Sae 30 or 10W30???

[derek4325]

Please don't hate me for ANOTHER oil post but i think this one is legit. So my manual calls for sae 30 (1988 5.7) HOWEVER. I noticed that the oil fill caps had gray paint on them (looks to be the exact same paint the rest of the engine is painted) and underneath the paint it says 10w30 and to read the manual... the manual says multi viscosity oils is not reccomend.. so what do they want from me? Lol

 

[vasy]

SAE30 will do fine. But seems lots just use diesel 15w-40 Shell Rotella T-4 oil.
https://www.walmart.com/ip/Shell-Rotella-T4-15W-40-Heavy-Duty-Diesel-Oil-1-gallon/181236405

 

[Scott Danforth]

Please don't hate me for ANOTHER oil post but i think this one is legit. So my manual calls for sae 30 (1988 5.7) HOWEVER. I noticed that the oil fill caps had gray paint on them (looks to be the exact same paint the rest of the engine is painted) and underneath the paint it says 10w30 and to read the manual... the manual says multi viscosity oils is not reccomend.. so what do they want from me? Lol

in a vehicle where the oil filler cap came from, multi-vis is fine.

however in a loaded application such as a boat you want heavier oils. single vis is better, however in your motor, I would run Rotella T4 15W-40 diesel (at $11 a gallon) and go boating. (your motor is a 1988 flat-tappet motor - you need the zinc), and Rotella T4 is one of the few oils left that is still high in zinc

 

[aimlow]

Oil has changed in the last 30 years. Do what Scott says. Forget the cap.

 

[derek4325]

Okay thank you for the responses.... so how about this.. i was at walmart the other day and i see they have shell sae 30 diesel engine oil. Im thinking about getting it as long as its in the same ppm range as the 15w 40. I would like to adhear to the manual and avoid the multi vis if at all possible. Advisable? Thank you

 

[Scott Danforth]

your over-thinking it. grab the rotella and go boating

 

[derek4325]

your over-thinking it. grab the rotella and go boating

Im going to stick with the rotella but i have a choice between 30 and 15w 40

 

[Bondo]

Im going to stick with the rotella but i have a choice between 30 and 15w 40

Ayuh,..... It don't matter,..... Whichever trips yer trigger is just fine,.....

 

[aimlow]

Okay thank you for the responses.... so how about this.. i was at walmart the other day and i see they have shell sae 30 diesel engine oil. Im thinking about getting it as long as its in the same ppm range as the 15w 40. I would like to adhear to the manual and avoid the multi vis if at all possible. Advisable? Thank you

The manual is 30 years old. Jeez.

 

[derek4325]

Thanks everyone, i was not aware of the difference between flat tappet motors and just regular roller cams. Thank you for helping me understand the importance of zinc. And aimlow.... youre right oil has changed in the last 30 years but so have engines. Multi vis oil has been around in 1988 just as much as its around today. And when a manual specifically says DONT use it.. then dont. Doesnt matter how old the manual is.. just my .02

 

[vasy]

Thanks everyone, i was not aware of the difference between flat tappet motors and just regular roller cams. Thank you for helping me understand the importance of zinc. And aimlow.... youre right oil has changed in the last 30 years but so have engines. Multi vis oil has been around in 1988 just as much as its around today. And when a manual specifically says DONT use it.. then dont. Doesnt matter how old the manual is.. just my .02

Your $0.02 don't worth much. Oils have changed but YOUR engine has NOT. You still have a 1988 engine even though it is a 2018. Your engine is 1988, 10 years from now it will still be 1988 engine but the oil you put in it might have changed chemistry yet again.
So yes, it DOES matter how old the manual is, just depends regarding what. And no, it is not wrong to run your engine on SAE30, but from others vast experience it is also fine to run the 15W40. And no, not every 15W40 is the same, that is why there is only one brand recommended, not just any.

 

[Lou C]

As far as the 30 wt vs the 15w/40, the main difference would be is if you use the boat in cold weather, the 15w/40 would allow better cranking for cold starts vs the single weight 30.

 

[derek4325]

Your $0.02 don't worth much. Oils have changed but YOUR engine has NOT. You still have a 1988 engine even though it is a 2018. Your engine is 1988, 10 years from now it will still be 1988 engine but the oil you put in it might have changed chemistry yet again.
So yes, it DOES matter how old the manual is, just depends regarding what. And no, it is not wrong to run your engine on SAE30, but from others vast experience it is also fine to run the 15W40. And no, not every 15W40 is the same, that is why there is only one brand recommended, not just any.

I don't think you understand what you are replying to. What im saying is the chemistry of oil is changing along with the engines being made TODAY. Which is why it is critical to keep your oil as period correct as you can by following the manual. Common sense. OBVIOUSLY the engine will be an 88 ten years from now. In this case i learned from the people here who are actually helping me with a very simple question about the importance of zinc hence using diesel oil. End of story. I understand people use multi vis oil and have no problems. I choose not to. No need to be bashful. Good day

 

[aimlow]

Horsecrap. Engines today are virtually the same as those engines. Iron, steel, aluminum, lead, brass, virtually identical clearances. Ever had an engine apart?

 

[derek4325]

Horsecrap. Engines today are virtually the same as those engines. Iron, steel, aluminum, lead, brass, virtually identical clearances. Ever had an engine apart?

Re read that again very very slowly. Then take a history lesson and read it again. Going to disable comments on this thread. Question has been asked and answered. Thank you to those who contributed with meaningful information.