Please help - diesel tractor oil question - SAE 20?

[Breadfan]

All,

I'm trying to buy oil today for an old Ford Backhoe/loader. It's a '77 555 model. Has a 3cyl diesel. According to the operators manual, it takes 8qts of "SAE 20" oil.

If I buy 5w20 is that right?

I take it SAE 20 means 20 weight oil, so Xw20 would work, and I know I can get 5w20 (I think we know why!).

20w50 is not right as it is 50 weight oil, SAE 20 is 20 weight...

This motor is old, runs just fine though, I just got it running a few weekends ago. Want to buy oil and filter today.

Any help?

thanks!

[FordNut]

I would go with the recommended straight 20W

[Blackened300a]

If it calls for straight 20 then stick with that or even straight 30. 5w20 is too thin for any diesel.

[Breadfan]

Ok, thanks! My gut feel was 5w20 was too light. But then i thought the "20" referred to the weight and the 5 to viscosity changes in diff temps, thus equal to SAE 20. But I know how light 5w20 is and it didnt make sense an old tractor engine would have close enough tolerances to need such thin oil.

I think the FLAPS has a diesel oil section i will see what they sell.

[ImpalaSlayer]

you should be able to find some shell rotella, made for big trucks and such. its what we usly run in our equipment

[Blackened300a]

you should be able to find some shell rotella, made for big trucks and such. its what we usly run in our equipment

We have a local oil company that supplies us with long drain 15w40 detergent oil for all our trucks. That rotella stuff is great but its expensive.

[Breadfan]

Yes i have seen the rotella and 15w40 in the Flaps

[RF Overlord]

Wally's sells Motorcraft 15W-40 diesel.

I found the Cummins motor in our 250 kW standby generator used Rotella at a greater rate than normal. Mobil Delvac, Chevron Delo 400, or Valvoline Premium Blue are better choices.

[Breadfan]

Cool, so long as 15w40 is a good standin for SAE 20 Im good to go. :)

[Seneca]

Cool, so long as 15w40 is a good standin for SAE 20 Im good to go. :)
Make sure you get a CF oil. Comp. Fire Or SF for Spark Fire.. you want CF. take care mike

[Breadfan]

Thanks. I picked up the Shell rotella 15w40.

[Breadfan]

This is for my dads 77 Ford backhoe. There are questions now from him about 15w40 being too thick. I share the confusion.

Can someone explain how this multi viscosity 40 weight oil is recommended as a stand in for single weight sae 20?

Its not that i disagrew so much as i want to understand the reasons while being able to properly answer this question he asked me beforw i change it tomorrow...

Thanks!

[FordNut]

I would go with the recommended straight 20W

Again...
No questions that way.

[Breadfan]

Thx sounds like i need a trip to tractor supply