I have 3.7 V6 and I changed my oil at 7000 miles to Full Synthetic M1 5w20 with a Mobil 1 filter as well. Now when I am hitting around 2000 RPMs and going a moderate speed, I can hear the valves rattling a bit. It did not do this with the original conventional crap oil. What is going on here? I am taking it to the dealer this weekend, but maybe it is something simple that I can do so I don't have to. I also added some Lucas Full Synthetic additive which has quieted it down somewhat, but the rattle is still there! Maybe I should go to 5w30, or back to synthetic blend since it is thicker?? Any ideas would be appreciated!

Thanks,
Brooks

 

man, did exactly as you did at 7000 with mobil 1 synthetic and had no problems, keep us informed