'98 5.4 Engine "Rattle"

[garyfort]

hey all i have a 97 expy and found out today that a lot of tritans break exhaust manafold blots on the passangers head and when u start up in the morning it will sound just like a rod or pistin slap and then it will subside..................im haveng mine fixed in two week thats the soonest the shop can get me in will cost around 400.00 for new manafold and bolts and studs

 

[green03]

You could very well have an exhaust leak that gets quiet when the materials expand (when hot) and re-seal the leak. You could also have the famous ford piston slap.
As far as the oil questions, Mobil 1 5w30 is good oil especially if you rev the engine alot 5w20 doesn't provide enough protection at higher rpms. If you use a full synthetic 5w30 you will get better mileage than the factory blend 5w20. They went to 5w20 to try and squeeze better mileage out of the lower revving engines.

 

[Silver Ex]

My problem was someone used a solvent-based motor flush, didn't drop the pan afterwords and the debris it shook loose scored the crank journals and main bearings. Had a crank kit installed (under warranty), new exhaust manifold gaskets and one new manifold (it had cracked), and new head gaskets because the heads had to be milled and the valves ground (the mechanic installing the crank kit didn't compress all of the valve lash adjusters before re-assembling the engine and it bent valves on initial start after the engine was re-installed in the truck). Even after an almost complete rebuild, the engine is still a little noisy. Its noisy because the 5.4s are noisy...my buddy has a 2001 F150 Super Crew and his 5.4 rattles, too. You get them over 75K and most of them make noise. I just turn up the radio and hit the trail...it runs strong, burns no oil and goes all day long without any problems other than being VERY thirsty!

Since the rebuild I'm using Valvoline 5W30 synthetic blend.