I don't know my V-8 stuff. 1998 4.6 liter. Do these Trucks need the high Zinc oil?

I would guess that's too new to worry about it.

I'm a Ford guy and have a 4.6. These engines are really stout and well-designed. Since they're SOHC with hydraulic cam followers (lash adjusters), you really just need to worry about good clean oil, of the right weight, rather than oil with a ton of additives. I used Mobil 1 for a long time, but since this car is now well over 200K miles, I believe the OEM Motorcraft Synthetic blend is a great alternative for an older engine in it's second half of life. Even with over 200K I use the factory-recommended 5W-20. Ford switched to 5W-20 specifically on these motors for a reason - These engines have a ton of very tight tolerances, especially in and around the valvetrain, so I stick with that they recommend.

Thanks George. I didnt know they switched. What year is your truck?

Its a 1996 Mustang actually. Same basic engine, but I think the trucks got a bigger main bearing saddle and different flowing heads (more torque). '96 was the first year the "modular motor", i.e. the 4.6, was put in the Mustang. They had already been using it in the Crown Vics and Lincolns for awhile, so they got most of the bugs worked out.

Again, 5W20 is what is supposed to be in there, and even though I have to add a quart about every 2 months, I'd rather do that than starve the bearings, lash adjusters, etc because I used something too thick. Motorcraft is a great oil, IMHO.

Have you had to change out the intake manifold yet? This is a very common problem on the 4.6 and 5.4s as the plastic cracks or is degraded around the coolant crossover tube at the front of the engine. Keep an eye out for it. Fairly easy fix, just takes about an afternoon worth of work and $200 for a new manifold. Other than that, basically bulletproof (even with tons of boost I'm told).

I just got the truck. Basically it's my sons first vehicle. I haven't seen the crossover pipe yet. What does the replacement look like? is it different than the original?

Great first vehicle! Again, the drivetrain should last forever and most parts on those trucks are fairly cheap and easy to fix. Not super on gas, but not as bad as a big honking suburban or larger truck either.

The manifold crank problem is discussed here: http://www.agcoauto.com/content/news/p2_articleid/185

And the area that is prone to crack on the original all-plastic manifolds is at the front:

Eventually the heating and cooling of the antifreeze weakens the plastic in this area and a crack develops. Not so much a question of "if" but "when." The solution is a replacement intake manifold, all of which have an aluminum crossover (which was Ford's recall solution, though the recall date has long since passed).

If the truck already has the aluminum crossover tube, that means the intake has already been replaced. Mine was like that when I bought it, but I still ended up putting another intake on it this past year. The plastic had gotten brittle under the aluminum crossover and cracked. So, basically every ten years or so they need to be replaced. Again, not a big deal and a fairly easy fix if you can devote a days worth of work.

Thanks for all this info George. I cannot remember what I have got, but with 163k miles it sounds like it would be a miracle if the plastic was still there. I'll check it out later when I'm home.

The 5.4s have a Aluminum Crossover Tube, but the Plastic WILL Crack somewhere!

I echo the Motorcraft synth blend...for later Ford products..