I have a 99 Expy with a 5.4, which I changed over to 10-40 AMSOIL synthetic. It's about time for a filter change, and I was thinking of going to the 5-20 or 5-30, whichever the book recommended. We live in FL, so it's almost always warm-hot, which is why I opted for the 10-40. Any experience or thoughts on the 5-20 or 5-30?

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I use 5-30 in my truck as well as mommas car. 10k between oil changes. 44k on the truck, 64k on the car. no problem. I use Amsoil products thru out, engine, trans rear et...

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99 F-150 XL 4x4. Reg Cab Flareside 4.6 5spd, 3.55LS. gibson 3" cat-back, K&N Gen ll.Westin step bars.Ventshade window deflectors and bug deflector. rhino liner and a cool white shifter ball.

 

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You know, you might be right. In fact, I'll have to go back and look at the bottle and see which one I put in. I have AMSOIL in all my other vehicles also, so I might have confused my self.. I know the motorcycle dealer always shies away from me putting it in because of the clutch. Anyway, you are right, the manual says clearly 5-30, and that's what I will use. Sometimes pays to go back and look at that book sometimes. Thanks

 

From everything I've read and heard from the experts, its NOT a good idea to use an incorrect viscosity in todays engines.

That said, I would go with 5W-30 like your manual says or 0W-30 which has slightly better properties and reaches critical parts faster.

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Rand

98 Ford Expedition 4X4 XLT
5.4, 3.73s, 17" wheels,
Homemade 3" "COLD" Air-Box
mod, SuperChip, Amsoil
everywhere but tranny, Perma-
Cool combo 6 pass trans/oil
cooler (FQR 5.4 @ 50K)

NEVER BUY EXXON/MOBIL! ITS A CRAPPY
PRODUCT AND THEY'RE AS SLEAZY AS CLINTON!