So I finally swapped over from 5w30, and I have to say is that I'm impressed. I've been running Mobil 1 with a Mobil 1 Filter - intervals of 5K- and I have always had a "Clacking" at every start up for about 5 seconds. (Ever since I ran Castrol Syntec back 2 years ago). But now - nothing. Dead quiet minus the injectors firing. Threw in Mobil 5w20, with a Motorcraft filter. I recommend the change to anyone! We'll see if 5w20 burns faster than 5w30. I hope not, I burn through one quart every 5,000 with 5w30

 

1 qt per 5000 miles is pretty normal, and the "Clacking" you got is probably from that mobil filter, im not sure if they are up to par with wix, purolator, and motorcraft on these engines.

how long were you running 5w30? im not sure if switching weights after to long is a good thing

 

I switched my van to 5w-20 when it had around 175k on it. Didn't hurt it. Its got 225k on it now. I did it because the walmarts around here rarely have 5w-30..

 

I've heard Mobil Filters were up to par for a long term filter...but maybe not.

 

really?? wow most of the vehicles i see recommend 5-30

 

I should have also said Motorcraft 5W-30. They are always out of it when I try to get it..

 

OHH!! makes sense

 

I feel that switching to 5w20 wouldn't be harmful come to think of it, because that is now what ford is recommending for our year trucks.

 

well i think after you run a wrong weight for so long the motor gets used to it or something like that, ive read it before on a thread something about the bearings and timing chains blah blah complicated *** ford engine blah!

haha, anyways yea 520 should be alot better!

 

I've heard that for synthetic. Once you go synthetic you aren't supposed to go back because of the seals and what not.

 

hell, who knows. run 5w20 with no worries! thats what id do