as they are mineral based they will be fine.

 

[Garrie Denny]

Thanks to all who replied; I wet back and checked the container it is..... 10w-40 n0t 15/40 oil. Manufacterer is Valvolie, comes in 20 lTR PLASTIC CONTAIner, but with thanks to all who replied to my post I think I cwill drain the 10/40 and pay a bit more for the straight 40. and keep smiling. thanks Garrie.

 

[Nige]

Don't bother with a straight 40, it's 19th Century technology mostly designed for Detroit Diesel 2-strokes. A mineral-based 15W/40 in your Queensland climate will be fine. You should be able to get it from any good auto parts shop. if you want to stay with Valvoline then use their "J-Tech diesel engine oil". See here for link - http://www.valvoline.com.au/files/productpdfs/16.pdf - ignore the word Japanese, a high-ash engine oil will work fine in your Fiat.

 

[Garrie Denny]

Thanks Nige and others, Garrie

 

[blitz138]

Absolutely agree with Nige