Any 20 or 30 wt oil. The car's respond much better to the thinner weight oils. You'll notice a difference in how easily they rev and respond to throttle with the lighter weight oils. Oil flow is extremely important in the L3 engine, the car runs over 90 psi of oil pressure. Even at 3000 rpm, it can be pushing as high as 80 psi depending on load. Obviously a thick oil at startup is a big no-no for these engines.
Here's a list of Mazda 6i used oil analysis...remember the engine in the 3s is identical for all needs and purposes.
I'd stick to motorcraft 5w-20, Mobil 1 5w-20 (0w-20 if you can find it), redline 5w-20, or 0w30 GC.
Alot of these used oil analysis involve people who race and modify their car, so there really isn't any worry about a 20 wt not performing, when the wear metals are well in the green...even though their tracking the car's in high heat and humidity environments.
http://www.mazda6tech.com/index.php?option=content&task=view&id=26
The biggest thing to worry about the 3s/6i isn't the oil...its the oil filters. The plastic cap on the cartridge housing is EXTREMELY vulnerable to damage. Just trying to twist it off once with metal pliers can destroy the cap, cause hairline cracks to form, and result in oil starvation (running oil psi is over 90!...its like a garden hose if the cap blows), and engine destruction.
Avoid taking your car to any quickie lube shops (its been banned from some already) unless they specifically know and understand they have to use the mazda tools to remove the cap. Otherwise just take it to the dealer, convert it to a spin-on filter, or do it yourself.
[ February 10, 2005, 04:13 PM: Message edited by: crossbow ]
