DGreen,

In my opinion, I would never add any insta-sludge additives like STP to my engine ever. The best option is to run Mobil 1 synthetic oil and change every 3,000 miles along with using the Motorcraft filter. My son was having an oil leak problem with his oil pan gasket and so decided to add STP to stop the leaking. Not only did it not work, when I had the pan gasket replaced, the mechanic said the engine had a lot of sludge. He asked me speciifically if anyone had added any STP oil treatment to the engine. Need I say more!

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1998 RED F250-LD EC 4X4 Lariat, 5.4L, 3.73LS, 4WL ABS,
LOAD LVL SUS, TOWING PKG, SUPER COOLING PKG, 6 CD
CHANGER. GREY LEATHER INTERIOR.

MODS: PACESETTER TFX CAT BACK EXHAUST
AIRAID INTAKE SYSTEM
SUPERCHIP FLIP CHIP
MAG-HYTEC DIFFERENTIAL COVER
NAPA CERAMIC BRAKE PADS
BFG ALL/TA KO LT26575R16
FORD MOLDED MUD GUARDS
DURALINER W/ BULL RING TIE DOWNS
MAX SUPER WHITE HEADLIGHT & FOG BULBS
DASHMAT DASH COVER

FUTURE MODS: JBA HEADERS
STULL BILLET GRILLS
MAGNACHARGER BLOWER

 

I would certainly not use it in any new engine..and instead would change the oil and filter by the book. The oil additives do not serve much of a purpose..however..there might be some minor benefits with high mileage engines.

I have also heard about this kind of stuff causing sludge. When added to regular oil, it tends to raise the viscosity and it can in turn cause engine problems..like sludge.

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2000 F-150 XLT, 4x2, 5.4L Supercab, Superchip, Styleside, Black with silver two-tone, 3.55 rear, class III towing package with heavy duty cooling package, 4 wheel disk ABS, overhead console, sliding rear window, keyless entry, dark graphite interior, in dash CD, factory leather wrapped steering wheel, Pendaliner bedliner, K&N air filter, rubberized undercoating, cabin filtration system, Bugflector II, 5W-30 Mobil 1, engine build 10/4/99

 

Great guys, will stay away from the "sludge" then. Now, change the oil every 3,000 or 5,000? The book actually says every 5000....but I've always done the 3000 change on trucks

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2000 F150 XLT 4.6L V8 Auto, SuperCab, Torreador Red, Magnaflow Cat-Back Exhaust, K&N Drop-in, 265/75/R16 Futura Mud Terrains, Ford Bedliner, Tinted Windows
www.geocities.com/y2kf150

 

3000 miles. Its the cheapest insurence policy you'll ever own!!

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"99" F-150 4x2,ext, med red / silver, 4.2L, auto, 3.55's, 265x16's premium snd w/cd, 4 wheel antilocks, leer "too heavy" matching cap, Mobil 1.

 

Hey guys, I used to add STP to my oil in my previous truck. I was going to add it to my F-150, but I noticed the manual for the truck discourages it. Anyone have ny opinions?

Thanks

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2000 F150 XLT 4.6L V8 Auto, SuperCab, Torreador Red, Magnaflow Cat-Back Exhaust, K&N Drop-in, 265/75/R16 Futura Mud Terrains, Ford Bedliner, Tinted Windows
www.geocities.com/y2kf150