No. I know people who have switched to synthetic at 50,000 miles and not had a problem. The earlier the better because it dramatically reduces wear on the engine.

 

As far as amount of oil, your owner's manual will tell you.

On a 4.6, it should be 6qts with a filter. I run Royal Purple 5W20 and a Motorcraft Filter in my 4.6 Mustang.

 

Hmm, I'll have to do some more research... thanks.

 

It depends moreso on the condition of the engine and the seals. If it is in great/good condition, it shouldn't be a problem. In an engine with leaks, synthetic oil (the molecules being perfectly smooth) will run out of the leaks much better than regular oil.

 

Yea, the 98 5.4L is the fastest F150 - that I've been in anyway- it's a runner now.

No nothing I want to give away - I keep doing that and screwing myself for later. I have 3 F150's here and always use the parts . Only thing I have in bulk is EVR's and IAC's, not new - bought them off ebay. I have a new EGR valve - A ford one for your truck that won't fit any of the trucks here. I'll sell it cheap.

 

so would i be crazy to buy a new truck with 5 miles on the engine and drop the oil and fill it with synthetic or should i wait until it's time to change the oil?

i always swore by synthetic oil but i never put it in a brand new engine.

thanks.

 

maybe an IAC would be cool. that werid humming noise happends every now and then still. i got an EGR off a ranger i think they were the same. it works maybe in these next few weekends will head out that way and line um up. you goin to the monster jam?

 

Humming noise is normal, doesn't hurt anything. I might have an IAC. I gave my new one away to faster150 - It was for a 4six , I didn't need it. I have a used one that came off a 3.8 that might work.

No plans for Monster Jam yet.

 

Most recommend waiting until the first scheduled oil change (2,000 miles or more usually), so the engine can break-in with the regular oil. Just go to the first oil change and you'll be set. There is a benefit to the crudeness (compared to synthetic) of regular oil during break in.

Here's from Royal Purple:
Can I put Royal Purple into my brand new car?
Yes. Royal Purple currently offers many viscosity grades of API-licensed motor oils. To allow for proper break-in of the engine, Royal Purple recommends waiting until the manufacturer’s first scheduled oil change or a minimum of 2,000 miles in new gasoline engines. Allow 8,000 to 10,000 miles before using Royal Purple in diesel engines.

 

when i frist cleaned my IAC it seemed to get rid of it for about a month but i was lisening to it after i put a differnt plug in cyl 3 and it made a really loud humming noise out of my CAI its so loud i can even hear it in the cab and if i hold that RPM it will keep humming untill i give it more gas. me and 2 of my buddys are going were gonna tail gate....tail gating was more fun at the silver dome.

 

Oh, that's a different humming noise than I was thinking of. That's PCV , IAC or intake originated. That black box that's stock on your intake that goes to the IAC is a muffler. That silences the IAC.

 

oh. ive never replaced my PCV. also is there 2 of them theres one on the passenger side cover that goes to the TB and one on the driver side cover there is a hose going from the cover to the CAI pipe under the CAI hose.