motor oil and gas - recommended?

[Soma576@xxxx]

Hey all,

i was going though my shop manual today and noticed that it recommends 91 
octane gasoline for the car. i've been using 89 octane. yes i know what the 
rating means, but is there a good reason i should be using 91 instead of 89?

second, it recommends some pretty heavy motor oil. it says that 15w40 is a 
recommended weight! i've done over a thousand oil changes at the part time 
job i work at, and i've never put oil like that in a car - the only engines 
that use that (Rotella, usually), are big diesel pickups!! it's 'the diesel 
oil'. what do most people use? it says regular 10w30 is ok but only in cold 
temperatures.

sorry if these questions are really stupid, but i've been chatting with other 
DML'ers and they have just kinda shrugged too!

Andy

Soma576@xxxx
1982 DeLorean DMC-12 VIN#11596
Fargo, ND 58102


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