: Oil Weight Question



JohnnyO
09-07-04, 03:04 PM
My mother's '99 N* calls for 10w-30 oil. My dad's '04 N* calls for 5w-30. Are there any internal differences in the engines between those years, or is the 5w recommendation just for CAFE mpg purposes? The reason I ask is that my dad's car goes to Florida in the winter and won't really get run much in cold weather. (Dad's FL house is still standing btw.) I use Mobil 1 and AC filters in both cars. Thanks.

caddydaddy
09-07-04, 03:17 PM
One of the major differences was the switch to full roller lifters in 2000.

Anthony Cipriano
09-07-04, 10:31 PM
There were lots of changes in the Northstar engine for 2000 and later. The roller valve train was one of them. Basically, most every part in the engine changed. 5W30 is the recommended oil for all seasons in the 2000 and later engine. I would recommend using that. The 1999 and earlier engines need the 10W30 viscosity because of the flat follower cams. The flat tappets need the extra viscosity to maintain a hydrodynamic bearing film at low speeds between the cam lobe and the lifter interface. I would recommend 10W30 most all the time except in the very coldest climates during the winter if cranking speeds are an issue on cold starts.

JohnnyO
09-08-04, 06:22 AM
Thanks. Mostly I was wondering if I could put 10w-30 in the '04 since it doesn't see cold weather, then I'd only have to buy one oil. Three 5 quart jugs at Wal-Mart would be perfect for changing the oil in both. I'll stick with the 5w in the '04.

Anthony Cipriano
09-08-04, 11:08 AM
Thanks. Mostly I was wondering if I could put 10w-30 in the '04 since it doesn't see cold weather, then I'd only have to buy one oil. Three 5 quart jugs at Wal-Mart would be perfect for changing the oil in both. I'll stick with the 5w in the '04.

Yes, you can use the 10W30 in the 2004 with no problems. Just the fuel economy will be penalized slightly. The 2004 motor will be fine with either. I was thinking of the other substitution obviously.

Ranger
09-08-04, 12:21 PM
How much of a decrease in milage would you realisticly expect to see by using 10w30 vs 5w30? OR is it theoretical and so small that it would hardly be noticable?

lowscola
09-08-04, 04:35 PM
Remember the Jugs are only 4.5 quarts.

Anthony Cipriano
09-08-04, 08:13 PM
How much of a decrease in milage would you realisticly expect to see by using 10w30 vs 5w30? OR is it theoretical and so small that it would hardly be noticable?

Probably a few tenths of a MPG in the city and maybe .3-.4 on the highway.

JohnnyO
09-09-04, 11:25 PM
Remember the Jugs are only 4.5 quarts.

:coolgleam The jug says 5. Are they ripping me off?

lowscola
09-10-04, 05:01 PM
:coolgleam The jug says 5. Are they ripping me off?

I know most of the oil jugs are 1 gallon, and to correct my previous post:

1 gallon = 4 quarts = 3.785 litres so it's really just 4 quarts of oil in the 1 gallon jugs. I always buy two for the Caddy makes oil changes alot easier. Are you sure it says 5 quarts? If so their doing a UK gallon to US quart conversion or something...

Ranger
09-11-04, 12:59 AM
The ones I buy are 5 qts.

jgr7
09-12-04, 01:43 AM
The Castrol jugs I buy at Walmart are 5qt , 4.73L.
Jeff

lowscola
09-16-04, 02:00 PM
Thanks, I'll have to look for those Castrol Jugs. Been using the Penzoil ones...