Been running 0W-40 Mobil 1 FS European Car Formula for 2 weeks now


Please go back and read my post carefully. If you read my post IN DETAIL, I state that the F150s never had 300ci/4.9L engines which had piston improper-size issues, nor did they have forged internals.

I NEVER said F150s didn't get those engines. I said that they didn't have those PROBLEMS (which could cause piston slap; the topic of disucssion).
 
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i like m1 0w-40 as much as the next guy, but the cold start piston noises from my 505 pontiac are the same as they were with any other oil... 2618 alloy is noisy when cold!
 
Well now that you mention it, that is an interesting topic. I had been running Fram Ultra filters exclusively but this last oil change I went to Wix XP. But, with that being said I would get 85psi oil pressure with the Fram filters within 1-2 seconds so I don't think that was the issue.

The sounds I'm attributing to piston slap is the sound I would get only when going out to start the car first thing in the morning. Not really concerned with it, I knew I would have it going into the build. I just found it interesting I can no longer hear it.
I had much less startup noise moving from a Fram Ultra to a Wix XP. Both should flow gang busters but ... I tossed the just installed Ultra a week later (which was the original screen backed media design) and installed the Wix which was also the older gen "better" build.

An FS lubricant might reduce metal stick/slip phenomena. Let's just say you found a "good combo" and leave it at that - at least for these pages.
 
I'm gonna stop you right there.

The only two things which generally cause "piston slap" are:
- improperly sized pistons to the bore
- forged pistons (which expand from warming up at a slow rate relative to the other components)
The F150 never had 4.9L engines which had either, in the 31 year run (1965 to 1996).

Whatever noise you're hearing, I seriously doubt it's "piston slap".


NOTE: The late 60s / early 70s did have some HD versions of the 300 six which did have forged internals, but those were only installed in very heavy service dump trucks, etc. Never into an F150.
Well another thing causing piston slap is the skirts cracking off and falling into the oil pan... I guess that's a Chrysler/Jeep thing 😂
 
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