Hey people,

I'm do for another oil change this week and i was wondering what type of oil do you guys recommend. I have an 03 6mt coupe with 53,888 miles on it. My (60k service is just around the corner!)

 

Other than fuel economy [for EPA Test] oil viscosity [and brand] should be determined by measuring the extreme hot idle [say after an hour at 80 mph AC on expressway] oil pressure.

With the engine as hot as it can get [normally] this is worst case conditions when you want the correct viscosity for the bearing clearances.

Something that will yield a minimum of 13-15 psi @650 rpm..........don't let motor cool to much.

As the oil gets dirty and evaporates and get thicher the pressure will increase so use brand new oil for the test.

Important to graph pressure vs rpm vs hours of use to determine rpm where oil filter opens bypass.........cruising at 70 vs 80 mph new oil vs used oil.

Synthetics have a lower NOACK [amount that evaporates per hour at extreme heat] and a more consistent viscosity with hours/age.

After 275,000 miles using 10w30 conventional and synthetics I'm now using 10w40 for the last 32,000 miles..............a 90Q V8 was very very tight and suffered from little wear over 16 years. I measured my hot oil pressure every year from 7 on to decide on oil.

The finest thing you can do for engine is to change oil every 90 days [even if you don't drive 1000 miles] and check it and add if necessary every week!