The motor was designed for 5W20 and in later model years Ford made noises about voiding your warranty if you didn't. That being said I use Mobil 1 5W30 with a Motorcraft filter from ChinaMart (WalMart) and haven't had any problems over two V10 trucks and eight years. The Motorcraft filter (FL-820S) has a silicone anti-drain back valve, which helps also. ChinaMart also sells Mobil 1 in a 5 quart "jug" for about $20 which is cheaper than just about anywhere.

 

wondering about final outcome of tapping noise. my truck just started at 120,000 and I am pretty sure it is a lash adjuster. adjusters can be replaced without head or cam removal, but you need a special tool.

 

I realize this post is likely very old. But I have heard of a plastic peice in the head plastic head cover that can come close and bang around in there. If that is the problem it will not sound like metal. It will not 100 percent change with the rpm. And putting your hand on the head cover you will feel it. The cover is redesigned so a replacement cover would be the solution.

 

the last post in this thread was june 11 2006 'highly doubtfull anyone will read your post

 

I read it. Don't even know how i got here.

Funny too though. Dad's 2000 v10 has run 10w-40 amd then 20w50 forever. 200k and is quieter than my 2010 v10. Maybe the 3v made me noise.. idk. Mines not stupid loud and no concern. But I drove his a couple days ago and it's noticeable. Mine has far more power but mines 3v and manual and 4.10. His is 3.73 and 2v and auto.

I've preached how "oil passages are smaller on newer engines" but he runs 10w40 in vehicles that ask for 0-20 and never lost a motor. Lol

 

maybe you'll also chuckle. i to never ran light oils in my 05, i worked for vw got 15w40 castrol edge eurospec for free, motor never complained or gave any indication it didn't like it, never used a drop either.