03gt04mach1

Okay, I've looked through the forums and many say change over to 5w-30 from the 20 on my wifes '04 Mach1. Alright, it seems to run fine on 30. Then on another board I read NEVER go above 5w-20 because of build clearance tolerance issues, 30 not getting the lubrication to the TOP of the engine. And we all know we need all we can get up there with those double-overhead Cams. I've used Mobil1 ever since we bought the Mach1. I can't tell if 30 is better, or go back to 20. It has 82,000 on it now. I thought the engine has loosened up by now for 30 weight anyway. Am I wrong? I can't see where going from 20 to 30 should make that much difference. But, if it does...Someone in the know, PLEASE answer this plea!

rygi23

5w30 synthetic, period. With no change in engine clearances from previous years Ford recommended 5w20 for smog standards and upcoming CAFE regulations, basically being able to advertise their cars getting 1 more mpg, lol. 5w30 synthetic is still a very thin oil, 5w20 is like freaking water, especially after it's viscosity is broken down. Here's a descent thread copied/pasted onto a M1R thread from a while back. Pay close attention to what swhiteh3 had to say. He was a Ford engineer.

http://corner-carvers.com/forums/showthread.php?t=36607

03gt04mach1

Thank you. I knew I read that article in M1R, but couldn't find it again. Thanks again.

94redGTConv

5w-20 is no joke the exact same as 2 stroke oil.


Posted from MustangForums.com App for Android

03gt04mach1

And, we all know we need that extra 2 strokes. Thanks

4vmach1

Just what rygi23 said, if there isn't any clearance issues then 5w20/5w30 is what you should use.