Northstar Engines and System Technical Discussion Discussion, More OIL STUFF in Cadillac Engine Discussion; I read that the most efficient oil for the Northstar and other newer engines is GF3 rated oils.
Mobil One ...
I have always heard that if you can use 5w30, you can use 10w30. The EPA "edges" them to use 5w30 because since it is thinner, it gives better gas mileage. I dont think that using a thinner oil would make it burn more oil, but i can see where you are coming from. It would make sense that a little tiny bit of oil could get past the rings. I really dont think there is any way around the northstar using oil. Just think of it this way, you can use a little more oil or you can get your engine rebuilt every 100k.
As far as the GF3 or GF2, im not sure what that is supposed to mean.
Lots of years ago I had a '54 Ford Victoria.
Pretty car but it had lots of miles on it and burned as much oil as gas. Eventually I started putting straight 40 weight oil in it and that cut the oil consumption in half.
So oil weight does make a difference but the difference between 5 W and 10 W is not much.
I don't think it makes much difference. I had always heard that the smaller the spead in viscosity, the more thermaly stable the oil. Living in southern California means that I don't worry too much about cold weather operation, so I use 10-30. My 94 went about 230,000 miles without any major engine problems, and the commpression was well within spec when I did the last tune-up at something less than 200,000 miles. It passed California emissions at the time of sale, so the engine had to be in fairly reasonable shape. And that was using whatever name brand oil was on sale at the time, no synthetics, and changing the oil generaly at 50 - 20% oil life remaining. And for the entire time that I had it, it used about 1 quart every 1500 miles. It had slight leakage around the middle, and the bottom pan but no drips. A weep might be a better description. So far at 108,000 miles our 97 is about the same, it might use a slight amout more oil. It developed a drip at about 50,000 miles and it was repaired under warranty.
peatea, I read your post about you having a 54 ford. My first car was a 54 ford. It used-leaked oil too. I used to put GEAR LUBE in it to slow down the oil useage. Now I have an ELDORADO. Good to know I'm not the only one with good taste..LOL BTW I got the Biaritz(sp) type vinyl i/4 roof package on the Eldo. Rock On!
mobil1 is the finest OTC oil out there... i wouldnt worry about GF2 GF3... mobil1 meets almost every mfg. spec out there...
the 0w-40 meets mercedes 229.5 spec, one of six oils in the world to do so (for 35k drain intervals.. more likely, 15-20k)
anyways, all the "synthetic" oils out there (valvoline, castrol, pennzoil, quaker state ETC. ETC.) are not true synthetics. they are group III hydrocracked oils, still petroleum basestocks. mobil 1 is the only one to use group IV stock (PAO/Ester based)