What brand/viscosity of oil should i use?

its a 1991 madza 4cyl. and it also has 197k miles on it i live in philly (climate) and should i use slick 50 or lucas in my oil change?What brand/viscosity of oil should i use?
Don't waste your money on Slick 50 or Lucas. Just use the factory recommended 10w40 grade, of a namebrand oil.





If you lived in Alaska, you could maybe run 5w30. Especially with your mileage, I'd definitely stick with the heavier 10w40. Synthetics aren't a bad idea, there are some benefits but they're not necessary.What brand/viscosity of oil should i use?
15w 30 or mobil1 light weight dont use heavy weight unless you like engine sludge
Use the viscosity of oil recommended by the manufacturer (I agree that it is probably 5w30 but check just to be safe). As far as brands I would use either Mobil 1 synthetic or Pennzoil Platinum synthetic. I would NOT put any oil additives in. Grab a sample of your oil and send it in to Blackstone Laboratories and get an oil analysis. That will let you know what type of engine wear you have going on and the frequency that you should be changing your oil as well. You might be able to get another 100k to 150k out of your Mazda!
I wouldn't waste my money on Slick 50 or Lucas. If your car is not burning oil, then continue using the oil recommended by the manufacturer. If it's burning oil, then go to a 20/50.





Just about any major manufacturer of oil will work fine in your car. Just change it when you're supposed to. Heavy duty use, turbo, supercharger or racing will require better oils but general driving will be OK with regular oil.





Site showing that Slick 50 isn't the best or good product to use: http://skepdic.com/slick50.html





Another site showing the Lucas causes foaming (not a good thing): http://www.bobistheoilguy.com/images/luc鈥?/a>
Doesn't matter just use normal 5w 30 and you'll be fine.
I wouldn't use 30 weight oil, it has pretty high milage. I would either go with 10 w40 or 20 w 50, I would stay away with any oil additive.
It is a misconception that a heavier weight oil is needed in a older car use a 5W30 fully synthetic oil such as Mobile One, don't use additives the oil does not break down, change the oil and Filter regularly. It will be as fine in philly as it would be in florida.